\input texinfo   @c -*-texinfo-*-
@setfilename ne.info
@settitle @code{ne}'s manual
@dircategory Text creation and manipulation
@direntry
* ne: (ne).                     The nice editor
@end direntry
@defindex cm
@include version.texinfo

@ignore

This file, besides being a normal Texinfo file, allows generation of
on-line help and other crucial parts of the C source code for ne. The
program info2src.pl (a *very* dirty hack) does this. See the Makefile
to see how this is done.

Conventions:
	@file for files, directories, etc. (but extensions, etc. use @samp);
	@code for command line stuff, internal commands, environment variables;
	@samp for menu/menu item names, and anything left that's literal.

@end ignore

@ifinfo
This file documents ne @value{VERSION}, a free text editor for @sc{un*x}.

Copyright (C) 1993-1998 Sebastiano Vigna.
Copyright (C) 1999-@value{RELEASE_YEAR} Todd M. Lewis and Sebastiano Vigna.

Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

@ignore
Permission is granted to process this file through TeX and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).

@end ignore
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the entire
resulting derived work is distributed under the terms of a permission
notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation approved
by the Free Software Foundation.
@end ifinfo

@setchapternewpage odd
@finalout

@titlepage
@title ne
@subtitle A nice editor
@subtitle Version @value{VERSION}
@author by Sebastiano Vigna and Todd M. Lewis

@page
@vskip 0pt plus 1filll
Copyright @copyright{} 1993-1998 Sebastiano Vigna@*
Copyright @copyright{} 1999-@value{RELEASE_YEAR} Todd M. Lewis and Sebastiano Vigna

Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the entire
resulting derived work is distributed under the terms of a permission
notice identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation approved
by the Free Software Foundation.

@end titlepage

@ifnottex


@node Top
@top

This file describes @code{ne} version @value{VERSION}, a free text editor that runs
(we hope) on almost any @sc{un*x} machine. @code{ne} is easy to use for
the beginner, but powerful and fully configurable for the wizard, and
most sparing in its resource use.

@noindent Copyright (C) 1993-1998 Sebastiano Vigna@*
@noindent Copyright (C) 1999-@value{RELEASE_YEAR} Todd M. Lewis and Sebastiano Vigna

@end ifnottex

@menu
* Introduction::
* Basics::
* Reference::
* Commands::
* Configuration::
* Hints and Tricks::
* Motivations and Design::
* The Encoding Mess::
* History::
* Portability Problems::
* Acknowledgments::
* Concept Index::
* Command Index::
@end menu


@node Introduction
@chapter Introduction
@cindex LITHP
@cindex Features
@cindex vi
@cindex POSIX
@cindex terminfo
@cindex termcap


@code{ne} is a full screen text editor for @sc{un*x} (or, more
precisely, for @sc{posix}: @pxref{Motivations and Design}). I came to
the decision to write such an editor after getting completely sick of
@code{vi}, both from a feature and user interface point of view. I
needed an editor that I could use through a @code{telnet} connection or
a phone line and that wouldn't fire off a full-blown
@sc{lithp}@footnote{This otherwise unremarkable language is
distinguished by the absence of an @samp{s} in its character set; users
must substitute @samp{th}.  @sc{lithp} is said to be useful in
protheththing lithtth.} operating system just to do some editing.

A concise overview of the main features follows:

@itemize @bullet{}

@item
three user interfaces: control keystrokes, command line, and menus;
keystrokes and menus are completely configurable;

@item
syntax highlighting;

@item
full support for UTF-8 files, including multiple-column characters;

@item
64-bit file/line length;

@item
simple scripting language where scripts can be generated @i{via} an
idiotproof record/play method;

@item
unlimited undo/redo capability (can be disabled with a command);

@item
automatic preferences system based on the extension of the file name being
edited or regex content matching;

@item
automatic completion of prefixes using words in your documents as dictionary;

@item
a file requester with completion features for easy file retrieval;

@item
extended regular expression search and replace @`a la @code{emacs} and
@code{vi};

@item
a very compact memory model---you can
easily load and modify very large files, even if they do not fit your core memory;

@item
editing of binary files.

@end itemize


@node Basics
@chapter Basics

@noindent @i{Simple things should be simple. Complex things should be
possible.} (Alan Kay)

@code{ne}'s user interface is essentially a compromise between the limits of
character driven terminals and the power of GUIs. While @emph{real} editing is
done without ever touching a mouse, it is also true that editing should be
doable without ever touching a manual. These two conflicting goals can be
accommodated easily in a single program if we can offer a series of interfaces
that allow for differentiated use.

In other words, it is unlikely that an @code{ne} wizard will ever have to
activate a menu, but to become an expert user you just have to use
the menus enough to learn by heart the most important keystrokes. A good
manual is always invaluable when one comes to configuration and esoteric
features, but few users will ever need to change @code{ne}'s menus or
key bindings.

Another important thing is that powerful features should always be
accessible, at least in part, to every user. The average user should be
able to record his actions, replay them, and save them in a humanly
readable format for further use and editing.

In the following sections we shall take a quick tour of @code{ne}'s features.

@menu
* Terminology::
* Starting::
* Loading and Saving::
* Editing::
* Basic Preferences::
* Basic Macros::
* More Advanced Features::
@end menu


@node Terminology
@section Terminology
@cindex File
@cindex Document
@cindex Buffer

In this section we explain and contrast some of the terms
@code{ne} uses. Understanding these distinctions will go a long way
towards making the rest of this manual make sense.

A @dfn{file} is a group of bytes stored on disk. This may seem rather
obvious, but the important distinction here is that @code{ne} does not
edit files; it edits @dfn{documents}.

A @dfn{document} is what @code{ne} calls one of the ``text thingies''
that you can edit. It is a sequence of lines of text in the computer's
memory---not on disk.@footnote{Actually, it can be in a region of the disk
used to simulate a larger memory. @code{ne} will switch to such a simulation whenever
the computer's memory is not sufficient for editing a file. This means, in particular,
that out-of-memory errors can be caused by insufficient disk space, too.}
Documents can be created, edited, saved in
files, loaded from files, discarded, @i{et cetera}. When a
document is loaded from or saved to a file, it remains
associated with that file by name until the document is
either closed or saved to a different file. Interactions between
documents and files are handled by the commands under the
@samp{File} menu. The @samp{Documents} menu commands only deal with
documents. @xref{Menus}.

Internally, @code{ne} holds its documents in @dfn{buffers}.  A
@dfn{buffer} is a chunk of memory in which @code{ne} holds something.
For example, each document is held in its own buffer, as are any loaded
or recorded macros, undo records, a copy of your last deleted line of
text, a copy of all your previous responses to long input, and several
other things.


@node Starting
@section Starting
@cindex Keyboard usage
@cindex Menu usage
@cindex Shortcuts
@cindex Status bar
@cindex Menu bar
@cindex Control key
@cindex Meta key
@cindex Command line

To start @code{ne}, just type @samp{ne} and press @key{Return}. If you
want to edit some specific file(s), you can put their name(s) on the command
line just after the command name, as for any @sc{un*x} command. The
screen of your terminal will be cleared (or filled with text loaded
from the first file you specified). You can also pipe the result of a
command directly into @code{ne}: it will be loaded and opened as the first
document. See @ref{Arguments} for other command line options.

Writing text is pretty straightforward: if your terminal is properly
configured, every key will (should) do what you expect. Alphabetic
characters insert text, cursor keys move the cursor, and so on. You can
use the @key{Delete} and @key{Backspace} key to perform corrections. If
your keyboard has an @key{Insert} key, you can use it to @dfn{toggle}
(switch from on to off, or vice versa) insert mode. In general,
@code{ne} tries to squeeze everything it can from your
keyboard. Function keys and special movement keys should work
flawlessly if your terminal is properly configured. If not, complain to
your system administrator. If that doesn't help, see @ref{Key Bindings}.

At the bottom of the screen, you will see a line containing some numbers and
letters. This is called the @dfn{status bar} because it reports to you part of
the internal state of the editor. At startup, the status bar has the following form:

@example
 L:       1 C:       1  12% ia----pvu-t------@@A* <unnamed>
@end example

@noindent (the numbers could be different, and a file name could be shown as
last item instead of @samp{<unnamed>}). You probably already guessed
that the numbers after @samp{L:} and @samp{C:} are your cursor's line and column
numbers, respectively, whereas the percentage indicates approximately
your position in the file. The small letters represent user flags that
you can turn on and off. In particular, @samp{i} tells you that insert
mode is on, while @samp{p} tells that the automatic preferences system
is activated. The @samp{*} means this document has not been saved. For a
thorough explanation of the meaning of the flags on the status bar, see
@ref{The Status Bar}.

Once you are accustomed to cursor movement and line editing, it is time to
press @key{f1} (the first function key), or in case your keyboard does not
have such a key, @key{Escape}. Immediately, the @dfn{menu bar} will appear,
and the first menu will be drawn. (If you find yourself waiting for the menu
to appear, you can press @key{Escape} twice in a row.) You can now move
around menus and menu items by pressing the cursor keys. Moreover, a lower
case alphabetic key will move to the next item in the current menu whose name starts with that
letter, and an upper case alphabetic key will move to the next menu whose
name starts with that letter.

Moving around the menus should give you an idea of the capabilities of
@code{ne}. If you want to save your work, you should use the @samp{Save As...}
item from the @samp{File} menu. Menus are fully discussed in @ref{Menus}.
When you want to exit from the menu system, press @key{f1} (or @key{Escape})
again. If instead you prefer to choose a command and execute it, move
to the respective menu item and press @key{Return}.

At the end of several menu items you will find strange symbols like
@kbd{^A} or @key{f1}. They represent @dfn{shortcuts} for the respective
menu items. In other words, instead of activating, selecting and
executing a menu item, which can take seconds, you can simply press a
couple of keys. The symbol @samp{^} in front of a character denotes the
shortcut produced by the @key{Control} key plus that character (we
assume here that you are perfectly aware of the usage of the
@key{Control} key: it is just as if you had to type a capital letter
with @key{Shift}). The descriptions of the form @key{f}@var{n} represent
instead function keys. Finally, the symbol @samp{[} in front of a
character denotes the shortcut produced by @key{Control} plus @key{Meta}
(a.k.a. @key{Alt}) plus that character, @emph{or} @key{Meta} plus that
character, depending on your terminal emulator---you must check for
yourself. Moreover, these last bindings may not work with some
terminals, in which case you can replace them with a sequence: just
press the @key{Escape} key followed by the letter. A few menu items are
bound to two control sequences (just in case one does not work, or it is
impractical).

Note that under certain conditions (for instance, while using
@code{ne} through a @code{telnet} connection) some of the shortcuts
might not work because they are trapped by the operating system for
other purposes (@pxref{Hints and Tricks}).

Finally, we have the third and last interface to @code{ne}'s features: the
@dfn{command line}. If you press @kbd{@key{Control}-K}, or @key{Escape} followed by
@samp{:} (a la @code{vi}), you will be requested to enter a command
to execute. Just press @key{Return} for the time being (or, if you are
really interested in this topic, @pxref{The Command Line}).

In the sections that follow, when explaining how to use a command we
shall usually describe the corresponding menu item. The related shortcut
and command can be found on the menu item itself, and in @ref{Menus}.


@node Loading and Saving
@section Loading and Saving
@cindex Loading a file
@cindex Quitting
@cindex Exiting
@cindex Closing a document
@cindex Opening a file
@cindex Saving a file
@cindex Writing a file
@cindex File requester

The first thing to learn about an editor is how to exit. @code{ne} has a
@code{CloseDoc} command that can be activated by pressing @kbd{@key{Control}-Q},
by choosing the @samp{Close} item of the @samp{Document} menu, or by activating
the command line with @kbd{@key{Control}-K}, writing @samp{cd} and pressing
@key{Return}. Its effect is to close the current document without saving any
modifications.  (You will be requested to confirm your choice in case the
current document has been modified since the last save.)

There is also a @code{Quit} command, which closes all the documents
without saving any modifications, and a @code{Save&Exit} (@kbd{@key{Meta}-X})
command, which saves the modified documents before quitting.

This choice of shortcuts could surprise you. Wouldn't @samp{Quit} be a
much better candidate for @kbd{@key{Control}-Q}? Well, experience shows that
the most common operation is closing a document rather than quitting the
editor. If there is just one document, the two operations coincide (this is
typical, for instance, when you use @code{ne} for writing electronic mail), and
if there are many documents, it is far more common to close a single document
than all the existing documents.

If you want to load a file, you may use the @code{Open} command, which can
be activated by pressing @kbd{@key{Control}-O}, by choosing the @samp{Open...}
item of the @samp{File} menu, or by typing it on the command line (as in the
previous case). You will be prompted with a list of files and directories in
the current working directory. (You can tell the directory names because they
end with a slash; they will also appear in a bold face if your terminal
allows it.) You can select any of the file names by using the
cursor keys, or any other movement key. Pressing an alphabetic key will
move the cursor to the first entry after the cursor that starts with the
given letter. When the cursor is positioned over the file you want to
open, press @key{Return}, and the file will be opened. If instead
you move to a directory name, pressing @key{Return} will display the
contents of that directory.

You can also escape with @key{f1}, @key{Escape} or
@key{Escape}-@key{Escape}  and manually type the file name on the command
line (or escape again, and abort the @code{Open} operation). If you escape
with @key{Tab} instead, the file or directory under the cursor will be
copied to the input line, where you can modify it manually. @code{ne} also
has file name completion features activated by @key{Tab} (@pxref{The Input
Line}).

When you want to save a file, just use the command @code{Save}
(@kbd{@key{Control}-S}). It will use the current document name or will
ask you for one if the current document has no name. @code{SaveAs}, on the
other hand, will always ask for a new name before saving the file.
@code{SaveAll} will save all modified documents. If the file you are
saving a document to has changed since you last loaded or saved it,
perhaps because another user updated it while you were editing,
@code{ne} will warn you before overwriting the file.

If @code{ne} is interrupted by an external signal (for instance, if your
terminal crashes), it will try to save your work in some emergency files.
These files will have names similar to your current files, but they will
have a pound sign @samp{#} prefixed to their names.
@xref{Emergency Save}.


@node Editing
@section Editing
@cindex Deleting characters
@cindex Deleting lines
@cindex Undeleting lines
@cindex Block operations
@cindex Clip usage
@cindex Multiple documents

An editor is presumably used for editing text. If you decide not to edit text, you
probably don't want to use @code{ne}, because that's all it does---it edits text.
It does not play @code{Tetris}. It does not evaluate recursive
functions. It does not solve your love problems. It just allows you to
edit text.

The design of @code{ne} makes editing extremely natural and straightforward.
There is nothing special you have to do to start editing once you've
started @code{ne}. Just start typing, and the text you type shows up in
your document.

@code{ne} provides two ways of deleting characters: the @key{Backspace} key
(or @kbd{@key{Control}-H}, if you have no such key) and the @key{Delete}
key. In the former case you delete the character to the left of the
cursor, while in the latter case you delete the character just under the
cursor. This is in contrast with many @sc{un*x} editors, which for
unknown reasons decide to limit your ways of destroying
things---something notoriously much funnier than creating. (See
@ref{DeleteChar} and @ref{Backspace}.)

If you want to delete a line, you can use the @code{DeleteLine} command, or
@kbd{@key{Control}-Y}. A very nice feature of @code{ne} is that each time a
nonempty line is deleted, it is stored in a temporary buffer from which it can
be undeleted via the @code{UndelLine} command or @kbd{@key{Control}-U}. (See
@ref{DeleteLine} and @ref{UndelLine}.)

If you want to copy, cut, paste, shift or erase a block of text, you have to
set a mark. This is done via the @code{Mark} command, activated by
choosing the @samp{Mark Block} item of the @samp{Edit} menu, or by
pressing @kbd{@key{Control}-B} (think ``block''). This command
sets the mark at the current cursor position. Whenever the mark is set, the text
between the mark and the cursor can be cut, copied or erased. Note that
by using @kbd{@key{Control}-@@} you can set a @emph{vertical} mark
instead, which allows you to mark rectangles of text. Whenever a mark
has been set, either an @samp{M} appears on the command line or a
@samp{V} appears if the mark is vertical. If you forget where the mark
is currently, you can use the @samp{Goto Mark} menu item of the
@samp{Search} menu to move the cursor to it.

The block of text you cut or copy is saved in a @dfn{clip}, which you can
@samp{Paste} somewhere else in your document, or save it
to a file with the @samp{Save Clip...} menu
item of the @samp{Edit} menu. You can also load a file directly into a clip with
@samp{Open Clip...}, and @samp{Paste} it anywhere. All such operations act on the
@dfn{current clip}, which is by default the clip 0. You can change the current
clip number with the @code{ClipNumber} command. @xref{ClipNumber}.

One of the most noteworthy features of @code{ne} is its @dfn{unlimited
undo/redo} capability. Each editing action is recorded, and can be played
back and forth as much as you like. Undo and redo are bound to the function
keys @key{f5} and @key{f6}.

Another interesting feature of @code{ne} is its ability to load an
unlimited number of documents. If you activate the @code{NewDoc} command
(using the @samp{Document} menu or the command line), a new, empty
document will be created. You can switch between your documents
with @key{f2} and @key{f3}, which are bound to the
@code{PrevDoc} and @code{NextDoc} commands. If you have a lot of
documents, the @samp{Select...} menu item (@key{f4}) prompts you with
the list of names of currently loaded documents and allows you to
choose directly which to edit. In that list, names of documents with
unsaved changes will be bold. You can also change their relative order
in that list with the @key{f2} and @key{f3} keys.


@node Basic Preferences
@section Basic Preferences
@cindex Preferences
@cindex Flags
@cindex Insert mode
@cindex Automatic preferences
@cindex Virtual Extensions

@code{ne} has a number of @dfn{flags} that specify alternative
behaviors, the most prototypical example being the @dfn{insert} flag,
which specifies whether the text you type is inserted into the existing text
or replaces it. You can toggle this flag with the @samp{Insert} menu
item of the @samp{Prefs} menu, or with the @key{Insert} key of your
keyboard. (@dfn{Toggle} means to change the value of a flag from true to
false, or from false to true; @pxref{Insert}.)

Another important flag is the @dfn{free form} flag, which specifies
whether the cursor can be moved beyond the right end of each line of
text or only to existing text (a la @code{vi}). Programmers usually
prefer non free form editing; text writers seem to prefer free form. See
@ref{FreeForm} for some elaboration. The free form flag can be set with
the @samp{Free Form} menu item of the @samp{Prefs} menu.

At this point, we suggest you explore by trial and error the other
flags of the @samp{Prefs} menu, or try the @code{Flags} command (@pxref{Flags}),
which explains all the flags and the commands that operate on
them. We prefer spending a few words discussing @dfn{automatic
preferences} or @dfn{autoprefs}, and @dfn{default preferences} or @dfn{defprefs}.

Having many flags ensures a high degree of flexibility, but it can turn
editing into a nightmare if you have to turn on and off dozens of flags
for each different kind of file you edit. @code{ne}'s solution is to
load your default preferences whenever @code{ne} is run before loading
any file, then additionally set your stated preferences automatically
for each @dfn{file type} as files are loaded. A file's type is determined
by the @dfn{extension} of its file name, that is, the last group of letters
after the last dot. For instance, the extension of @file{ne.texinfo} is
@samp{texinfo}, the extension of @file{source.c} is @samp{c}, and the
extension of @file{my.txt} is @samp{txt}.

Thus, when you select the @samp{Save Def Prefs} menu item or the
@code{SaveDefPrefs} command, a special preferences file named
@file{.default#ap} is saved. In addition to other preferences, this file also
includes a small set of preferences which are global to @code{ne} rather than
specific to particular document types. These preferences are: @code{FastGUI},
@code{RequestOrder}, @code{StatusBar} and @code{VerboseMacros};
@pxref{FastGUI}, @xref{RequestOrder}, @xref{StatusBar}, and
@xref{VerboseMacros}. These extra preferences are not saved by the
@code{SaveAutoPrefs} command.

By contrast, whenever you select the @samp{Save AutoPrefs} menu item, @code{ne} saves
the flags of your current document to be used when
you load other files with the same extension.
These @dfn{autoprefs} are saved in a file in your @file{~/.ne}
directory. This file has the same name as the extension of the current
document with @samp{#ap} appended to it. It contains all the commands
necessary to recreate your current document's flag settings. Whenever
you open a file with this file name extension, @code{ne} will
automagically recreate your preferred flag settings for that file type.
(There is a flag that inhibits the process; @pxref{AutoPrefs}.)

Similar to preference flags, the current syntax definition is specific to the current
document type, so it also is saved in autoprefs files by the
@code{SaveAutoPrefs} command or @samp{Save AutoPrefs} menu; it is not
saved in the @file{.default#ap} file.

Note that a preferences file---whether @file{.default#ap} or an AutoPrefs file---
is just a macro (as described in the following section). Thus, it can be edited manually if necessary.

Some files have no extension, but the file type can be discerned by simple
examination. Consider for example a file named @file{example} which contains XML.
You may reasonably expect it to be treated as an @file{.xml} file rather than
a generic file. For the purposes of applying automatic preferences and
syntax definitions, @code{ne} provides a mechanism for overriding a wrong or
missing extension with a @dfn{virtual extension} based on a document's
contents. You do this by creating a @file{~/.ne/.extensions} file which is
fully described in the @ref{Virtual Extensions} section.


@node Basic Macros
@section Basic Macros
@cindex Macro definition
@cindex Recording a macro
@cindex Saving a macro
@cindex Interrupting a macro
@cindex Interrupt character
@cindex Caching a macro
@cindex Unloading macros
@cindex Executing a macro
@cindex Comments in a macro

Very often, the programmer or the text writer has to repeat some complex
editing action over a series of similar blocks of text. This is where
@dfn{macros} come in.

A @dfn{macro} is a stored sequence of commands. Any sequence of commands
you find yourself repeating is an excellent candidate for being made
into a macro. You could create a macro by editing a document that only
contains valid @code{ne} commands and saving it, but by far the easiest way to create
a macro is to have @code{ne} record your actions. @code{ne} allows you
to record macros and then play them (execute the commands they contain)
many times. You can save them on disk for future use, edit them, or bind
them to any key. You could even reconfigure each key of your keyboard to
play a complex macro if you wanted to.

@code{ne} can have any number of named macros loaded at the same time.
In addition, each document can also have one unnamed macro in its @dfn{current macro} buffer.
Named macros are typically loaded from files, while each document's
current macro buffer is where your recorded macro is held before you
save it, play it, or record over it.

Recording a macro is very simple. The keystroke @kbd{@key{Control}-T}
starts and stops recording a macro.  When you start recording a macro,
@code{ne} starts recording all
your actions (with a few exceptions). You can see that you are recording
a macro if an @samp{R} appears on the status bar. After you stop the
recording process (again using @kbd{@key{Control}-T}), you can play the
macro with the @samp{Play Once} item of the @samp{Macros} menu or with
the @key{f9} key. If you want to repeat the action many times, the
@code{Play} command allows you to specify a number of times to repeat
the macro. You can always interrupt the macro's execution with
@kbd{@key{Control}-\}.

A recorded macro has no name. It's just an anonymous sequence of
commands associated with your current document. It will go away when you
record another macro, close the document, or exit @code{ne}. If you want to save your
recorded macro for future use, you can give it a name and save it with
the @samp{Save Macro...} menu item or the @code{SaveMacro} command.
The macro is saved as a regular text file in your current directory by default or
whatever directory you specify when prompted for the macro's name. If
you save it in your @file{~/.ne} directory then it will be easy to
access it later from any other directory. The @samp{Open Macro...} menu item
and the @code{OpenMacro} command load a macro from a file into the
current document's buffer just as if you had just @code{Record}ed it.

The current setting of your @code{VerboseMacros} flag determines whether
long or abbreviated command names are used when saving a macro. For your
convenience, @code{SaveMacro} will also convert sequences of
@code{InsertChar} commands into single---usually much more readable---
@code{InsertString} commands, but only if all the inserted characters are
simple printable characters, and only if there are no subsequent @code{Undo}
commands or macro invocations.

Any macro can be loaded from a file and played with the @samp{Play Macro...}
menu item or the @code{Macro} command. (This won't modify the recorded
anonymous macro that may be in the @dfn{current macro} buffer;
@code{OpenMacro} does that.) Useful macros can be permanently bound to a
keystroke as explained in @ref{Key Bindings}. Moreover, whenever a
command line does not specify one of @code{ne}'s built in commands, it is
assumed to specify the name of a macro to execute. Thus, you can execute
macros just by typing their file names at the command line. Include a path if the macro
file's directory is different from your current directory or your
@file{~/.ne} directory.

If the first attempt to open a macro fails, @code{ne} checks for a macro
with the given name in your @file{~/.ne} directory. This allows you
to program simple extensions to @code{ne}'s command set. For instance, all
automatic preferences macros---which are just specially named macros
that contain only commands to set preferences flags---can be executed
just by typing their names. For example, if you have an automatic
preference for the @samp{txt} extension for example, you can set
@code{ne}'s flags exactly as if you had loaded a file ending with
@samp{.txt} by typing the command @code{txt#ap}.

In general, it is a good idea to save frequently used macros in
@file{~/.ne} so that you can invoke them by name without specifying
a path regardless of your current directory. On the other hand, if you
have a macro that is customized for one document or a set of documents
that you store in one directory, then you might want to save the
macro in that directory instead. If you do, then you would want to
@code{cd} to that directory before you start @code{ne} so that you can
access that macro without specifying a path.

If your macro has the same name as one of @code{ne}'s built-in commands,
you can only access it with the @code{Macro @var{name}} command.
Built-in command names are always searched before the @code{ne} command
interpreter looks for macros.

The system administrator may make some macros available from
the @file{macros} subdirectory of @code{ne}'s global directory. @xref{Arguments}.

Since loading a macro each time it is invoked would be a rather slow and
expensive process, once a named macro has been executed it is cached internally.
Subsequent invocations of the named macro will use the cached version.

@noindent @strong{Warning:} while path and file names are case sensitive
when initially loading macros, loaded macro names are @emph{not} case
sensitive or path sensitive. @code{ne} only caches the file name of an
already loaded macro, not the path, and it uses a case insensitive
comparison when resolving command names. As such, if you invoke @file{~/foobar/MyMacro}, @code{ne}
remembers it with the case-insensitive name @file{mymacro}; a subsequent
call for @file{/usr/MYMACRO} will instead find and use the cached version
of @file{~/foobar/MyMacro}. You can clear the cache by using the
@code{UnloadMacros} command. @xref{UnloadMacros}.

The behaviour of macros may vary with different preferences. If the user
changes the @code{AutoIndent} and @code{WordWrap} flags, for example, new lines and new
text may not appear in the same way they would have when a macro was
recorded. Good general purpose macros avoid such problems by using the
@code{PushPrefs} command first. This preserves the user's preferences.
Then they set any preferences that could affect their behaviour. Once
that is taken care of they get on with the actual work for which they
were intended. Finally, they use the @code{PopPrefs} command to restore
the user's preferences. Note that if a macro is stopped before it
restores the preferences (either by the user pressing
@kbd{@key{Control}-\} or by a command failing) then dealing with the
changed preferences falls to the user.

Any changes made to a document by a macro are recorded just as if you had
entered the commands yourself. Therefore you can use the @code{Undo} command
to roll back those changes one at a time. This can be useful especially when
developing macros, but you may want to be able to undo all the changes made
by a macro with a single @code{Undo} command. The @code{AtomicUndo} command
makes this possible. If you add @code{AtomicUndo +} at the start of your
macro and @code{AtomicUndo -} at the end, then the @code{Undo} and
@code{Redo} commands will handle all changes made by your macro atomically,
i.e., as if they had been made by a single command, even if your macro
calls other macros which could themselves contain matching @code{AtomicUndo +}
and @code{AtomicUndo -} commands. @xref{AtomicUndo}.

Any line in a macro that starts with a non-alphabetical character
is considered a comment, so you can add comments to a macro by starting
a line with @samp{#}. Recorded macros sometimes have comments added to them
indicating calls to other macros.

Macros can operate across multiple documents, by using the @code{NextDoc} and
@code{PrevDoc} commands for example. When you stop recording, the unnamed
macro is associated with the current document, replacing that document's
prior unnamed macro.

You can cancel in-progress macro recording with the @code{Record 0}
command, or by selecting @code{Record Cancel} from the @code{Macro} menu.

You can append additional recorded commands to your document's current
macro with the @code{Record 1} command, or by selecting @code{Record Append}
from the @code{Macro} menu.



@node More Advanced Features
@section More Advanced Features
@cindex UTF-8 support
@cindex Bookmarks
@cindex Automatic Completion
@cindex Automatic Bracket Matching
@cindex MS-DOS files
@cindex File requester
@cindex Binary files
@cindex Executing @sc{uni*x} commands

@subsection UTF-8 support
@code{ne} can load and
manipulate UTF-8 files transparently, in particular on systems that
provide UTF-8 I/O. @xref{UTF-8 Support}.

@subsection Bookmarks
It often happens that you have to browse through a file, switching
frequently between a small number of positions. In this case, you can use
@dfn{bookmarks}. There are up to ten bookmarks per document, each
designated by a single digit, with the default being @samp{0}. You can set
them with the @code{SetBookmark} command, and you can return to any set
bookmark with the @code{GotoBookmark} command. Also, @code{ne} sets an
automatic bookmark (designated by @samp{-}) at your current position in a
document whenever you use the @code{GotoBookmark} command. You can use
a @code{GotoBookmark -} command to return to the location of the previous
@code{GotoBookmark} command. Doing so will reset the automatic bookmark,
so that subsequent @code{GotoBookmark -} commands will switch between
those two locations. The special parameters @samp{+1} and @samp{-1}
indicate the next or previous set bookmark in conjunction with
@code{GotoBookmark} and @code{UnsetBookmark}, but reference the next or
previous unset bookmark when used with @code{SetBookmark}. A sequence of
@code{GotoBookmark +1} commands lets you easily cycle through all your set
bookmarks. Finally, the special parameter @samp{?} causes @code{SetBookmark}
and @code{GotoBookmark} to prompt you for a bookmark designation. This prompt
includes an indication of which bookmarks are already set for the current
document. @xref{SetBookmark}, @ref{GotoBookmark}, and
@ref{UnsetBookmark}. Note that in the default configuration no key binding
is assigned to these commands. If you use them frequently, you may want to
change the key bindings. @xref{Key Bindings}.

@subsection Automatic Completion
The @code{AutoComplete} command helps you extend a given prefix with matching
words from your open documents.  You can specify the @code{AutoCompete} command
and prefix on the command line, or you can enter the prefix directly into your
document and activate the @code{AutoComplete} command. With the cursor at the
right end of your prefix, activate the @code{AutoComplete} command by entering
either the @key{Escape}-@key{Tab} or the @key{Escape}-@key{I} key sequence, or
the @kbd{@key{Control}-@key{META}-@key{I}} key combination, or by selecting
@code{AutoComplete} from the @code{Extras} menu.

If the prefix can be extended
unambiguously, the extension will be immediately inserted into your
document (this is the case, for instance, if only one word matches the
prefix), and a message will tell you whether the extension is an actual word
or just the longest possible extension (for instance, if you expand
@samp{fo} and your document contains @samp{foobar} and @samp{foofoo} then the
partial match will be @samp{foo}). Otherwise, @code{ne} presents you with
a list of all matching words: choose the one you want and press
@key{Return}, to select it; otherwise, press @key{f1}, @key{Escape} or
@key{Escape}-@key{Escape} to cancel the completion operation.

The current
state of the @code{CaseSearch} flag determines whether the prefix match is
case sensitive. Any matching words which only exist in other open
documents but not the current one are displayed in bold with an asterisk;
think of that as a warning that if you select one of these bold words you
will introduce a new word into your current document. Plain words already
exist somewhere in your current document. @xref{AutoComplete}, and
@ref{CaseSearch}.

@subsection Automatic Bracket Matching
Unless you tell it not to (with the @code{AutoMatchBracket} command),
@code{ne} will highlight any recognized bracket that matches the
bracket your cursor is on if that matching bracket is currently visible on
your screen. Recognized bracket pairs are @samp{@{@}}, @samp{()}, @samp{[]},
@samp{<>}, and @samp{`'}. @xref{AutoMatchBracket}.

@subsection MS-DOS files
@code{ne} will detect automagically the presence of MS-DOS line terminators
(CR/LFs) and set the CR/LF flag. When the file will be saved, the
terminators will be restored correctly. You can change this behaviour
using the @code{PreserveCR} and @code{CRLF} commands. @xref{PreserveCR},
and @ref{CRLF}.

@subsection Binary files
@code{ne} allows a simplified form of @dfn{binary editing}. If the
binary flag is set, only NULLs are considered newlines when loading or
saving. Thus, binary files can be safely loaded, modified and saved.
Inserting a new line or joining two lines has the effect of inserting or
deleting a NULL. Be careful not to mismatch the state of the binary flag
when loading and saving the same file.

@subsection File requester
The @code{NoFileReq} command deactivates the file requester. It is
intended for ``tough guys'' who always remember the names of their files and can
type them at the speed of light (maybe with the help of the completer,
which is activated by the @key{Tab} key; @pxref{The Input Line}).

@subsection Executing @sc{un*x} commands
There are three ways to execute @sc{un*x} commands from within @code{ne}.
The @code{System} command can run any @sc{un*x} command; you
will get back into @code{ne} as soon as the command execution terminates.
@xref{System}. The @code{Through} (@kbd{@key{Meta}-T}) command (which can be found in the
@samp{Edit} menu), however, is much more powerful; it cuts the current
block, passes it as standard input to any @sc{un*x} command, and pastes the
command's output at the current cursor position. This provides a neat
way to pass a part of your document through one of @sc{un*x}'s many
@dfn{filter commands} (commands that read from standard input and write
to standard output, e.g., @code{sort}). @xref{Through}. Finally, you can use the
@code{Suspend} (@kbd{@key{Control}-Z}) command to temporarily stop @code{ne} and
return to your command shell. @xref{Suspend}.

@subsection Advanced key bindings
@code{ne} allows you to associate any keystroke with any command, both
built-in commands (with or without parameters) and macros. These associations
are refered to as @dfn{key bindings}, which you define in your
@code{~/.ne/.keys} file. The @code{KeyCode} command allows you to see the key
code @code{ne} sees in response to any key or key combination on your
keyboard. It also shows the command string currently associated with that key
code. This is described in @ref{Key Bindings}.


The following chapters provide an exhaustive list of the remaining features of @code{ne}.
@xref{Reference}.



@node Reference
@chapter Reference

In this chapter we shall methodically overview each part of @code{ne}. It
is required reading for becoming an expert user because some commands
and features are not available through menus.

@menu
* Arguments::
* The Status Bar::
* The Input Line::
* The Command Line::
* The Requester::
* Syntax Highlighting::
* Menus::
* Regular Expressions::
* Automatic Preferences::
* Emergency Save::
* UTF-8 Support::
@end menu


@node Arguments
@section Arguments
@cindex Arguments
@cindex Global Directory
@cindex Startup macro
@cindex Skipping configuration files
@cindex Setting configuration file names

The main arguments you can give to @code{ne} are the names of files you
want to edit. They will be loaded into separate documents. If you
specify @code{--help} or @code{-h} anywhere on the command line, a simple help text
describing @code{ne}'s arguments will be printed.

The @code{+@var{N}} option causes @code{ne} to advance to the @var{N}th
line of the next document loaded. This option is fairly common among
editors and text display programs like @code{vi} and @code{less}. The
@var{N} itself is optional. Without it, a bare @code{+} on the command
line causes @code{ne} to advance to the last line of the first
document. You can specify a line and column as @code{+N,M}. Any
non-digit can be used to separate the @var{N} from the @var{M}. As it
only affects the next document loaded, it can appear multiple times on
the command line.

The @code{--binary} option causes @code{ne} to load the next document
in binary mode. Binary mode treats the normal line termination
characters as any other character and only breaks lines on NULL
characters. Like @code{+N,M}, @code{--binary} only affects the next
document loaded, and it can appear multiple times on the command line.
See @ref{Binary}.

The @code{--read-only}/@code{--readonly}/@code{--ro} option causes @code{ne} to load the next named file
into a read-only document. You can't modify a read-only
document without first taking special action such as turning off the read-only
flag. You can still @code{Save} (@ref{Save}) a read-only document to a
file if the file's permissions allow it, but @code{ne} will prompt you
before attempting to save a document marked read-only.
The @code{--read-only} option only affects the next document loaded,
so it can appear multiple times on the command line. A document's
read-only flag is automatically set when a file is loaded if the
corresponding file is not writable (as determined by the @code{access()}
system call) regardless of whether the @code{--read-only} option is used. See
@ref{ReadOnly}.

The @code{--no-config}/@code{--noconfig} option skips the reading of the key
bindings and menu configuration files (@pxref{Configuration}). This is
essential if you are experimenting with a new configuration and you make
mistakes in it.

The @code{--prefs @var{extension}} option makes @code{ne} load a specified
set of automatic preferences, that is, those associated with the provided
extension, instead of the default ones, before loading the first file.
It can be useful, for instance, when piping a file into @code{ne} or when
reading from named pipes, as in those cases there is no file extension
from which @code{ne} can guess the correct preferences. Note that preferences
are cloned from the current document when a new document is created, so if
you open a number of files without extension this option will propagate
to all of them.

The @code{--macro @var{filename}} option specifies the name of a
macro that will be started just after all documents have been loaded. A
typical macro would move the cursor to a certain line.

The @code{--keys @var{filename}} option and the @code{--menus
@var{filename}} option specify a name different from the default one
(@file{.keys} and @file{.menus}, respectively) for the key bindings and
the menu configuration files. Note that @code{ne} searches for these
files first in the current directory, and then in your @file{~/.ne}
directory.

The @code{--ansi} and the @code{--no-ansi}/@code{--noansi} options manage
@code{ne}'s built-in ANSI sequences. Usually @code{ne} tries to retrieve
from your system some information that is necessary to handle your
terminal. If for some reason this is impossible, you can ask @code{ne}
to use a built-in set of sequences that will work on many terminals
using the @code{--ansi} option (to be true, @code{ne} can be even
compiled so that it uses directly the built-in set, but you need not
know this). If you want to be sure (usually for debugging purposes) that
@code{ne} is not using the built-in set, you can specify
@code{--no-ansi}.

The @code{--no-syntax} option disables @code{ne}'s normal syntax
highlighting capability. For most editing situations, this would be
unnecessary, but for extremely large files it may be helpful. Syntax
highlighting incurs small memory usage and processor overhead penalties
for each line of text. The @code{--no-syntax} option eliminates that
overhead. Note that files longer than ten million bytes will have
syntax highlighting disabled by default, but it is possible to re-enable it.
@xref{Syntax Highlighting}.

The @code{--utf8} and @code{--no-utf8} options can be used to
force or inhibit UTF-8 I/O, overriding the choice imposed by the system
locale. Note, however, that in general it is more advisable to set the
@code{LANG} environment variable to a locale supporting UTF-8 (you can
usually see the locale list with @code{locale -a}). @xref{UTF-8 Support}.

If you need to open a file whose name starts with @samp{--}, you can put
@samp{--} before the filename, which will skip command recognition for
the next word.

You can use I/O redirection to pipe the output of other commands into your
first document. For example,

@example
  ls -l | ne file1.txt --read-only file2.txt
@end example

will open three documents: an unnamed document containing the output of
the @code{ls -l} command, the contents of @file{file1.txt}, and the contents
of @file{file2.txt} with the read-only flag set.

It's possible to apply the @code{--binary}, @code{--read-only}, and
@code{+N,M} options to the piped unnamed document by referencing it as a
single @code{-}. Only the first such file name will reference the piped
document (even if it isn't the first file name on the command line).
Subsequent dashes will be considered normal file names. If you want the first
dash to be treated like a normal file instead of a reference to the piped
document, prefix the dash with @samp{--}. Consider these two command lines:

@example
  ls -l | ne --read-only +3,8 - file1.txt -
  ls -l | ne file1.txt -- - --read-only +3,8 -
  ls -l | ne --binary file1.txt --read-only -- -
@end example

All three of these commands open @code{ne} with three documents: the output
of the @code{ls -l} command will be in the first unnamed document, the
contents of @file{file1.txt} will be in the second document, while the third
document will contain the contents of the file @file{-} (or an empty document
with that name if there is no such file). The first and second commands do
exactly the same thing: the unnamed first document is marked read-only and
the cursor is positioned on line 3 column 8, while the other two document are
opened normally. In the case of the third command, @file{file1.txt} is opened
in binary mode, the document named @file{-} is marked read-only, while the
first, unnamed, document---which is not referenced on the command line---with
the output from @code{ls -l} is opened normally.

Finally, @code{ne} has a @dfn{global directory} where the system
administrator can store macros, default preferences, and syntax
definitions for all users of the system. The location of this directory
is defined when @code{ne} is built, but you can override it by creating
and exporting the @code{NE_GLOBAL_DIR} environment variable prior to
invoking @code{ne}. If you load no files when you start @code{ne}, or
if you invoke the @code{About} command, it will display a splash
screen. The last line on that screen shows the global directory
@code{ne} is using, if it exists, or an error message otherwise.


@node The Status Bar
@section The Status Bar
@cindex Status bar
@cindex Line and column numbers
@cindex Fast GUI

The last line of the screen, the @dfn{status bar}, is reserved by
@code{ne} for displaying some information about its internal state.
Note that on most terminals it is physically impossible to write a
character on the last column of the last line, so we are not
stealing precious editing space.

The status bar looks more or less like this:

@example
L:      31  C:      25   12% iabcwfpvurt!MRPC@@8*       20 /foo/bar
@end example

The numbers after @samp{L:} and @samp{C:} are the line and column of the
cursor position. The first line and the first column are both number
1. Then, @code{ne} shows the percentage of lines before the current line
(it will be 0% on the first line, and 100% on the last line).

Following that are a sequence of letters or
dashes. These indicate the status of a series of flags which we shall
look at later.

The hexadecimal digits following the flags give the code for the
character at the cursor, and are displayed optionally (@pxref{HexCode}).
If your cursor is at or beyond the right end of the current line, the
code disappears.

The file name appearing after the character code is the file name of
the current document. The left end of very long file names may be
truncated to keep the right end visible. Of course,
@code{ne} is keeping track internally of the complete file name. It
is used by the @code{Save} command and as the default input for the
@code{SaveAs} command. @xref{Save}, and @ref{SaveAs}.

The displayed line and column numbers, the percentage indicator and the
character code change when the cursor moves. This fact can really slow
down cursor movement if you are using @code{ne} through a slow
connection. If you find this to be a problem, it is a good idea to turn
off the status bar using either the @samp{Status Bar} menu item of the
@samp{Prefs} menu or the @code{StatusBar}
command. @xref{StatusBar}. Alternatively you can turn on the fast GUI
mode using either the @samp{Fast GUI} menu item of the @samp{Prefs} menu
or the @code{FastGUI} command (@pxref{FastGUI}). In fast GUI mode the
location of the mark is not highlighted, and 
status bar is not draw in reverse, so some additional optimization can
be done when refreshing it.

The letters after the line and column number represent the status of the flags
associated with the current document. Flags that are off display a
@samp{-} instead of a letter. Each flag also has an
associated command. The @code{Flags} command describes them all when
you don't have this manual handy. Here's the list in detail:

@table @samp

@item i
appears if the insert flag is true. @xref{Insert}.

@item a
appears if the auto indent flag is true. @xref{AutoIndent}.

@item b
appears if the back search flag is true. @xref{SearchBack}.

@item c
appears if the case sensitive search flag is true. @xref{CaseSearch}.

@item w
appears if the word wrap flag is true. @xref{WordWrap}.

@item f
appears if the free form flag is true. @xref{FreeForm}.

@item p
appears if the automatic preferences flag is true. @xref{AutoPrefs}.

@item v
appears if the verbose macros flag is true. @xref{VerboseMacros}.

@item u
appears if the undo flag is true. @xref{DoUndo}.

@item r
appears if the read only flag is true. @xref{ReadOnly}.

@item t or T
appears as @samp{t} if the tabs flag is true, @samp{T} if
the shifttabs flag is also true. @xref{Tabs}, @ref{ShiftTabs}.

@item d
appears if the deltabs flag is true. @xref{DelTabs}.

@item B or !
appears if the binary flag is true. @xref{Binary}.

@item !
appears in place of @samp{B} when not in binary mode
and the last line of the document is not empty (i.e. the last line of the
saved file would not be terminated).

@item M or V
appears if you are currently marking a block. @xref{Mark}.

@item V
can appear in place of @samp{M} if you are currently marking a vertical
block. @xref{MarkVert}.

@item R
appears if you are currently recording a macro. @xref{Record}.

@item P
appears if the PreserveCR flag is true. @xref{PreserveCR}.

@item C
appears if the CRLF flag is true. @xref{CRLF}.

@item @@
appears if UTF-8 I/O is enabled. @xref{UTF8IO}.

@item A/8/U
denotes the current document encoding---US-ASCII, 8-bit or UTF-8. @xref{UTF8}.

@item *
appears if the document has been modified since the last save, or if
the @code{Modified} command was issued to set this flag. @xref{Modified}.
This @samp{-} or @samp{*} may be underlined, which indicates the
corresponding file's modification time has changed since the current
document was loaded from or saved to that file.

@end table

Note that sometimes @code{ne} needs to communicate some message to you. The
message is usually written over the status bar, where it stays
until you do something. Any action such as moving the cursor or inserting a
character will restore the normal status bar.


@node The Input Line
@section The Input Line
@cindex Input line
@cindex Escaping an input
@cindex Immediate input
@cindex Long input
@cindex File name completion

The bottom line of the screen is usually occupied by the status bar
(@pxref{The Status Bar}). However, whenever @code{ne} prompts you for a
command or file name or asks you to confirm some action, the bottom line
becomes the @dfn{input line}. You can see this because a @dfn{prompt} is
displayed at the start of the line, suggesting what kind of input is
required. (Prompts always ends with a colon, so it is easy to
distinguish them from @dfn{error messages}, which overwrite the status
bar from time to time.)

@code{ne} uses the input line in two essentially different ways:
@dfn{immediate} input and @dfn{long} input. You can easily distinguish
between these two modes because in immediate input mode the cursor is
not on the input line, while for long input mode it is.

Immediate input is used whenever @code{ne} needs you to specify a simple
choice that can be expressed by one character (for example, @samp{y} or
@samp{n}). When you type the character, @code{ne} will immediately
accept and use your input. Most immediate inputs display a character
just after the prompt. This character is the default response, which is
used if you just press the @key{Return} key. Note that immediate input
is not case sensitive. Moreover, if a yes/no choice is requested,
@emph{anything} other than @samp{y} will be considered a negative
response.

Long input is used when a whole string is required. You can enter and
edit your response to long inputs like a line of text in a
document. Most key bindings related to line editing work on the command
line exactly as they do in a document. This is true even of custom key
bindings. Just edit as you are used to. Moreover, the you can paste the
first line of the current clip using the keystroke that is bound to the
@code{Paste} command, usually @kbd{@key{Control}-V}. If your long input
is longer than the screen width, the input line scrolls to accommodate
your text so you can input very long lines even on small
monitors. (There is a limit of 2048 characters.)

The default response to a long input is the response you gave to the
previous long input. Your @emph{first action} when presented with a long
input will either erase the default response or allow you to edit it. If
the first thing you type is a printing character, the default response
will be erased. Anything else (cursor movement for example) will allow
you to edit it further.

Long input also lets you access your previous long input responses with
the up and down cursor commands (or with wider movement commands, such
as start/end of file, page up/down, etc.). Once you find a previous
input you like, you can edit it further. Long input history is not
document specific, so you can recall any of your inputs regardless of
which document was active when you entered it. Furthermore, @code{ne}
saves the most recent long inputs in @file{~/.ne/.history} when you end
your @code{ne} session and loads them again when you begin another
@code{ne} session.

Invoking the @code{Find} command, usually bound to
@kbd{@key{Control}-F}, brings up a requester showing your prior inputs.
You can close the requester with the @key{Escape} key, replace your
input line with a highlighted prior entry with the @key{Enter} key, or
insert that prior entry into your input line with the @key{Tab} key.

When asked to input a number, you can choose between decimal, octal and
hexadecimal notation in the standard way: a number starting with
@samp{0} is considered in octal, a number starting with @samp{0x} is
considered in hexadecimal, and in all other cases decimal base is
assumed.

Whenever a file name is requested, you can type a partial file name and
@dfn{complete} it with the @key{Tab} key. @code{ne} will scan the
current directory (or the directory that you partially specified) and
search for the files matching your partial suggestion. The longest
prefix common to all such files will be copied to the input line
(@code{ne} will beep if no completion exists). It's easier done than
said---just try. If you press @key{Tab} again, you will be brought into
the file requester: only the files and directories matching your partial
specification will appear, and as usual you will be able to navigate and
select a file or escape. @xref{The Requester}.  Note that @code{ne}
considers the @emph{last word} on the input line the partial file name
to complete, no matter where the cursor is currently (you must use quotes
if the name contains spaces, even if it is the only item on the input line).

Complete long input with the @key{Return} key. You can cancel a long
input using @key{f1}, @key{Escape}, @key{Escape}-@key{Escape} or any key
that is bound to the @code{Escape} command. The effect will vary depending
on what your were requested to input, but the execution of the command
requiring the input will stop.




@node The Command Line
@section The Command Line
@cindex Command line

The command line is a typical (topical) way of controlling an editor on
character driven systems. It has some advantages over menus in terms of
access speed, but it is not desirable from a user interface point of
view. @code{ne} has a command line that should be used whenever strange
features have to be accessed, or whenever you want to use a command that
you are familiar with and that is not bound to any key.

You have two ways to access the command line: by activating the menu and
typing a colon (@samp{:}) or by typing @kbd{@key{Control}-K} (or any key
that is bound to the @code{Exec} command; @pxref{Exec}). The first
method will work regardless of any key binding configuration if you
activate the menus with the @key{Escape} key since that key cannot be
reconfigured. Of course, there is also a menu entry that does the same
job.

Once you activate the command line, the status bar will turn into an input
line (@pxref{The Input Line}) with a @samp{Command:} prompt waiting for you
to do a long input. In other words, you can now type any command (possibly
with arguments), and when you press @key{Return}, the command will be
executed.

If the command you specify does not appear in @code{ne}'s internal tables,
it is considered to be the name of a macro. @xref{Basic Macros}, for details.


@node The Requester
@section The Requester
@cindex Requester
@cindex File requester
@cindex Interrupting directory scanning
@cindex Help requester

In various situations, @code{ne} needs to ask you to choose one string
from several (where ``several'' can mean a lot).
For this kind of event, the @dfn{requester} is issued. The requester
displays the strings in as many columns as possible and lets you move
with the cursor from one string to another. The strings can fill many
screens, which are handled as consecutive pages. Most navigation keys
work exactly as in normal editing. This is true even of custom key
bindings. Thus, for instance, you can page up and down through the
list with @kbd{@key{Control}-P} and @kbd{@key{Control}-N} (in the standard keyboard
configuration).

A special feature is bound to printing characters: the requester
progressively advances to entries that match the characters you
type without regard to case. You can use @key{Backspace} to
incrementally undo your matched characters. This progressive matching
works in two modes which you can switch between on the fly with either
the @key{Insert} or @key{Delete} key. In the default mode, the cursor
indicating your current selection simply advances to the next matching
entry (if there is one). In the other mode, all entries which don't
match the characters you've entered are removed from the list so you
only see the matching entries. The @key{Backspace} key incrementally
returns them to your list as your match becomes less specific. You can
switch between the two modes as often as you wish while searching for
your desired entry. This lets you quickly navigate large lists to get
to the entries you really want.

One example of a requester is the list of commands appearing when you use
the @code{Help} command. Another is the list of document words matching
a prefix given to the @code{AutoComplete} command. A third example is
the file requester that @code{ne} issues whenever a file operation is
going to take place. In this case, pressing @key{Return} while on a
directory name will enter that directory and refresh the requester with
that directory's entries. Note also that, should the requester take too long to
appear, you can interrupt the directory scanning with
@kbd{@key{Control}-\}. However, the listing will likely be incomplete.

Yet another example of a requester is the list of documents you
currently have open. This requester is displayed when you use the
@code{Select...} entry from the @code{Documents} menu, or invoke the
@code{SelectDoc} command with the @key{f4} key. Documents with unsaved
changes will be bold (if your terminal supports bold) and marked with
an asterisk.

These documents are generally listed in the order they
were opened. However, in this requester you can reorder these documents
by using the keys bound to the @code{NextDoc} and @code{PrevDoc}
commands, usually @key{f2} and @key{f3}. Any document reordering and
selection will only take effect if you exit the requester with the
@key{Return} key. 

You can also save named documents and close unmodified documents without
leaving the @code{SelectDoc} requester by using the key bound to the
@code{Save} and @code{CloseDoc} commands respectively, usually
@kbd{@key{Control}-S} and @kbd{@key{Control}-Q}. You can't close the last
document this way because it would cause @code{ne} to exit.

Regardless of the type of requester, you can confirm your selection
with @key{Return} just as with the input line (@pxref{The Input Line}), or
you can escape the requester without making a selection with @key{f1}
or the @key{Escape} key (or whatever has been bound to the
@code{Escape} command).

Moreover, if you are selecting a file name through the requester there
is a third possibility: by escaping with the @key{Tab} key, the file or
directory name that the cursor is currently on will be copied to the
input line. This allows you to choose an existing name with @key{Tab}
and modify the name on the input line before hitting @key{Return}.

Note that there are two items that always appear at the top of a file
requester: @file{./} and @file{../}. The first one represents the
current directory and can be used to force a reread of the directory.
The second one represents the parent directory and can be used to move
up by one directory level.

The path to file names and directories selected through the requester
will be relative to the current directory, i.e. the directory you were
in when you invoked @code{ne}. The exception is when you've entered a
path on the command line that starts with a @key{/}, then hit @key{Tab}
to invoke the requester. In that case the path eventually returned by the
requester will be an absolute path. (Note that you can change the
current document's name from relative to absolute or absolute to
relative with the @code{NameConvert} command either on the command line
or from the @code{Extras} menu.)

All requesters present their selections by default in ``row major order,''
which means the second string is on the same row as the first but to
its right, at the top of the second column, and so on across each row
before filling in the next row down. If you prefer your lists displayed in
``column major order''---the first, second, and third strings are in
the same column and each column is filled before starting on the next
column to the right---then use the @code{RequestOrder} command to
switch that preference. The setting will be stored in your default
preferences the next time you save them. See @ref{Preferences Commands}.


@node Syntax Highlighting
@section Syntax Highlighting
@cindex Syntax Highlighting

Syntax highlighting is particularly useful for programming language
text or other types of documents which have a strictly defined syntax.
Colors indicate different syntactic categories of text according to
the syntax definition in use.

Syntax definitions are stored in separate files. @code{ne} comes with a
suite of syntax definitions for many popular programming languages and
other common text file types.
When you load a file, @code{ne} selects the appropriate syntax
definition as determined by the filename extension in much the same way
autoprefs are loaded. (See @ref{Virtual Extensions} for ways to override
a file's extension based on file contents.)
It also contains a built-in table of common
filename extensions that share the same syntax definitions. For
example, both @samp{cbl}, and @samp{cob} files use the @samp{cobol}
definition. See the @ref{Syntax} command for the complete list of
built-in extension mappings.

If there is no matching syntax definition for the filename extension,
or if the document you are editing has no filename yet, or you just want
to try a different syntax definition, you can load and use the
syntax definition of your choice with the @code{Syntax} command. It
takes the syntax name as a parameter. For example, the name ``@code{c}''
works for C syntax files with extensions @samp{.c}, @samp{.h},
@samp{c++}, etc. @code{ne} searches for the specified syntax definition
file in the @samp{syntax} subdirectory of your @file{~/.ne} directory
first. If not found there, @code{ne} then looks in the @samp{syntax}
subdirectory of @code{ne}'s global directory for the syntax definition
file. @xref{Arguments}.

With no parameter, the @code{Syntax} command prompts you for a syntax
to load, the offered default being the currently loaded syntax if there is one.
Use the @key{Tab} key at that prompt to get a list of available syntax
recognizers.

One syntax definition you may find useful for any type of text file is
called simply @samp{tabs}. It highlights the @sc{tab}s in your text so
you can distinguish them from regular spaces.

You can create your own syntax definitions and store them in your
@file{~/.ne/syntax} directory (actually, modifying the colors of an
existing definition is much easier; @pxref{Hints and Tricks}). A complete
explanation of syntax specifications is beyond the scope of this document,
but the existing definition files should prove to be useful examples. In
particular, the @file{syntax/c.jsf} file contains some particularly
helpful comments. Syntax definition files have a @samp{.jsf} extension. Do
not include that extension when using the @code{Syntax} command.

Your own syntax recognizers will be preferred over the global recognizers.
If you use the @key{Tab} key at the syntax prompt to display the requester
of extant recognizers, yours will be marked with an asterisk and bold if
your terminal supports that.

Syntax highlighting does incur a slight penalty in memory used per line of
text, and it also consumes some CPU resources. For small to medium sized
files you'll probably never notice. But for extremely large files---on
the order of the size of your system's RAM---the difference could be
significant. If you invoke @code{ne} with the @code{--no-syntax}
parameter, @code{ne} will disable the syntax highlighting mechanism
entirely, freeing up the memory and CPU otherwise consumed. (Note that
if you are that tight on memory, you may need to disable the undo
buffer as well. @xref{DoUndo}.) On the other hand, @code{ne} will silently
disable syntax highlighting on files longer than ten million bytes, but
you can force it using the @code{Syntax} command.

Note that there is a basic difference between these two cases: when you
use the @code{--no-syntax} parameter, the additional memory is not
allocated at all, and syntax highlighting cannot be enabled without
restarting @code{ne}. On the contrary, the automatic disabling for long
files keeps only @code{ne} from computing the actual highlighting, and it
can be overriden as explained above.

@code{ne} uses code from another editor---the GPL-licensed
@code{joe}---for its syntax highlighting capabilities. Because of this fact, the
syntax definition files are identical, even to the @samp{.jsf}
extension, which is an acronym for ``Joe's Syntax File''. It's possible
that if both @code{joe} and @code{ne} are installed on your system that
they share the same syntax file directory.




@node Menus
@section Menus
@cindex Menus

@code{ne}'s menus are extremely straightforward. The suggested way of
learning their use is by trial and error, with a peek here and there
at this manual when some doubts arise.

You activate menus with the @key{f1} key, or in case your keyboard does
not have such a key, @key{Escape}, @key{Escape}-@key{Escape} or any key
that is bound to the @code{Escape} command. Move around the menus pressing
with the cursor keys, the @key{Page Up} and @key{Page Down} keys (which move to the first or
last menu item in a menu), and the @key{Home} and @key{End} keys (which move to the first or
last menus). You can also move around menus and menu items by
pressing the alphabetic keys; a lower case letter will move to the first
item in the current menu whose name starts with the given letter; an upper
case letter will move to the first menu whose name starts with the given
letter.

If you've activated the menus and you want to switch immediately to the command line,
press the @key{:} key. The menus will clear and you'll find yourself on the command
line. @xref{The Command Line}.

Each menu item of @code{ne}'s standard menu corresponds to a
single command. In explaining what each menu item allows you to
do, we shall simply refer you to the section that explains the command
relative to the menu item.

If you plan to change @code{ne}'s menu (@pxref{Changing Menus}), you should
take a look at the file @file{default.menus} that comes with @code{ne}'s
distribution. It contains a complete menu configuration that clones the standard
one.

@menu
* File::
* Documents::
* Edit::
* Search::
* Macros::
* Extras::
* Navigation::
* Prefs::
@end menu


@node File
@subsection File

The File menu contains standard items that allow loading and saving
files. Quitting @code{ne} (which doesn't save changes) or exiting
@code{ne} (which does save changes) is also possible.

@table @samp

@item Open@dots{}
@xref{Open}.

@item Open New@dots{}
@xref{OpenNew}.

@item Save
@xref{Save}.

@item Save As@dots{}
@xref{SaveAs}.

@item Save All
@xref{SaveAll}.

@item Quit Now
@xref{Quit}.

@item Save&Exit
@xref{Exit}.

@item About
@xref{About}.

@end table



@node Documents
@subsection Documents

The Documents menu contains commands that create new documents, destroy
them, and browse through them.

@table @samp

@item New
@xref{NewDoc}.

@item Clear
@xref{Clear}.

@item Close
@xref{CloseDoc}.

@item Next
@xref{NextDoc}.

@item Prev
@xref{PrevDoc}.

@item Select@dots{}
@xref{SelectDoc}.

@end table



@node Edit
@subsection Edit

The Edit menu contains commands related to cutting and pasting text.

@table @samp

@item Mark Block
@xref{Mark}.

@item Cut
@xref{Cut}.

@item Copy
@xref{Copy}.

@item Paste
@xref{Paste}.

@item Erase
@xref{Erase}.

@item Through
@xref{Through}.

@item Delete Line
@xref{DeleteLine}.

@item Delete EOL
@xref{DeleteEOL}.

@item Mark Vert
@xref{MarkVert}.

@item Paste Vert
@xref{PasteVert}.

@item Open Clip@dots{}
@xref{OpenClip}.

@item Save Clip@dots{}
@xref{SaveClip}.

@end table



@node Search
@subsection Search

The Search menu contains commands related to searching for specific
contents or locations within a document.

@table @samp

@item Find@dots{}
@xref{Find}.

@item Find RegExp@dots{}
@xref{FindRegExp}.

@item Replace@dots{}
@xref{Replace}.

@item Replace Once@dots{}
@xref{ReplaceOnce}.

@item Replace All@dots{}
@xref{ReplaceAll}.

@item Repeat Last
@xref{RepeatLast}.

@item Goto Line@dots{}
@xref{GotoLine}.

@item Goto Col@dots{}
@xref{GotoColumn}.

@item Goto Mark@dots{}
@xref{GotoMark}.

@item Match Bracket
@xref{MatchBracket}.

@item Set Bookmark
@xref{SetBookmark}.

@item Unset Bookmark
@xref{UnsetBookmark}.

@item Goto Bookmark
@xref{GotoBookmark}.

@end table



@node Macros
@subsection Macros

The Macros menu contains commands related to creating and using macros.

@table @samp

@item Record
@xref{Record}.

@item Stop
@xref{Record}.

@item Replace@dots{}
@xref{Replace}.

@item Play Once
@itemx Play Many@dots{}
@xref{Play}.

@item Play Macro@dots{}
@xref{Macro}.

@item Open Macro@dots{}
@xref{OpenMacro}.

@item Save Macro@dots{}
@xref{SaveMacro}.

@end table



@node Extras
@subsection Extras

This menu contains a few special items that don't fit in obvious ways
into other menus.

@table @samp

@item Exec@dots{}
@xref{Exec}.

@item Suspend
@xref{Suspend}.

@item Help@dots{}
@xref{Help}.

@item Refresh
@xref{Refresh}.

@item Undo
@xref{Undo}.

@item Redo
@xref{Redo}.

@item Undel Line
@xref{UndelLine}.

@item Center
@xref{Center}.

@item Shift Right
@itemx Shift Left
@xref{Shift}.

@item Paragraph
@xref{Paragraph}.

@item Adjust View
@itemx Center View
@xref{AdjustView}.

@item ToUpper
@xref{ToUpper}.

@item ToLower
@xref{ToLower}.

@item Capitalize
@xref{Capitalize}.

@end table


@node Navigation
@subsection Navigation

The Navigation menu contains commands related moving around in a
document.

@table @samp

@item Move Left
@xref{MoveLeft}.

@item Move Right
@xref{MoveRight}.

@item Line Up
@xref{LineUp}.

@item Line Down
@xref{LineDown}.

@item Prev Page
@xref{PrevPage}.

@item Next Page
@xref{NextPage}.

@item Page Up
@xref{PageUp}.

@item Page Down
@xref{PageDown}.

@item Start Of File
@xref{MoveSOF}.

@item End Of File
@xref{MoveEOF}.

@item Start Of Line
@xref{MoveSOL}.

@item End Of Line
@xref{MoveEOL}.

@item Top Of Screen
@xref{MoveTOS}.

@item Bottom Of Screen
@xref{MoveBOS}.

@item Incr Up
@xref{MoveIncUp}.

@item Incr Down
@xref{MoveIncDown}.

@item Prev Word
@xref{PrevWord}.

@item Next Word
@xref{NextWord}.

@end table



@node Prefs
@subsection Prefs

The Prefs menu contains commands related to setting, storing, and using
your preferred document flags.

@table @samp

@item Tab Size@dots{}
@xref{TabSize}.

@item Tabs as Spaces
@xref{Tabs}.

@item Insert/Over
@xref{Insert}.

@item Free Form
@xref{FreeForm}.

@item Status Bar
@xref{StatusBar}.

@item Hex Code
@xref{HexCode}.

@item Fast GUI
@xref{FastGUI}.

@item Word Wrap
@xref{WordWrap}.

@item Right Margin
@xref{RightMargin}.

@item Auto Indent
@xref{AutoIndent}.

@item Request Order
@xref{RequestOrder}.

@item Preserve CR
@xref{PreserveCR}.

@item Save CR/LF
@xref{CRLF}.

@item Load Prefs@dots{}
@xref{LoadPrefs}.

@item Save Prefs@dots{}
@xref{SavePrefs}.

@item Load AutoPrefs
@xref{LoadAutoPrefs}.

@item Save AutoPrefs
@xref{SaveAutoPrefs}.

@item Save Def Prefs
@xref{SaveDefPrefs}.

@end table



@node Regular Expressions
@section Regular Expressions
@cindex Regular Expressions

Regular expressions are a powerful way of specifying complex search and
replace operations. @code{ne} supports the full regular expression
syntax on US-ASCII and 8-bit documents, but has to impose a restriction on
character sets when searching in UTF-8 text. @xref{UTF-8 Support}.

@subsection Syntax

The following section is taken (with minor modifications) from the GNU regular
expression library documentation and is Copyright @copyright{} Free Software
Foundation.

A regular expression describes a set of strings.  The simplest case is one
that describes a particular string; for example, the string @samp{foo} when
regarded as a regular expression matches @samp{foo} and nothing else.
Nontrivial regular expressions use certain special constructs so that they
can match more than one string.  For example, the regular expression
@samp{foo|bar} matches either the string @samp{foo} or the string
@samp{bar}; the regular expression @samp{c[ad]*r} matches any of the strings
@samp{cr}, @samp{car}, @samp{cdr}, @samp{caar}, @samp{cadddar} and all other
such strings with any number of @samp{a}'s and @samp{d}'s.

Regular expressions have a syntax in which a few characters are special
constructs and the rest are @dfn{ordinary}.  An ordinary character is a
simple regular expression which matches that character and nothing else. The
special characters are @samp{$}, @samp{^}, @samp{.}, @samp{*}, @samp{+},
@samp{?}, @samp{[}, @samp{]} , @samp{(}, @samp{)} and @samp{\}.  Any other
character appearing in a regular expression is ordinary, unless a @samp{\}
precedes it.@refill

For example, @samp{f} is not a special character, so it is ordinary,
and therefore @samp{f} is a regular expression that matches the string @samp{f}
and no other string.  (It does @emph{not} match the string @samp{ff}.)  Likewise,
@samp{o} is a regular expression that matches only @samp{o}.

Any two regular expressions @var{a} and @var{b} can be concatenated.
The result is a regular expression that matches a string if @var{a}
matches some amount of the beginning of that string and @var{b}
matches the rest of the string.

As a simple example, we can concatenate the regular expressions
@samp{f} and @samp{o} to get the regular expression @samp{fo},
which matches only the string @samp{fo}.  Still trivial.

Note: special characters are treated as ordinary ones if they are in
contexts where their special meanings make no sense.  For example,
@samp{*foo} treats @samp{*} as ordinary since there is no preceding
expression on which the @samp{*} can act. It is poor practice to depend on
this behaviour; better to quote the special character anyway, regardless of
where is appears.

The following are the characters and character sequences that have special
meaning within regular expressions. Any character not mentioned here is not
special; it stands for exactly itself for the purposes of searching and
matching.

@table @samp
@item .
is a special character that matches anything except a newline. Using
concatenation, we can make regular expressions like @samp{a.b}, which matches
any three-character string which begins with @samp{a} and ends with
@samp{b}.

@item *
is not a construct by itself; it is a suffix, which means the preceding
regular expression is to be repeated as many times as possible.  In
@samp{fo*}, the @samp{*} applies to the @samp{o}, so @samp{fo*} matches
@samp{f} followed by any number of @samp{o}'s.

The case of zero @samp{o}'s is allowed: @samp{fo*} does match
@samp{f}.

@samp{*} always applies to the @emph{smallest} possible preceding
expression. Thus, @samp{fo*} has a repeating @samp{o}, not a repeating
@samp{fo}.

@item +
@samp{+} is like @samp{*} except that at least one match for the preceding
pattern is required for @samp{+}.  Thus, @samp{c[ad]+r} does not match
@samp{cr} but does match anything else that @samp{c[ad]*r} would match.

@item ?
@samp{?} is like @samp{*} except that it allows either zero or one match for
the preceding pattern.  Thus, @samp{c[ad]?r} matches @samp{cr} or @samp{car}
or @samp{cdr}, and nothing else.

@item [ @dots{} ]
@samp{[} begins a @dfn{character set}, which is terminated by a @samp{]}.
In the simplest case, the characters between the two form the set.
Thus, @samp{[ad]} matches either @samp{a} or @samp{d},
and @samp{[ad]*} matches any string of @samp{a}'s and @samp{d}'s
(including the empty string), from which it follows that
@samp{c[ad]*r} matches @samp{car}, @i{et cetera}.

Character ranges can also be included in a character set, by writing two
characters with a @samp{-} between them.  Thus, @samp{[a-z]} matches any
lower-case letter.  Ranges may be intermixed freely with individual
characters, as in @samp{[a-z$%.]}, which matches any lower case letter or
@samp{$}, @samp{%} or period.

Note that the usual special characters are not special any more inside a
character set.  A completely different set of special characters exists
inside character sets: @samp{]}, @samp{-} and @samp{^}. As @samp{\} is 
not special inside character sets, you cannot use the shortcuts
@samp{\s} or @samp{\w} there.

To include a @samp{]} in a character set, you must make it
the first character.  For example, @samp{[]a]} matches @samp{]} or @samp{a}.
To include a @samp{-}, you must use it in a context where it cannot possibly
indicate a range: that is, as the first character, or immediately
after a range.

Note that when searching in UTF-8 text, a character set may contain
US-ASCII characters only.

@item [^ @dots{} ]
@samp{[^} begins a @dfn{complement character set}, which matches any
character except the ones specified.  Thus, @samp{[^a-z0-9A-Z]} matches
all characters @emph{except} letters and digits. Also in this case, when
searching in UTF-8 text a complemented character set may contain US-ASCII
characters only. @refill

@samp{^} is not special in a character set unless it is the first character.
The character following the @samp{^} is treated as if it were first (it may
be a @samp{-} or a @samp{]}).

@item ^
is a special character that matches the empty string -- but only if at the
beginning of a line in the text being matched.  Otherwise it fails to match
anything.  Thus, @samp{^foo} matches a @samp{foo} that occurs at the
beginning of a line.

@item $
is similar to @samp{^} but matches only at the end of a line. Thus,
@samp{xx*$} matches a string of one or more @samp{x}'s at the end of a
line.

@item \
has two functions: it quotes the above special characters (including
@samp{\}), and it introduces additional special constructs.@refill

Because @samp{\} quotes special characters, @samp{\$} is a regular
expression that matches only @samp{$}, and @samp{\[} is a regular
expression that matches only @samp{[}, and so on.

For the most part, @samp{\} followed by any character matches only that
character.  However, there are several exceptions: characters which, when
preceded by @samp{\}, are special constructs.  Such characters are always
ordinary when encountered on their own.

@item |
specifies an alternative. Two regular expressions @var{a} and @var{b} with
@samp{|} in between form an expression that matches anything that either
@var{a} or @var{b} will match.

Thus, @samp{foo|bar} matches either @samp{foo} or @samp{bar} but no other
string.

@samp{|} applies to the largest possible surrounding expressions.  Only a
surrounding @samp{( @dots{} )} grouping can limit the grouping power of
@samp{|}.

@item ( @dots{} )
is a grouping construct that serves three purposes:

@enumerate
@item
To enclose a set of @samp{|} alternatives for other operations.
Thus, @samp{(foo|bar)x} matches either @samp{foox} or @samp{barx}.

@item
To enclose a complicated expression for the postfix @samp{*} to operate on.
Thus, @samp{ba(na)*} matches @samp{bananana} @i{et cetera}, with any (zero or
more) number of @samp{na}'s.

@item
To mark a matched substring for future reference.

@end enumerate

This last application is not a consequence of the idea of a parenthetical
grouping; it is a separate feature that happens to be assigned as a second
meaning to the same @samp{( @dots{} )} construct because there is no
conflict in practice between the two meanings.  Here is an explanation of
this feature:

@item \@var{digit}
After the end of a @samp{( @dots{} )} construct, the matcher remembers the
beginning and end of the text matched by that construct.  Then, later on in
the regular expression, you can use @samp{\} followed by @var{digit} to mean
``match the same text matched the @var{digit}'th time by the @samp{(
@dots{} )} construct.''  The @samp{( @dots{} )} constructs are numbered
in order of commencement in the regexp.

The strings matching the first nine @samp{( @dots{} )} constructs appearing
in a regular expression are assigned numbers 1 through 9 in order of their
beginnings.
@samp{\1} through @samp{\9} may be used to refer to the text matched by
the corresponding @samp{( @dots{} )} construct.

For example, @samp{(.+)\1} matches any non empty string that is composed of
two identical halves.  The @samp{(.+)} matches the first half, which may be
anything non empty, but the @samp{\1} that follows must match the same exact
text.

@item \b
matches the empty string, but only if it is at the beginning or
end of a word.  Thus, @samp{\bfoo\b} matches any occurrence of
@samp{foo} as a separate word.  @samp{\bball(s|)\b} matches
@samp{ball} or @samp{balls} as a separate word.

@item \B
matches the empty string, provided it is @emph{not} at the beginning or end
of a word.

@item \<
matches the empty string, but only if it is at the beginning
of a word.

@item \>
matches the empty string, but only if it is at the end of a word.

@item \s
matches any white-space character in US-ASCII. These are @key{tab},
@kbd{@key{Control}-J} (line feed), 
@kbd{@key{Control}-k} (vertical tab), 
@kbd{@key{Control}-L} (form feed), 
@kbd{@key{Control}-M} (carriage return), and space. 

@item \w
matches any word-constituent character. These are US-ASCII letters,
numbers and the underscore, independently of the document encoding.

@item \W
matches any character that is not a word-constituent.
@end table

@subsection Replacing regular expressions

Also the replacement string has some special feature when doing a regular
expression search and replace. Exactly as during the search, @samp{\} followed
by @var{digit} stands for ``the text matched the @var{digit}'th time by the
@samp{( @dots{} )} construct in the search expression''. Moreover, @samp{\0}
represent the whole string matched by the regular expression. Thus, for
instance, the replace string @samp{\0\0} has the effect of doubling any string
matched.

Another example: if you search for @samp{(a+)(b+)}, replacing with
@samp{\2x\1}, you will match any string composed by a series of @samp{a}'s
followed by a series of @samp{b}'s, and you will replace it with the
string obtained by moving the @samp{a} in front of the @samp{b}'s, adding
moreover @samp{x} inbetween. For instance, @samp{aaaab} will be matched and
replaced by @samp{bxaaaa}.

Note that the backslash character can escape itself. Thus, to put a
backslash in the replacement string, you have to use @samp{\\}.



@node Automatic Preferences
@section Automatic Preferences
@cindex Automatic preferences

Automatic preferences let you set up a custom configuration that is
automatically used whenever you open a file with a given extension. For
instance, you may prefer a @sc{tab} size of three when editing C sources, but
eight could be more palatable when writing electronic mail.

The use of autoprefs is definitely straightforward. You simply use the
@samp{Save AutoPrefs} menu item (or the @code{SaveAutoPrefs} command;
@pxref{SaveAutoPrefs}) when the current document has the given extension and
the current configuration suits your tastes. The internal state of a series of
options will be recorded as a macro containing commands that reproduce the
current configuration. The macro is then saved in the @file{~/.ne}
directory (which is created if necessary) with the name given by the
extension, postfixed with @samp{#ap}. Thus, the C sources automatic
preferences file will be named @samp{c#ap}, the one for @TeX{} files @samp{tex#ap},
and so on.

Macros are generated with short or long command names depending on the
status of the verbose macros flag. @xref{VerboseMacros}.

Automatic preferences files are loaded and executed whenever a file with a known
extension is opened. Note that you can manually edit such files, and even
insert commands, but any command that does something other than setting a flag
will be rejected, and an error message will be issued.



@node Emergency Save
@section Emergency Save
@cindex Emergency Save

When @code{ne} is interrupted by an abnormal event (for instance, the
crash of your terminal), it will try to save all unsaved
documents in its current directory. Named documents will have their
names prefixed with a @samp{#}. Unnamed documents will be given names
made up of hexadecimal numbers obtained by some addresses in memory
that will make them unique.



@node UTF-8 Support
@section UTF-8 Support
@cindex UTF-8 Support

@code{ne} can manipulate UTF-8 files and supports
UTF-8 when communicating with the user. At startup, @code{ne} fetches
the system locale description, and checks whether it contains the string
@samp{utf8} or @samp{utf-8}. In this case, it starts communicating with
the user using UTF-8. This behaviour can be modified either using a
suitable command line option (see @pxref{Arguments}), or using
@ref{UTF8IO}. This makes it possible to display and read from the
keyboard a wide range of characters.

Independently of the input/output encoding, @code{ne} keeps track of the
encoding of each document. @code{ne} does not try to select a particular
coding on a document, unless it is forced to do so, for instance because a
certain character is inserted. Once a document has a definite encoding,
however, it keeps it forever.

More precisely, every document may be in one of three @emph{encoding
modes}: US-ASCII, when it is entirely composed of US-ASCII characters;
8-bit, if it contains also other characters, but it is not UTF-8
encoded; and finally, UTF-8, if it is UTF-8-encoded.

The behaviour of @code{ne} in US-ASCII and 8-bit mode is similar to
previous versions: each byte in the document is considered a separate
character.

There are, however, two important differences: first, if I/O is not
UTF-8 encoded, @emph{any} encoding of the ISO-8859 family will work
flawlessly, as @code{ne} merely reads bytes from the keyboard and
displays bytes on the screen. On the contrary, in the case of UTF-8
input/output @code{ne} must take a decision as to which encoding is used
for non-UTF-8 documents, and presently this is hardwired to ISO-8859-1.
Second, 8-bit documents use localized casing and
character type functions. This means that case-insensitive searches or
case foldings will work with, say, Cyrillic characters, provided that
your locale is set correctly.

In UTF-8 mode, instead, @code{ne} interprets the bytes in the document in
a different way---several bytes may encode a single character. The whole
process is completely transparent to the user, but if you really want to
look at the document content, you can switch to 8-bit mode (see
@pxref{UTF8}).

For most operations, UTF-8 support should be transparent. However, in
some cases, in particular when mixing documents with different encodings,
@code{ne} will refuse to perform certain operations because of
incompatible encodings.

The main limitation of UTF-8 documents is that when searching for a
regular expression in a UTF-8 text, character sets may only contain
US-ASCII characters (see @pxref{Regular Expressions}). You can, of
course, partially emulate a full UTF-8 character set implementation
specifying the possible alternatives using @samp{|} (but you have no
ranges).



@node Commands
@chapter Commands
@cindex Commands

Everything @code{ne} can do is specified through a command. Commands can
be manually typed on the command line, bound to a key, to a menu item,
or grouped into macros for easier manipulation. If you want to fully
exploit the power of @code{ne}, you will be faced sooner or later with
using commands directly.

@menu
* General Guidelines::
* File Commands::
* Document Commands::
* Clip Commands::
* Search Commands::
* Macros Commands::
* Undo Commands::
* Formatting Commands::
* Preferences Commands::
* Navigation Commands::
* Editing Commands::
* Support Commands::
@end menu



@node General Guidelines
@section General Guidelines
@cindex Long names
@cindex Short names
@cindex Command arguments
@cindex Flags
@cindex Repeating actions
@cindex Escape conventions
@cindex Quoting conventions

Every command in @code{ne} has a long and a short name. Except in a very
few cases, the short name is given by two or three letters that are the
initials of the words that form the long name. For instance,
@code{SearchBack} has short name @code{SB}, @code{SaveDefPrefs} has the
short name @code{SDP}, and @code{AdjustView}'s short name is @code{AV}.
There are some exceptions however. The most frequently used commands
such as @code{Exit} have one-letter short names (@code{X}). Also some
commands use a different short name to avoid clashes with a more common
command's short name. For example, @code{StatusBar}'s short name is
@code{ST} rather than @code{SB}  to avoid clashes with
@code{SearchBack}'s short name.

A command always has at most one argument. This is a chosen limitation
that allows @code{ne}'s parsing of commands and macros to be very fast.
Moreover, it nullifies nearly all problems related to delimiters, escape
characters, and the like. The unique argument can be a number, a string,
or a flag modifier. You can easily distinguish these three cases even
without this manual by looking at what the @code{Help} command says
about the given command. Note that when a command's argument is enclosed
in square brackets, it is optional.

Strings are general purpose arguments. Numbers are used to modify internal
parameters, such as the size of a @sc{tab}. A flag modifier is an optional
number that is interpreted as follows:

@itemize @bullet{}

@item
0 means clearing the flag;

@item
1 (or any positive number) means setting the flag;

@item
no number means toggling the flag.

@end itemize

Thus, @code{StatusBar 1} will activate that status bar, while @code{I} will
toggle insert/overstrike. This design choice is due to the fact that most of
the time during interactive editing you need to @emph{change} a
flag. For instance, you may be in insert mode and you want to overstrike, or
vice versa. Absolute settings (those with a number) are useful essentially
for macros. It is reasonable to use the fastest approach for the most
frequent interactive event. When a number or a string is required and the
argument is optional, most of the time you will be prompted to
type the argument on the command line.

As for the input line, for numeric arguments you can choose between
decimal, octal and hexadecimal notation in the standard way:
a number starting with @samp{0} is considered in octal, a number
starting with @samp{0x} is considered in hexadecimal, and in all other
cases decimal base is assumed.

When a number represents how many times @code{ne} should repeat an
action, it is always understood that the command will terminate when the
conditions for applying it are no longer true. For instance, the
@code{Paragraph} command accepts the number of paragraphs to format.
But if not enough paragraphs exists in the text, only the available ones
will be formatted.

This easily allows performing operations on an entire document by specifying
preposterously huge numbers as arguments. @code{ToUpper 200000000} will
make all the words in the document upper case. (At least, one would
hope so!) Note that this is much faster than recording a macro with
the command @code{ToUpper} in it and playing it many times because in
the former case the command has to be parsed just one time.

In any case, if a macro or a repeated operation takes too long, you can stop
it using the interrupt key (@kbd{@key{Control}-\}).


To handle situations such as an argument string starting with a
space, @code{ne} implements a simple mechanism whereby you can enclose
any string argument in double quotes. If the first non-blank character
after the command and last character of the command line are double
quotes, the quotes will be removed and whatever is left will be used as
the string argument. For example, the @code{Find} command to find a
space could be entered on the command line or in a macro as
@code{Find " "}. The only case needing special treatment is
when a string starts and ends with double quotes. The command
@code{Find ""quote""} would locate the next occurrence of the string
@samp{"quote"} (including the double quotes). However,
@code{Find onequote"} wouldn't require special treatment because the
command argument doesn't both start and end with a double quote.

@ignore

    N O T E   T O    D O C U M E N T   M A I N T A I N E R S

It is essential that, in the following sections, all cross references
explaining the text of a command point only to another command, unless
they are inside an @ifclear autohelp / @endif pair. This way, the text
can be automagically extracted for the on-line help with makeinfo.

@end ignore



@node File Commands
@section File Commands

These commands allow opening and saving files. They all act in the
context of the current document (i.e., the document displayed when the
command is issued).


@menu
* Open::
* OpenNew::
* Save::
* SaveAs::
* SaveAll::
@end menu



@node Open
@subsection Open
@cmindex Open

@noindent Syntax: @code{Open [@var{filename}]}@*
@noindent Abbreviation: @code{O}

@noindent replaces the contents of the current document with that
of the file specified by the @var{filename} string. (To load @var{filename}'s
content into a new document without changing the current document,
see @ref{OpenNew}.) The current document's macro, search, and replace
strings are preserved.

If the optional @var{filename} argument is not specified, the
file requester is opened, and you are prompted to select a file. (You
can inhibit the file requester opening by using the @code{NoFileReq}
command; see @ref{NoFileReq}.)

If you escape from the file requester, you can input the file name on the
command line, the default being the current document name, if available.

If the current document is marked as modified at the time the command is
issued, you have to confirm the action.




@node OpenNew
@subsection OpenNew
@cmindex OpenNew

@noindent Syntax: @code{OpenNew [@var{filename}]}@*
@noindent Abbreviation: @code{ON}

@noindent creates a new document and loads into it the contents of the
file specified by the optional @var{filename} string. This new document will
inherit the macro, search, and replace strings from the current
document.

If @var{filename} is unspecified, the file requester behaves the same as
for the @code{Open} command; see @ref{Open}.




@node Save
@subsection Save
@cmindex Save

@noindent Syntax: @code{Save}@*
@noindent Abbreviation: @code{S}

@noindent saves the current document using its default file name.

If the current document is unnamed, the file requester will open and you
will be prompted to select a file. (You can inhibit the file requester opening by
using the @code{NoFileReq} command; see @ref{NoFileReq}.)

If you escape from the file requester, you can input the file name on the
command line.

If the file has been modified since the current document was loaded or last
saved (perhaps by another user), @code{ne} will warn you before overwriting
the updated file. If the current document's read only flag is set, @code{ne}
will prompt you before attempting to save it.




@node SaveAs
@subsection SaveAs
@cmindex SaveAs

@noindent Syntax: @code{SaveAs [@var{filename}]}@*
@noindent Abbreviation: @code{SA}

@noindent saves the current document using the specified string as the file name.

If the optional @var{filename} argument is not specified, the
file requester will open and you will be prompted to select a file. (You
can inhibit the file requester opening by using the @code{NoFileReq}
command; see @ref{NoFileReq}.)

If you escape from the file requester, you can enter the file name on the
input line, the default being the current document name, if available.

If the file has been modified since the current document was loaded or last
saved (perhaps by another user), @code{ne} will warn you before overwriting
the updated file. If the current document's read only flag is set, @code{ne}
will prompt you before attempting to save it.


@node SaveAll
@subsection SaveAll
@cmindex SaveAll

@noindent Syntax: @code{SaveAll}@*
@noindent Abbreviation: @code{SL}

@noindent saves all modified documents. If any modified documents cannot be
saved, the action is suspended and an error message is issued. Note that
only named documents can be saved, so @code{SaveAll} will report an error
if you have any modified unnamed documents. Other reasons @code{SaveAll}
may fail include: if any of the modified documents' corresponding files
have been updated since they were loaded or last saved, or if any modified
documents' read only flags are set.



@node Document Commands
@section Document Commands

These commands allow manipulation of the circular list of documents in @code{ne}.

@menu
* Quit::
* Exit::
* NewDoc::
* Clear::
* CloseDoc::
* NextDoc::
* PrevDoc::
* SelectDoc::
@end menu



@node Quit
@subsection Quit
@cmindex Quit

@noindent Syntax: @code{Quit}@*
@noindent Abbreviation: @code{Q}

@noindent closes all documents and exits. If any documents are modified, you
have to confirm the action.




@node Exit
@subsection Exit
@cmindex Exit

@noindent Syntax: @code{Exit}@*
@noindent Abbreviation: @code{X}

@noindent saves all modified documents, closes them and exits. If
any documents cannot be saved, the action is suspended and an error message
is issued and no documents are closed. Note that only named documents can be
saved, so @code{Exit} will report an error if you have any modified unnamed
documents. Like @code{SaveAll}, @code{Exit} will not save a document if its
corresponding file has been modified since the document was loaded or last
saved, or if its read only flag is set, in which cases an error is reported
and no documents are closed.




@node NewDoc
@subsection NewDoc
@cmindex NewDoc

@noindent Syntax: @code{NewDoc}@*
@noindent Abbreviation: @code{N}

@noindent creates a new, empty, unnamed document that becomes the current document.
The position of the document in the document list is just after the current
document. The preferences of the new document are a copy of the
preferences of the current document.



@node Clear
@subsection Clear
@cmindex Clear

@noindent Syntax: @code{Clear}@*
@noindent Abbreviation: @code{CL}

@noindent destroys the contents of the current document and of its undo
buffer. Moreover, the document becomes unnamed. If your current document is
marked as modified, you have to confirm the action.



@node CloseDoc
@subsection CloseDoc
@cmindex CloseDoc

@noindent Syntax: @code{CloseDoc}@*
@noindent Abbreviation: @code{CD}

@noindent closes the current document. The document is removed from
@code{ne}'s list and, if it is the only existing document, @code{ne}
exits. If the document was modified since it was last saved, you have to
confirm the action.



@node NextDoc
@subsection NextDoc
@cmindex NextDoc

@noindent Syntax: @code{NextDoc}@*
@noindent Abbreviation: @code{ND}

@noindent sets as current document the next document in the document list.




@node PrevDoc
@subsection PrevDoc
@cmindex PrevDoc

@noindent Syntax: @code{PrevDoc}@*
@noindent Abbreviation: @code{PD}

@noindent sets as current document the previous document in the document list.



@node SelectDoc
@subsection SelectDoc
@cmindex SelectDoc

@noindent Syntax: @code{SelectDoc}@*
@noindent Abbreviation: @code{SD}

@noindent displays a requester containing the names of all the
documents in memory. Your cursor will be on your current document's
name, and documents with unsaved changes will be indicated with
asterisks (and bold if your terminal supports that). You select
whichever document you want to become the current document by moving
your cursor to its name and hitting @key{Return}..

While the list of documents is displayed, you can close unmodified
documents with your @code{CloseDoc} key (@kbd{@key{Control}-Q}), save
named documents with your @code{Save} key (@kbd{@key{Control}-S}), and
you can alter their relative order using your @code{NextDoc} and
@code{PrevDoc} keys (@key{f2} and @key{f3}), which have the effect of
swapping your currently selected document with the next or previous
document in the list, respectively.

If you escape from the requester, the requester goes away, you are
returned to your original current document (unless you closed it!),
and no reordering of documents takes place.

@code{SelectDoc} is especially useful if you have a large number of
documents open or if you want to quickly see which documents contain
unsaved changes. See @ref{NextDoc}, and @ref{PrevDoc}.




@node Clip Commands
@section Clip Commands

These commands control the clipping system. A @dfn{clip} is a snippet of
text separate from any document, which you can save to a file or insert
into a document. You can select text in a document and copy it to a
clip, optionally deleting it from your text. You can also load text
directly from a file into a clip. @code{ne} can have any number of
clips, which are distinguished by an integer. Most clip commands act on
the current clip, which can be selected with @code{ClipNumber}. Clips can
be copied and pasted in two ways---normally (as lines of text) or
vertically (as a rectangular block of characters).

Note that by using the @code{Through} command you can automatically pass a
(possibly vertical) block of text through any filter (such as @code{sort} under
@sc{un*x}).

@menu
* Mark::
* MarkVert::
* Copy::
* Cut::
* Paste::
* PasteVert::
* Erase::
* Shift::
* OpenClip::
* SaveClip::
* ClipNumber::
* Through::
@end menu



@node Mark
@subsection Mark
@cmindex Mark

@noindent Syntax: @code{Mark [0|1]}@*
@noindent Abbreviation: @code{M}

@noindent sets the mark at the current position or cancels the previous mark.
The mark and cursor together define the range of text over which clips
(@code{Cut}, @code{Copy}, @code{Erase}) and left and right shifts operate.

If you invoke @code{Mark} with no arguments, it will set the mark. If you
specify 0 or 1, the mark will be cancelled or set to the current position,
respectively.  A capital @samp{M} appears on the status bar, if the mark is
active.


@node MarkVert
@subsection MarkVert
@cmindex MarkVert

@noindent Syntax: @code{MarkVert [0|1]}@*
@noindent Abbreviation: @code{MV}

@noindent is the same as @code{Mark}, but the region manipulated by the
cut/paste commands is the rectangle having as vertices the cursor and the mark.
If you invoke @code{MarkVert} with no arguments, it will set the mark. If you
specify 0 or 1, the mark will be cancelled or set to the current position,
respectively. Moreover, a capital @samp{V}, rather than a capital @samp{M},
will appear on the status bar.

For example, if you have the following text:
@example
   aaaBbbccc
   aaabbbccc
   aaabbbCcc
@end example
@noindent and you set a vertical mark at @samp{B} then move the cursor to @samp{C},
you can cut or copy all of the @samp{B}s.

If you have made a vertical cut or copy, it's very likely you will want to
use @code{PasteVert} rather than the usual @code{Paste} to reinsert the text
in a rectangle. See @ref{PasteVert}.


@node Copy
@subsection Copy
@cmindex Copy

@noindent Syntax: @code{Copy [@var{n}]}@*
@noindent Abbreviation: @code{C}

@noindent copies the contents of the characters lying between the cursor
and the mark into the clip specified by the optional numeric argument, the
default clip being the current clip, which can be set with the
@code{ClipNumber} command; see @ref{ClipNumber}. If the current mark was
vertical, the rectangle of characters defined by the cursor and the mark is
copied instead.



@node Cut
@subsection Cut
@cmindex Cut

@noindent Syntax: @code{Cut [@var{n}]}@*
@noindent Abbreviation: @code{CU}

@noindent acts just like @code{Copy}, but also deletes the block being copied.



@node Paste
@subsection Paste
@cmindex Paste

@noindent Syntax: @code{Paste [@var{n}]}@*
@noindent Abbreviation: @code{P}

@noindent pastes the contents of specified clip into the current
document at the cursor position. If you don't specify the clip number,
the current clip is used; Specify which clip is current with @ref{ClipNumber}.



@node PasteVert
@subsection PasteVert
@cmindex PasteVert

@noindent Syntax: @code{PasteVert [@var{n}]}@*
@noindent Abbreviation: @code{PV}

@noindent vertically pastes the contents of the specified clip, the default
being the current clip. Each line of the clip is inserted on consecutive
lines at the horizontal cursor position.



@node Erase
@subsection Erase
@cmindex Erase

@noindent Syntax: @code{Erase}@*
@noindent Abbreviation: @code{E}

@noindent acts like @code{Cut}, but the block is just deleted and not
copied into any clip.



@node Shift
@subsection Shift
@cmindex Shift

@noindent Syntax: @code{Shift [<|>][n][t|s]}@*
@noindent Abbreviation: @code{SH}

@noindent shifts the text on lines between the mark and the cursor either
right (@samp{>}) or left (@samp{<}) by adding or removing
white space on each line. The adjustment size, specified as an unsigned
integer @samp{n}, is in units of the current tab size (@samp{t}) or spaces
(@samp{s}). The defaults are @samp{>}, @samp{1}, and @samp{t}. Adjustments
start at the left edge of a vertical mark, or column 1 otherwise. If the mark
is not currently set, only the current line is affected.

@code{Shift} will insert tab characters only if @samp{s} is not used, and both
of the document's @code{Tabs} and @code{ShiftTabs} flags are set---in which
case an upper case @samp{T} will appear in the status bar. If either of the
@code{Tabs} or @code{ShiftTabs} flags is unset (i.e there is no upper case
@samp{T} in the status bar) @code{Shift} will only insert spaces.

In the case of left shifts, if any indicated line has insufficient leading
white space for the requested adjustment to be made, then @code{Shift}
reports an error and makes no changes.



@node OpenClip
@subsection OpenClip
@cmindex OpenClip

@noindent Syntax: @code{OpenClip [@var{filename}]}@*
@noindent Abbreviation: @code{OC}

@noindent loads the given file name as the current clip, just as if you
cut or copied it from the current document; see @ref{Copy}.

If the optional @var{filename} argument is not specified, the
file requester will open and you will be prompted to select a file. (You
can inhibit the file requester opening by using the @code{NoFileReq}
command; see @ref{NoFileReq}.)

If you escape from the file requester, you can enter the file name on the
input line.



@node SaveClip
@subsection SaveClip
@cmindex SaveClip

@noindent Syntax: @code{SaveClip [@var{filename}]}@*
@noindent Abbreviation: @code{SC}

@noindent saves the current clip to the given file name.

If the optional @var{filename} argument is not specified, the
file requester will open and you will be prompted to select a file. (You
can inhibit the file requester opening by using the @code{NoFileReq}
command; see @ref{NoFileReq}.)

If you escape from the file requester, you can enter the file name on the
input line.



@node ClipNumber
@subsection ClipNumber
@cmindex ClipNumber

@noindent Syntax: @code{ClipNumber [@var{n}]}@*
@noindent Abbreviation: @code{CN}

@noindent sets the current clip number. This number is used by
@code{OpenClip} and @code{SaveClip}, and by @code{Copy}, @code{Cut} and
@code{Paste} if they are called without any argument. Its default value is
zero. @var{n} is limited only by the integer size of the machine @code{ne}
is running on.

If the optional argument @var{n} is not specified, you can enter it on the
input line, the default being the current clip number.



@node Through
@subsection Through
@cmindex Through

@noindent Syntax: @code{Through [@var{command}]}@*
@noindent Abbreviation: @code{T}

@noindent asks the shell to execute @var{command}, piping the current block in
the standard input, and replacing it with the output of the command. This
command is most useful with filters, such as @code{sort}. Its practical effect
is to pass the block through the specified filter.

Note that by selecting an empty block (or equivalently by having the mark
unset) you can use @code{Through} to insert the output of any @sc{un*x}
command in your file.

If the optional argument @var{command} is not specified, you can enter it on
the input line.



@node Search Commands
@section Search Commands

These commands control the search system. @code{ne} offers two complementary
searching techniques: a simple, fast exact matching search (optionally
ignoring case), and a very flexible and powerful, but slower, regular
expression search based on the GNU @code{regex} library (again,
optionally case insensitive).

@menu
* Find::
* FindRegExp::
* Replace::
* ReplaceOnce::
* ReplaceAll::
* RepeatLast::
* MatchBracket::
* AutoMatchBracket::
* SearchBack::
* CaseSearch::
* AutoComplete::
@end menu



@node Find
@subsection Find
@cmindex Find

@noindent Syntax: @code{Find [@var{pattern}]}@*
@noindent Abbreviation: @code{F}

@noindent searches for the given pattern. The cursor is positioned on the
first occurrence of the pattern, or an error message is given. The direction
and the case sensitivity of the search are established by the value of the
back search and case sensitive search flags. See @ref{SearchBack}, and
@ref{CaseSearch}.

If the optional argument @var{pattern} is not specified, you can enter it on
the input line, the default being the last pattern used.



@node FindRegExp
@subsection FindRegExp
@cmindex FindRegExp

@noindent Syntax: @code{FindRegExp [@var{pattern}]}@*
@noindent Abbreviation: @code{FX}

@noindent searches the current document for the given extended regular expression
@ifclear autohelp
(@pxref{Regular Expressions})
@end ifclear
. The cursor is positioned on the first string
matching the expression. The direction and the kind of search are established
by the value of the back search and case sensitive search flags. See
@ref{SearchBack}, and @ref{CaseSearch}.

If the optional argument @var{pattern} is not specified, you can enter it on
the input line, the default being the last pattern used.



@node Replace
@subsection Replace
@cmindex Replace

@noindent Syntax: @code{Replace [@var{string}]}@*
@noindent Abbreviation: @code{R}

@noindent moves to the first match of the most recent find string or regular
expression and prompts you for which action to perform. You can choose among:

@itemize @bullet

@item
replacing the string found with the given string and moving to the next match
(@samp{Yes});

@item
moving to the next match (@samp{No});

@item
replacing the string found with the given string, and stopping the search (@samp{Last});

@item
stopping the search immediately (@samp{Quit});

@item
replacing @emph{all} occurrences of the find string with the given string
(@samp{All});

@item
reversing the search direction (@samp{Backward} or @samp{Forward});
this choice will also modify the value of the back search flag.
See @ref{SearchBack}.

@end itemize

@code{Replace} is mainly useful for interactive editing. @code{ReplaceOnce},
@code{ReplaceAll} and @code{RepeatLast} are more suited to macros.

If no find string was ever specified, you can enter it on the input line.
If the optional argument @var{string} is not specified, you can enter it on
the input line, the default being the last string used. When the last search
was a regular expression search, there are some special
features you can use in the replace string
@ifclear autohelp
(@pxref{Regular Expressions})
@end ifclear
. See @ref{FindRegExp}.

Note that normally a search starts just one character after the cursor.
However, when @code{Replace} is invoked, the search starts at the character
just @emph{under} the cursor, so that you can safely @code{Find} a pattern
and @code{Replace} it without having to move back.

@noindent @strong{Warning:} when recording a macro with @ref{Record}, there
is no trace in the macro of your interaction with @code{ne} during the
replacement process. When the macro is played, you will again have to choose
which actions to perform. If you want to apply automatic replacement of
strings for a certain number of times, you should look at @ref{ReplaceOnce},
@ref{ReplaceAll}, and @ref{RepeatLast}.



@node ReplaceOnce
@subsection ReplaceOnce
@cmindex ReplaceOnce

@noindent Syntax: @code{ReplaceOnce [@var{string}]}@*
@noindent Abbreviation: @code{R1}

@noindent acts just like @code{Replace}, but without any interaction with you
(unless there is no find string). The first string matched by the last search
pattern, if it exists, is replaced by the given replacement string.

If the optional argument @var{string} is not specified, you can enter it on
the input line, the default being the last string used.



@node ReplaceAll
@subsection ReplaceAll
@cmindex ReplaceAll

@noindent Syntax: @code{ReplaceAll [@var{string}]}@*
@noindent Abbreviation: @code{RA}

@noindent is similar to @code{ReplaceOnce}, but replaces @emph{all}
occurrences of the last search pattern between the cursor position and the
end of the document (in the direction indicated by the @code{SearchBack} flag)
with the given replacement string.

If the optional argument @var{string} is not specified, you can enter it on
the input line, the default being the last string used.

Note that a single @code{Undo} will restore @emph{all} the occurrences of the search
pattern replaced by @code{ReplaceAll}. See @ref{Undo}.



@node RepeatLast
@subsection RepeatLast
@cmindex RepeatLast

@noindent Syntax: @code{RepeatLast [@var{times}] [F|Find|R|Replace]}@*
@noindent Abbreviation: @code{RL}

@noindent repeats for the given number of times the last find or replace operation
(with replace we mean here a single replace, even if the last @code{Replace}
operation ended with a global substitution). If you don't specify either
@var{Find} or @var{Replace}, it will repeat whichever one was last performed.

If any find or replace operation runs into the end of the document (in the direction
indicated by the @code{SearchBack} flag) and stops, then and only then will a
@code{RepeatLast} command ``wrap around'' to the other end of the document to
continue the find or replace operation.

@code{RepeatLast} is especially useful for researching a given number of times, or
replacing something a given number of times. The standard technique for
accomplishing this is:

@enumerate

@item
@code{Find} (or @code{FindRegExp}) the string you are interested in;

@item
if you want to repeat a replace operation, @code{ReplaceOnce} with
the replacement string you are interested in;

@item
now issue a @code{RepeatLast @var{n}-1} command, where @var{n} is the
number of occurrences you wanted to skip over, or replace.

@end enumerate

The important thing about this sequence of actions is that it will
work this way even in a macro. The @code{Replace} command cannot be used
in a macro unless you really want to interact with @code{ne} during the
macro execution. Avoiding interaction during macros is the primary
reason the commands @code{ReplaceAll} and @code{ReplaceOnce} are
provided.



@node MatchBracket
@subsection MatchBracket
@cmindex MatchBracket

@noindent Syntax: @code{MatchBracket}@*
@noindent Abbreviation: @code{MB}

@noindent moves the cursor to the bracket associated with the bracket the
cursor is on. If the cursor is not on a bracket, or there is no bracket
associated with the current one, an error message is issued. Recognized
brackets are @samp{@{@}}, @samp{()}, @samp{[]} @samp{<>}, and @samp{`'}.
See @ref{AutoMatchBracket}.

@node AutoMatchBracket
@subsection AutoMatchBracket
@cmindex AutoMatchBracket

@noindent Syntax: @code{AutoMatchBracket [0..15]}@*
@noindent Abbreviation: @code{AMB}

@noindent sets the auto match bracket mode. When the cursor is on a
recognized bracket (@samp{@{@}}, @samp{()}, @samp{[]}, @samp{<>}, or @samp{`'}) and
the associated matching bracket is on the screen, that matching bracket
will be indicated according to the mode. The mode is either zero for no
bracket matching, or the sum of 1 (altered foreground and background
brightness), 2 (inverse), 4 (bold), and 8 (underline). If no mode is specified,
@code{ne} prompts you for one. The default mode is 1. See @ref{MatchBracket}.



@node SearchBack
@subsection SearchBack
@cmindex SearchBack

@noindent Syntax: @code{SearchBack [0|1]}@*
@noindent Abbreviation: @code{SB}

@noindent sets the back search flag. When this flag is true, every search or
replacement command is performed backwards.

If you invoke @code{SearchBack} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{b} will appear on the status bar if the flag is true.

Note that this flag also can be set through interactions with the
@code{Replace} command. See @ref{Replace}.



@node CaseSearch
@subsection CaseSearch
@cmindex CaseSearch

@noindent Syntax: @code{CaseSearch [0|1]}@*
@noindent Abbreviation: @code{CS}

@noindent sets the case sensitivity flag. When this flag is true, the
search commands distinguish between the upper and lower case letters. By
default the flag is false.

If you invoke @code{CaseSearch} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{c} will appear on the status bar if the flag is true.




@node AutoComplete
@subsection AutoComplete
@cmindex AutoComplete

@noindent Syntax: @code{AutoComplete [@var{prefix}]}@*
@noindent Abbreviation: @code{AC}

@noindent attempts to extend the @var{prefix} using matching words from your
open documents, and inserts the extended text into your document. If the
@var{prefix} can be extended unambiguously, the matching text is immediately
inserted into your document. Otherwise, @code{ne} displays a
selection of all words in open documents that match @var{prefix}, and inserts
the word you select into the current document.
Matching words from the current document display normally; those which only
exist in other open documents are bold and with a trailing asterisk. If no
@var{prefix} is given on the command line, or if @code{AutoComplete} is
selected from the @code{Extras} menu or using a keyboard shortcut, the word
characters to the immediate left of the cursor in the current document are used
as the @var{prefix}. Note that if no word characters are to the left of the
cursor, or the @var{prefix} given on the command line is an empty string
(@code{""}), then all words in all your open documents are displayed. Prefix
matches may be case sensitive or not depending on the current document's
@code{CaseSearch} flag state. See @ref{CaseSearch}.



@node Macros Commands
@section Macros Commands

Macros are lists of commands. Any series of operations that has to be
performed frequently is a good candidate for being a macro.

Macros can be written manually: they are just ASCII files, each command
occupying a line (lines starting with @samp{#} are considered comments;
lines starting with other nonalphabetical characters are presently
ignored). But the real power of macros is that they be recorded during
the normal usage of @code{ne}. When the recording terminates, the
operations that have been recorded can be saved for later use. Note that
each document has its own current macro (the last macro that has been opened
or recorded).


@menu
* Record::
* Play::
* Macro::
* OpenMacro::
* SaveMacro::
* UnloadMacros::
@end menu


@node Record
@subsection Record
@cmindex Record

@noindent Syntax: @code{Record [0|1]}@*
@noindent Abbreviation: @code{REC}

@noindent starts, stops, cancels, or resumes macro recording. With no
arguments, @code{Record} starts recording your commands as a new macro
unless recording is already underway. In that case, macro recording is
stopped, and the newly recorded macro replaces the current document's
unnamed macro. The new macro can be played or saved via @ref{Play},
or @ref{SaveMacro}. The default key binding for @kbd{@key{Control}-T}
is @code{Record} with no arguments, and is by far the most common way
to use the @code{Record} command.

If you've started recording a macro and wish to cancel rather than wipe
out your existing macro, you can cancel the recording by using @code{Record 0}.
An error will be displayed if you aren't recording already, but it's harmless.

Sometimes you've got a macro either recorded or loaded from a file
(see @ref{OpenMacro}), but you'd like to record additional commands onto
the end of it. @code{Record 1} will do that. It will start recording onto
the end of a copy of your current document's macro. An error will be displayed
if you are already recording, but it's otherwise harmless.



@node Play
@subsection Play
@cmindex Play

@noindent Syntax: @code{Play [@var{times}]}@*
@noindent Abbreviation: @code{PL}

@noindent plays the current document's macro the given number of times. If the
optional argument @var{times} is not specified, you can enter it on the
input line.

A (possibly iterated) macro execution terminates as soon as its stream of
instructions is exhausted, or one of its commands returns an error. This means
that, for instance, you can perform some complex operation on all the lines
containing a certain pattern by recording a macro that searches for the pattern
and performs the operation, and then playing it a preposterously huge number of
times.

Execution of a macro can be interrupted by @kbd{@key{Control}-\}.



@node Macro
@subsection Macro
@cmindex Macro

@noindent Syntax: @code{Macro [@var{filename}]}@*
@noindent Abbreviation: @code{MA}

@noindent executes the given file name as a macro.

If the optional @var{filename} argument is not specified, the file
requester is opened, and you are prompted to select a file. (You can
inhibit the file requester opening by using the @code{NoFileReq}
command; see @ref{NoFileReq}.)

If you escape from the file requester, you can input the file name on the
command line.

Note that macros whose names do not conflict with a command can be called
without using @code{Macro}. Whenever @code{ne} is required to perform a command
it cannot find in its internal tables, it will look for a macro by that
name in the current directory. If this search also fails, @code{ne} looks in
@file{~/.ne} and finally in the @file{macros} subdirectory of @code{ne}'s
global directory (defined when @code{ne} was built, or in a place specified by
your @code{NE_GLOBAL_DIR} environment variable) for a macro file by that name.

@noindent @strong{Warning:} the first time a macro is executed it is cached
into a hash table and is kept @emph{forever} in memory unless the
@code{UnloadMacros} command is issued; see @ref{UnloadMacros}. The next time a
macro with the same file name is invoked, the cached list is searched for it
before accessing the file using a case insensitive string comparison. That is,
if you call @code{~/foobar/macro}, a subsequent call for @code{/usr/MACRO} or
even just @code{MaCrO} will use the cached version of @code{~/foobar/macro}.
Note that the cache table is global to @code{ne} and not specific to any single
document. This greatly improves efficiency when macros are used repeatedly.



@node OpenMacro
@subsection OpenMacro
@cmindex OpenMacro

@noindent Syntax: @code{OpenMacro [@var{filename}]}@*
@noindent Abbreviation: @code{OM}

@noindent loads the given file name as the current document's macro just as if you
@code{Record}ed it; see @ref{Record}.

If the optional @var{filename} argument is not specified, the
file requester is opened, and you are prompted to select a file. (You
can inhibit the file requester opening by using the @code{NoFileReq}
command; see @ref{NoFileReq}.)

If you escape from the file requester, you can input the file name on the
command line.



@node SaveMacro
@subsection SaveMacro
@cmindex SaveMacro

@noindent Syntax: @code{SaveMacro [@var{filename}]}@*
@noindent Abbreviation: @code{SM}

@noindent saves the current document's macro in a file with the given name.

If the optional @var{filename} argument is not specified, the
file requester is opened, and you are prompted to select a file. (You
can inhibit the file requester opening by using the @code{NoFileReq}
command; see @ref{NoFileReq}.)

If you escape from the file requester, you can input the file name on the
command line.

@code{SaveMacro} is of course most useful for saving macros you just
recorded. The macros can then be loaded as normal text files for
further editing, if necessary. Note that @code{SaveMacro} converts
@code{InsertChar} commands into a possibly smaller number of
@code{InsertString} commands. This makes macros easier to
read and edit. See @ref{InsertChar}, and @ref{InsertString}.




@node UnloadMacros
@subsection UnloadMacros
@cmindex UnloadMacros

@noindent Syntax: @code{UnloadMacros}@*
@noindent Abbreviation: @code{UM}

@noindent frees the macro cache list. After this command, the @code{Macro}
command will be forced to search for the file containing the macros it has to
play.

@code{UnloadMacros} is especially useful if you are experimenting with a macro
bound to some keystroke, and you are interactively modifying it and playing it.
@code{UnloadMacros} forces @code{ne} to look for the newer version available.




@node Undo Commands
@section Undo Commands

The following commands control the undo system.

@menu
* Undo::
* Redo::
* UndelLine::
* DoUndo::
* AtomicUndo::
@end menu



@node Undo
@subsection Undo
@cmindex Undo

@noindent Syntax: @code{Undo [@var{n}]}@*
@noindent Abbreviation: @code{U}

@noindent undoes the last @var{n} actions. If @var{n} is not specified, it is
assumed to be one. After you undo a number of actions, you can @code{Redo}
all or some of them; see @ref{Redo}. However, if you take any new
actions after having @code{Undo}ne some, you can no longer @code{Redo}
those @code{Undo}ne actions. See @ref{Redo}.



@node Redo
@subsection Redo
@cmindex Redo

@noindent Syntax: @code{Redo [@var{n}]}@*
@noindent Abbreviation: @code{RE}

@noindent redoes the last @var{n} actions undone by @code{Undo} (as long
as you don't take any actions that change the text between the
@code{Undo} and @code{Redo} commands). If @var{n} is not specified, it
is assumed to be one. You can only @code{Redo} actions that have been
@code{Undo}ne. See @ref{Undo}.



@node UndelLine
@subsection UndelLine
@cmindex UndelLine

@noindent Syntax: @code{UndelLine [@var{n}]}@*
@noindent Abbreviation: @code{UL}

@noindent inserts at the cursor position for @var{n} times the last non-empty line
that was deleted with the @code{DeleteLine} command. If @var{n} is not
specified, it is assumed to be one.

@code{UndelLine} is most useful in that it allows a very fast way of moving
one line around. Just delete it, and undelete it somewhere else. It is
also an easy way to replicate a line without getting involved with clips.

Note that @code{UndelLine} works independently of the status of the
undo flag. See @ref{DoUndo}.



@node DoUndo
@subsection DoUndo
@cmindex DoUndo

@noindent Syntax: @code{DoUndo [0|1]}@*
@noindent Abbreviation: @code{DU}

@noindent sets the flag that enables or disables the undo system. When you turn
the undo system off, all the recorded actions are discarded, and the undo
buffers are reset.

If you invoke @code{DoUndo} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{u} will appear on the status bar if the flag is true. (The
@samp{U} will be upper case if the flag is true and the @code{AtomicUndo}
level is non-zero.)

The usefulness of this option relies in the fact that the undo system is a major
memory eater. If you plan to do massive editing (say, cutting and pasting
megabytes of text) it is a good idea to disable the undo system, both for
improving (doubling) performance and for using less (half) memory. Except for
this, on a virtual memory system we see no reason to not keep the undo flag
always true, and this is indeed the default.


@node AtomicUndo
@subsection AtomicUndo
@cmindex AtomicUndo

@noindent Syntax: @code{AtomicUndo [0|+|-]}@*
@noindent Abbreviation: @code{AU}

@noindent increases, decreases, sets or clears the @code{AtomicUndo} level.
The normal level is zero. All current document changes made while the
@code{AtomicUndo} level is above zero are treated as a single change by the
@code{Undo} and @code{Redo} commands. If no parameter is given, a level of 0
is set to 1; otherwise the current non-zero level is decremented. If 0 is
given, the level is reset to zero. Parameters of @samp{+} and @samp{-} respectively
increment and decrement the level, which in no case can be negative. If the
level is above zero, the @code{DoUndo} flag in the status bar, which is
normally a lower-case @samp{u}, becomes upper case @samp{U}.

Two other actions will reset the @code{AtomicUndo} level to zero: invoking the
@code{Undo} command, and disabling the undo system with the @code{DoUndo}
command. You cannot set a non-zero @code{AtomicUndo} level unless the undo
system is enabled.

Note: macros that you wish to undo and redo atomically---i.e., as if they
were single commands---should begin with @code{AtomicUndo +} and end with
@code{AtomicUndo -} so that they can call and/or be called by other macros.




@node Formatting Commands
@section Formatting Commands

The following commands allow simple formatting operations on the text. Note
that for @code{ne} a paragraph is delimited by an empty line or a line with
leading white space incongruous with that of preceeding lines.

@menu
* Center::
* Paragraph::
* ToUpper::
* ToLower::
* Capitalize::
* RightMargin::
* WordWrap::
* AutoIndent::
@end menu



@node Center
@subsection Center
@cmindex Center

@noindent Syntax: @code{Center [@var{n}]}@*
@noindent Abbreviation: @code{CE}

@noindent centers @var{n} lines from the cursor position onwards. If @var{n}
is not specified, it is assumed to be one. The lines are centered with
spaces, relatively to the value of the right margin as set by the
@code{RightMargin} command. See @ref{RightMargin}.



@node Paragraph
@subsection Paragraph
@cmindex Paragraph

@noindent Syntax: @code{Paragraph [@var{n}]}@*
@noindent Abbreviation: @code{PA}

@noindent reformats @var{n} paragraphs from the cursor position onwards. If
@var{n} is not specified, it is assumed to be one. The paragraphs are
formatted relatively to the value of the right margin as set by the
@code{RightMargin} command. See @ref{RightMargin}.

@code{ne}'s notion of a paragraph includes the current non-blank line
(regardless of its leading white space) and all subsequent non-blank lines
that have identical (to each other's---not to the first line's) leading
white space. Therefore your paragraphs can have various first line
indentations and left margins.

@ignore

Note: the following was true, briefly, but was removed because it
sometimes broke "normal" text that contained certain characters.
I'm leaving this here in case someday we reimplement this feature.

@code{Paragraph} also takes into account
characters commonly used at the left edge of block comments (@samp{/},
@samp{*}, @samp{#}, spaces, and tabs) or quoted email (@samp{>}), and
attempts to preserve those on the left edge when possible.

@end ignore

After the @code{Paragraph} command completes, your cursor will be
positioned on the first non-blank character after the last reformatted
paragraph (or, if there is no such character, at the end of the document).

@code{Paragraph} does not insert ``smart'' spaces after full stops and colons,
nor does it do other ``smart'' things such as justification. If you need such
facilities, you should consider using a text formatter. @TeX{} for example is
usually an excellent choice.



@node ToUpper
@subsection ToUpper
@cmindex ToUpper

@noindent Syntax: @code{ToUpper [@var{n}]}@*
@noindent Abbreviation: @code{TU}

@noindent shifts to upper case the letters from the cursor position up to the
end of a word, and moves to the first letter of next word for @var{n} times.

The description of the command may seem a little bit cryptic. What is really
happening is that there are situations where you only want to upper case the
last part of a word. In this case, you just have to position the cursor in
the first character you want to upper case, and use @code{ToUpper} with no
argument.

If you apply @code{ToUpper} on the first character of a word, it will
just upper case @var{n} words.



@node ToLower
@subsection ToLower
@cmindex ToLower

@noindent Syntax: @code{ToLower [@var{n}]}@*
@noindent Abbreviation: @code{TL}

@noindent acts exactly like @code{ToUpper}, but lowers the case. See @ref{ToUpper}.



@node Capitalize
@subsection Capitalize
@cmindex Capitalize

@noindent Syntax: @code{Capitalize [@var{n}]}@*
@noindent Abbreviation: @code{CA}

@noindent acts exactly like @code{ToUpper}, but capitalizes, that is, makes the first
letter upper case and the other ones lower case. See @ref{ToUpper}.



@node RightMargin
@subsection RightMargin
@cmindex RightMargin

@noindent Syntax: @code{RightMargin [@var{n}]}@*
@noindent Abbreviation: @code{RM}

@noindent sets the right margin for all formatting operations, and for @code{WordWrap}.
See @ref{WordWrap}.

If the optional argument @var{n} is not specified, you can enter it on the
input line, the default being the current value of the right margin.

A value of zero for @var{n} will force @code{ne} to use (what it thinks it is)
the current screen width as right margin.




@node WordWrap
@subsection WordWrap
@cmindex WordWrap

@noindent Syntax: @code{WordWrap [0|1]}@*
@noindent Abbreviation: @code{WW}

@noindent sets the word wrap flag. When this flag is true, @code{ne} will
automatically break lines of text when you attempt to insert characters beyond
the right margin. See @ref{RightMargin}.

@ignore

See ignored section in "paragraph" discussion.
@code{ne} will attempt to preserve
certain invariant characters at the left edge of paragraphs typically used to
indicate comments in source code or quoted passages in email text. See @ref{Paragraph}.

@end ignore

If you invoke @code{WordWrap} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{w} will appear on the status bar if the flag is true.




@node AutoIndent
@subsection AutoIndent
@cmindex AutoIndent

@noindent Syntax: @code{AutoIndent [0|1]}@*
@noindent Abbreviation: @code{AI}

@noindent sets the auto indent flag. When this flag is true, @code{ne} will
automatically insert @sc{tab}s and spaces on a new line (created by an
@code{InsertLine} command, or by automatic word wrapping) in such a way to
replicate the initial spaces of the previous line. Most useful for indenting
programs.

If you invoke @code{AutoIndent} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{a} will appear on the status bar if the flag is true.

@code{AutoIndent} features a nice interaction with @code{Undo}. Whenever a
new line is created, the insertion of spaces is recorded as a separate
action in the undo buffer (with respect to the line creation). If you are
not satisfied with the indentation, just give the @code{Undo} command and
the indentation will disappear (but the new line will remain in place, since
its creation has been recorded as a separate action). See @ref{Undo}.




@node Preferences Commands
@section Preferences Commands

These commands allow you to set your preferences, that is, the value of
a series of flags that modify the behaviour of @code{ne}. (Some of the
flag commands, like the command for the indent flag, appear in other
sections.) The status of the flags can be saved and restored later
either by writing them out to a file (saved as a macro that suitably
sets the flags) or by pushing them onto a ``preferences stack''. The
back search and the read only flags are not saved, because they do not
represent a preference, but rather a temporary state. The escape time
and the turbo parameter are global to @code{ne}, and are not
saved. However, you can add manually to a preferences file any
preferences command (such as @code{EscapeTime} or @code{Turbo});
usually, this will be done to the default preferences file
@file{~/.ne/.default#ap}.

Note that there is an automatic preferences system, which automagically loads a
preferences file related to the extension of the file name. Automatic
preferences files are kept in your @file{~/.ne} directory. They
are named as an extension postfixed with @samp{#ap}. Each time you open
a file whose name has an extension for which there is an automatic
preferences file, the latter is executed. Opening a file which has no
extension causes the prefs from @file{~/.ne/.default#ap} to be loaded.
If you want to inhibit this process, you can clear the automatic
preferences flag. See @ref{AutoPrefs}.


@menu
* Flags::
* AutoPrefs::
* Binary::
* Insert::
* FastGUI::
* FreeForm::
* NoFileReq::
* RequestOrder::
* StatusBar::
* HexCode::
* ReadOnly::
* EscapeTime::
* TabSize::
* Tabs::
* DelTabs::
* ShiftTabs::
* Turbo::
* VerboseMacros::
* PreserveCR::
* CRLF::
* VisualBell::
* PushPrefs::
* PopPrefs::
* LoadPrefs::
* SavePrefs::
* LoadAutoPrefs::
* SaveAutoPrefs::
* SaveDefPrefs::
* Modified::
* Syntax::
* UTF8::
* UTF8Auto::
* UTF8IO::
@end menu



@node Flags
@subsection Flags
@cmindex Flags

@noindent Syntax: @code{Flags}@*
@noindent Abbreviation: @code{FLAG}

@noindent displays a list of all the status flags for ne and their
associated commands. It is not recorded when recording a macro.

@example
FLAG COMMAND      ABBR  DESCRIPTION
  i   Insert        I    inserts new characters (vs. replacing)
  a   AutoIndent    AI   aligns cursor under previous line after <Return>
  b   SearchBack    SB   searches search backward rather than forward
  c   CaseSearch    CS   searches are case sensitive
  w   WordWrap      WW   breaks long lines as you type
  f   FreeForm      FF   allows cursor to move beyond the end of lines
  p   AutoPrefs     AP   use automatic preferences based on file extension
  v   VerboseMacros VM   record macros using use long command names
  u   DoUndo        DU   record edits for later undoing
  r   ReadOnly      RO   changes are not allowed/saves are prompted
  t/T Tabs          TAB  TAB key inserts TABs instead of spaces
  T   ShiftTabs     SHT  Shift may insert TABs (only if 't' is also set)
  d   DelTabs       DT   BS and DEL may remove tabs worth of space
  B/! Binary        B    affects file loading/saving
  M   Mark          M    mark set for line-oriented block operations
  V   MarkVert      MV   like mark, but block is rectangle
  R   Record        REC  actions are being recorded in a macro
  P   PreserveCR    PCR  affects how <CR> chars are loaded from files
  C   CRLF          CRLF use CR/LF as line terminator
  @@   UTF8IO        U8IO I/O (keyboard and terminal) are UTF-8 encoded
A/8/U UTF8          U8   the document encoding (ASCII, 8-bit or UTF-8)
  */_ Modified      MOD  document has been modified since last saved
  _   (none)             file's modtime changed since doc was loaded/saved
@end example

The @code{RequestOrder} and @code{AutoMatchBracket} flags' states are not indicated on the status bar.
See @ref{RequestOrder} and @ref{AutoMatchBracket} respectively.
A @samp{!} indicates the last line is not terminated.

@node AutoPrefs
@subsection AutoPrefs
@cmindex AutoPrefs

@noindent Syntax: @code{AutoPrefs [0|1]}@*
@noindent Abbreviation: @code{AP}

@noindent sets the automatic preferences flag. If this flag is true, each
time an @code{Open} command is executed and a file is loaded, @code{ne} will
look for an automatic preferences file in your @file{~/.ne} directory.
The preferences file name is given by the extension of the file loaded,
postfixed with @samp{#ap}. Thus, for instance, C sources have an associated
@file{c#ap} file.
@ifclear autohelp
@xref{Automatic Preferences}.
@end ifclear

If you invoke @code{AutoPrefs} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{p} will appear on the status bar if the flag is true.



@node Binary
@subsection Binary
@cmindex Binary
@cindex Binary files

@noindent Syntax: @code{Binary [0|1]}@*
@noindent Abbreviation: @code{B}

@noindent sets the binary flag. When this flag is true, loading and saving a
document is performed in a different way. On loading, only nulls are
considered newlines; on saving, nulls are saved instead of newlines. This
allows you to edit a binary file, fix some text in it, and save it without
modifying anything else. Normally, line feeds, carriage returns and nulls are
considered newlines, so that what you load will have all nulls and carriage
returns substituted by newlines when saved.

Note that since usually binary files contain a great number of nulls, and every
null will be considered a line terminator, the memory necessary for loading a
binary file can be several times bigger than the length of the file
itself. Thus, binary editing within @code{ne} should be considered not a
normal activity, but rather an exceptional one.

If you invoke @code{Binary} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. An upper
case @samp{B} will appear on the status bar if the flag is true. If false,
a @samp{-} or @samp{!} will indicate whether the last line of the document is
empty, which will determine whether the resulting file will have a normal line
termination when the document is saved.



@node Insert
@subsection Insert
@cmindex Insert

@noindent Syntax: @code{Insert [0|1]}@*
@noindent Abbreviation: @code{I}

@noindent sets the insert flag. If this flag is true, the text you type is
inserted, otherwise it overwrites the existing characters. This also
governs the behaviour of the @code{InsertChar} and @code{InsertString}
commands.

If you invoke @code{Insert} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{i} will appear on the status bar if the flag is true.



@node FastGUI
@subsection FastGUI
@cmindex FastGUI

@noindent Syntax: @code{FastGUI [0|1]}@*
@noindent Abbreviation: @code{FG}

@noindent sets the fast graphical user interface flag. When this flag is
true, @code{ne} tries to print as little as possible while displaying
menus and the status bar. In particular, menu items are highlighted by
the cursor only, the status bar is not highlighted (which allows
printing it with fewer characters), the current position of the mark is not
highlighted, and the hexadecimal code for the character under the cursor is not
displayed. This option is only (but very) useful if you are using @code{ne}
through a slow connection.

If you invoke @code{FastGUI} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively.

The @code{FastGUI} setting is saved in your @file{~/.ne/.default#ap} file
when you use the @code{SaveDefPrefs} command or the @samp{Save Def Prefs} menu.
It is not saved by the @code{SaveAutoPrefs} command.



@node FreeForm
@subsection FreeForm
@cmindex FreeForm

@noindent Syntax: @code{FreeForm [0|1]}@*
@noindent Abbreviation: @code{FF}

@noindent sets the free form flag. When this flag is true, you can move with
the cursor anywhere on the screen, even where there is no text present (however,
you cannot move inside the space expansion of a @sc{tab} character).

If you invoke @code{FreeForm} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{f} will appear on the status bar if the flag is true.

The issue free-form-versus-non-free-form is a major religious war that
has engaged users from day one. The due of the implementor is to allow
both choices, and to set as default the correct one (in his humble
opinion). In this case, non-free-form.



@node NoFileReq
@subsection NoFileReq
@cmindex NoFileReq

@noindent Syntax: @code{NoFileReq [0|1]}@*
@noindent Abbreviation: @code{NFR}

@noindent sets the file requester flag. When this flag is true,
the file requester is never opened, under any circumstances.

If you invoke @code{NoFileReq} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively.



@node RequestOrder
@subsection RequestOrder
@cmindex RequestOrder

@noindent Syntax: @code{RequestOrder [0|1]}@*
@noindent Abbreviation: @code{RQO}

@noindent sets the request order flag. When this flag is true,
the requester displays entries in column order. Otherwise entries
are displayed by rows.

If you invoke @code{RequestOrder} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively.

The @code{RequestOrder} setting is saved in your @file{~/.ne/.default#ap} file
when you use the @code{SaveDefPrefs} command or the @samp{Save Def Prefs} menu.
It is not saved by the @code{SaveAutoPrefs} command.



@node StatusBar
@subsection StatusBar
@cmindex StatusBar

@noindent Syntax: @code{StatusBar [0|1]}@*
@noindent Abbreviation: @code{ST}

@noindent sets the status bar flag. When this flag is true, the status bar is
displayed at the bottom of the screen. There are only two reasons to
turn off the status bar we are aware of:

@itemize @bullet{}

@item
if you are using @code{ne} through a slow connection, updating the
line/column indicator can really slow down editing;

@item
scrolling caused by cursor movement on terminals that do not allow to set a
scrolling region can produce annoying flashes at the bottom of the screen.

@end itemize

If you invoke @code{StatusBar} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively.

The @code{StatusBar} setting is saved in your @file{~/.ne/.default#ap} file
when you use the @code{SaveDefPrefs} command or the @samp{Save Def Prefs} menu.
It is not saved by the @code{SaveAutoPrefs} command.




@node HexCode
@subsection HexCode
@cmindex HexCode

@noindent Syntax: @code{HexCode [0|1]}@*
@noindent Abbreviation: @code{HC}

@noindent sets the hex code flag. When this flag is true, the
hexadecimal code of the character currently under the cursor is
displayed on the status bar.




@node ReadOnly
@subsection ReadOnly
@cmindex ReadOnly

@noindent Syntax: @code{ReadOnly [0|1]}@*
@noindent Abbreviation: @code{RO}

@noindent sets the read only flag. When this flag is true, no editing can be
performed on the document (any such attempt produces an error message). Saving
read only documents is inhibited as well; you must affirmatively answer a prompt
to save a document with the read only flag set. This
flag is automatically set whenever you open a file that you cannot write to.
See @ref{Open}.

If you invoke @code{ReadOnly} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{r} will appear on the status bar if the flag is true.



@node EscapeTime
@subsection EscapeTime
@cmindex EscapeTime

@noindent Syntax: @code{EscapeTime [@var{n}]}@*
@noindent Abbreviation: @code{ET}

@noindent sets the escape time. The @key{Escape} key is recognized as such
after @var{n} tenths of second.
@ifclear autohelp
(@pxref{Motivations and Design}.)
@end ifclear
Along slow connections, it can happen that the default value of 10 is
too low: in this case, escape sequences (e.g., those of the arrow keys)
could be erroneously broken into an escape and some spurious characters.
Rising the escape time usually solves this problem. Allowed values range
from 0 to 255. Note that you can accelerate the recognition of the @key{Escape}
key by hitting it twice in a row.

Note that the escape time is global to @code{ne}, and it is not saved. However,
you can add an @code{EscapeTime} command manually to a preferences file.



@node TabSize
@subsection TabSize
@cmindex TabSize

@noindent Syntax: @code{TabSize [@var{size}]}@*
@noindent Abbreviation: @code{TS}

@noindent sets the number of spaces @code{ne} will use when expanding a
@sc{tab} character.

If the optional argument @var{size} is not specified, you can enter it on the
input line, the default being the current @sc{tab} size. Allowed values are
strictly between 0 and half the width of the screen.



@node Tabs
@subsection Tabs
@cmindex Tabs

@noindent Syntax: @code{Tabs [0|1]}@*
@noindent Abbreviation: @code{TAB}

@noindent sets the @code{Tabs} flag. When this flag is set, @key{Tab} key and
the @code{InsertTab} command will insert literal @var{TAB} characters.
Otherwise it will insert enough spaces to have the same visual effect.

In normal editing, the @key{Tab} key invokes the command
"@code{InsertTab} 1". Unlike most others, the @key{Tab} key cannot
be mapped to other commands. Thus the @code{Tabs} flag provides the
only customization @code{ne} offers for the @key{Tab} key.

If set, either a lower case @samp{t} or upper case @samp{T} will appear
in the status bar depending on the state of the @code{ShiftTabs} flag.
(The @code{ShiftTabs} flag is irrelevant if the @code{Tabs} flag is off.)
See @ref{ShiftTabs}.



@node DelTabs
@subsection DelTabs
@cmindex DelTabs

@noindent Syntax: @code{DelTabs [0|1]}@*
@noindent Abbreviation: @code{DT}

@noindent sets the @code{DelTabs} flag. When this flag is set, a @samp{d}
will appear on the status bar, and the @key{BackSpace} and @key{Del} keys will
remove a tab's worth of @var{space} characters if a @var{TAB} character could
have occupied the same whitespace in the current line as the removed spaces.
This is the deletion counterpart to the @code{Tabs} flag. See @ref{Tabs}.



@node ShiftTabs
@subsection ShiftTabs
@cmindex ShiftTabs

@noindent Syntax: @code{ShiftTabs [0|1]}@*
@noindent Abbreviation: @code{SHT}

@noindent sets the @code{ShiftTabs} flag. @code{ShiftTabs} has an effect only
when the @code{Tabs} flag is set, in which case an upper case @samp{T}
appears in the status bar. When this flag and the @code{Tabs} flag are
both set, left and right @code{Shift} commands may use tab characters to
adjust leading white space. Otherwise only spaces are used. See @ref{Shift}.



@node Turbo
@subsection Turbo
@cmindex Turbo

@noindent Syntax: @code{Turbo [@var{steps}]}@*
@noindent Abbreviation: @code{TUR}

@noindent sets the turbo parameter. Iterated actions and
global replaces will update at most @var{steps} lines of the screen (or
at most twice the number of visible rows if @var{steps} is zero); then,
update will be delayed to the end of the action.

This feature is most useful when massive operations (such as replacing
thousands of occurrences of a pattern) have to be performed. After having
updated @var{steps} lines, @code{ne} can proceed at maximum speed, because
no visual update has to be performed.

The value of the turbo parameter has to be adapted to the kind of
terminal you are using. Very high values can be good on high-speed
terminals, since the time required for the visual updates is very small,
and it is always safer to look at what the editor is really doing. On
slow terminals, however, small values ensure that operations such as
paragraph formatting will not take too long.

You have to be careful about setting the turbo parameter too low. @code{ne}
keeps track internally of the part of the screen that needs refresh in a
very rough way. This means that a value of less than, say, 8 will force it
to do a lot of unnecessary refresh.

The default value of this parameter is zero, which means twice the number
of lines of the screen; for several reasons this does seem to be a good
value.



@node VerboseMacros
@subsection VerboseMacros
@cmindex VerboseMacros

@noindent Syntax: @code{VerboseMacros [0|1]}@*
@noindent Abbreviation: @code{VM}

@noindent sets the verbose macros flag. When this flag is true, all macros
generated by recording or by automatic preferences saving will contain
full names, instead of short names. This is highly desirable if you are
going to edit the macro manually, but it can slow down command parsing.

If you invoke @code{VerboseMacros} with no arguments, it will toggle the flag. If you
specify 0 or 1, the flag will be set to false or true, respectively. A lower
case @samp{v} will appear on the status bar if the flag is true.

The only reason to use this flag is when recording a macro that will be
played a great number of times. Automatic preferences files are too short to
be an issue with respect to execution timing.

The @code{VerboseMacros} setting is saved in your @file{~/.ne/.default#ap} file
when you use the @code{SaveDefPrefs} command or the @samp{Save Def Prefs} menu.
It is not saved by the @code{SaveAutoPrefs} command.


@node PreserveCR
@subsection PreserveCR
@cmindex PreserveCR

@noindent Syntax: @code{PreserveCR [0|1]}@*
@noindent Abbreviation: @code{PCR}

@noindent sets the preserve carriage returns flag.  When a file is
loaded into a document for which this flag is false, both CR (carriage
return) and NL (new line) characters are treated as line terminators.
If the flag is true, CR characters do not act as line terminators but
are instead preserved in the document. This flag has no effect except
when loading a file into a document.

If you invoke @code{PreserveCR} with no arguments, it will toggle the flag.
If you specify 0 or 1, the flag will be set to false or true,
respectively. An upper case @samp{P} will appear on the status bar if the
flag is true.



@node CRLF
@subsection CRLF
@cmindex CRLF

@noindent Syntax: @code{CRLF [0|1]}@*
@noindent Abbreviation: @code{CRLF}

@noindent sets the CR/LF flag. When a file is
saved from a document for which this flag is true, both a CR (carriage
return) and a NL (new line) character are output as line terminators.
This flag has no effect except when saving a file.

This flag is automatically set if you load a file that has at least one
CR/LF sequence in it.

If you invoke @code{CRLF} with no arguments, it will toggle the flag.
If you specify 0 or 1, the flag will be set to false or true,
respectively. An upper case @samp{C} will appear on the status bar if the
flag is true.



@node VisualBell
@subsection VisualBell
@cmindex VisualBell

@noindent Syntax: @code{VisualBell [0|1]}@*
@noindent Abbreviation: @code{VB}

@noindent sets the visual bell flag. When this flag is true, the terminal will
flash (if possible) instead of beeping.

If you invoke @code{VisualBell} with no arguments, it will toggle the flag. If
you specify 0 or 1, the flag will be set to false or true, respectively.



@node PushPrefs
@subsection PushPrefs
@cmindex PushPrefs

@noindent Syntax: @code{PushPrefs [@var{n}]}@*
@noindent Abbreviation: @code{PUSHP}

@noindent pushes @var{n} copies of the user preferences onto a stack. If
not specified, @var{n} defaults to one. Use the @code{PopPrefs} command
to pop preferences off the stack and restore the values. See @ref{PopPrefs}. Note that the
preferences stack is global, not document-specific, so you could
@code{PushPrefs} one document's preferences, switch documents, then
@code{PopPrefs} those preferences, thereby altering the preferences for
the second document. The maximum preferences stack depth is 32.

@code{PushPrefs} and @code{PopPrefs} are useful in macros that require
certain preferences to work properly.  A macro can @code{PushPrefs},
change any preferences necessary, do its work, then @code{PopPrefs} to
restore the users previous preferences settings.

@noindent @code{PushPrefs} saves the following values on the preferences stack:

@example
  AutoIndent  DelTabs   NoFileReq    StatusBar  VisualBell
  AutoPrefs   DoUndo    PreserveCR   ShiftTabs  WordWrap
  Binary      FreeForm  ReadOnly     Tabs
  CaseSearch  HexCode   RightMargin  TabSize
  ClipNumber  Insert    SearchBack   UTF8Auto
@end example



@node PopPrefs
@subsection PopPrefs
@cmindex PopPrefs

@noindent Syntax: @code{PopPrefs [@var{n}]}@*
@noindent Abbreviation: @code{POPP}

@noindent pops @var{n} sets of preferences from the preferences stack (where they were
placed previously by @code{PushPrefs}) and applies those preferences to the
current document. See @ref{PushPrefs}. If not specified, @var{n} defaults to one. Note that the
preferences stack is global, not document specific. Therefore you could
@code{PushPrefs} one document's preferences, switch documents, then @code{PopPrefs}
those settings altering the preferences for the second document. The
maximum preferences stack depth is 32.

@code{PushPrefs} and @code{PopPrefs} are useful in macros that require
certain preferences to work properly.  A macro can @code{PushPrefs},
change any preferences necessary, do its work, then @code{PopPrefs} to
restore the users previous preferences settings.

@noindent PopPrefs restores the following values from the preferences stack:

@example
  AutoIndent  DelTabs   NoFileReq    StatusBar  VisualBell
  AutoPrefs   DoUndo    PreserveCR   ShiftTabs  WordWrap
  Binary      FreeForm  ReadOnly     Tabs
  CaseSearch  HexCode   RightMargin  TabSize
  ClipNumber  Insert    SearchBack   UTF8Auto
@end example



@node LoadPrefs
@subsection LoadPrefs
@cmindex LoadPrefs

@noindent Syntax: @code{LoadPrefs [@var{filename}]}@*
@noindent Abbreviation: @code{LP}

@noindent loads the given preference file, and sets the current preferences
accordingly.

If the optional @var{filename} argument is not specified, the file
requester is opened, and you are prompted to select a file. (You can
inhibit the file requester opening by using the @code{NoFileReq}
command; see @ref{NoFileReq}.) If you escape from the file requester, you
can input the file name on the command line.

Note that a preferences file is just a macro containing only option
modifiers. You can manually edit a preferences file for special
purposes, such as filtering out specific settings.
@ifclear autohelp
@xref{Hints and Tricks}.
@end ifclear



@node SavePrefs
@subsection SavePrefs
@cmindex SavePrefs

@noindent Syntax: @code{SavePrefs [@var{filename}]}@*
@noindent Abbreviation: @code{SP}

@noindent saves the current preferences to the given file.

If the optional @var{filename} argument is not specified, the file
requester is opened, and you are prompted to select a file. (You can
inhibit the file requester opening by using the @code{NoFileReq}
command; see @ref{NoFileReq}.) If you escape from the file requester, you
can input the file name on the command line.



@node LoadAutoPrefs
@subsection LoadAutoPrefs
@cmindex LoadAutoPrefs

@noindent Syntax: @code{LoadAutoPrefs}@*
@noindent Abbreviation: @code{LAP}

@noindent loads the preferences file in @file{~/.ne} associated
with the current document's file name extension. If the current file
name has no extension, the default preferences are loaded.
See @ref{AutoPrefs}.



@node SaveAutoPrefs
@subsection SaveAutoPrefs
@cmindex SaveAutoPrefs

@noindent Syntax: @code{SaveAutoPrefs}@*
@noindent Abbreviation: @code{SAP}

@noindent saves the current preferences to the file in @file{~/.ne}
associated with the current document's file name extension. If the
current file name has no extension, an error message is issued.
See @ref{AutoPrefs}.



@node SaveDefPrefs
@subsection SaveDefPrefs
@cmindex SaveDefPrefs

@noindent Syntax: @code{SaveDefPrefs}@*
@noindent Abbreviation: @code{SDP}

@noindent saves the current preferences to the @file{~/.ne/.default#ap} file.
This file is always loaded by @code{ne} at startup.



@node Modified
@subsection Modified
@cmindex Modified

@noindent Syntax: @code{Modified [0|1]}@*
@noindent Abbreviation: @code{MOD}

@noindent sets the modified flag.  This flag is set automatically
whenever a document is modified, and is used to determine which documents
need to be saved by @code{SaveAll} or when @code{ne} exits.  Normally you would not alter
this flag, but when a document is inadvertently modified and you don't
want the changes saved, @code{Modified} provides a way to make
@code{ne} consider the document unchanged.

If you invoke @code{Modified} with no arguments, it will toggle the flag.
If you specify 0 or 1, the flag will be set to false or true,
respectively. An asterisk (@samp{*}) will appear on the status bar when
this flag is set. If your terminal supports underlining, it will be underlined
if the corresponding file's modification time has changed since the document
was loaded or saved (perhaps by another user).



@node Syntax
@subsection Syntax
@cmindex Syntax

@noindent Syntax: @code{Syntax [@var{name}|*]}@*
@noindent Abbreviation: @code{SY}

@noindent loads the syntax with the given name, and colors the
current document accordingly.

If the optional @var{name} argument is not specified, you are
prompted for one. The current one, if set, is suggested as the
default. Use the @key{Tab} key for a requester of the extant
syntax recognizers. The special @var{name} * turns off syntax highlighting for
the current document. Otherwise, @var{name} must match a syntax
definition either in your @file{~/.ne/syntax} directory or in a
directory named @samp{syntax} inside @code{ne}'s global directory.
Additionally, @code{ne} has a table mapping common suffixes to
syntax names. If there is no syntax with a given name, @code{ne}
will try to remap the name using the following table  (the string
before the colon is the name of the syntax file):

@ignore

    N O T E   T O    D O C U M E N T   M A I N T A I N E R S

The following "example" section is read by info2src.pl to build ne's
extension map. You can break a line if you end it with a "," but
otherwise stick to the .jsf file base name followed by ":" followed by
a list of common extensions. Don't get fancy with this format.

@end ignore

@example
   ada: adb, ads
   asm: s
   c: c++, cc, cpp, cxx, h, h++, hpp, l, lex, y, yacc
   cobol: cbl, cob
   csh: tcsh
   diff: patch
   fortran: f, F, for, f90, F90
   html: htm
   java: js
   lisp: el, lsp
   mason: mas
   ocaml: ml, mli
   pascal: p, pas
   perl: pl, pm
   ps: eps
   puppet: pp
   python: py, sage
   rexx: rex
   ruby: rb
   sh: bash, bash_login, bash_logout, bash_profile, bashrc, ksh,
       profile, rc
   skill: il
   tex: latex, dtx, sty
   texinfo: texi, txi
   troff: 1
   verilog: v, vh, vhd
   xml: xsd
   yaml: yml
@end example



@node UTF8
@subsection UTF8
@cmindex UTF8

@noindent Syntax: @code{UTF8 [0|1]}@*
@noindent Abbreviation: @code{U8}

@noindent sets the UTF-8 flag.  When this flag is
true, @code{ne} considers the current document as UTF-8 coded.  Note that
this flag is set automatically upon file loading (if possible) if you
required automatic detection. See @ref{UTF8Auto}.

If you invoke @code{UTF8} with no arguments, it will toggle the flag.
If you specify 0 or 1, the flag will be set to false or true,
respectively. When you try to set this flag, the document will be checked
for UTF-8 compliance, and you will get an error message in case of
failure. When you try to reset it, the document is set to ASCII or
8-bit, depending on its content.  A @samp{U} will appear on the
status bar if the flag is true. Alternatively, an @samp{A} or an
@samp{8} will be displayed to denote whether the document is composed
exclusively by US-ASCII characters, or also by other 8-bit characters
(whose encoding is likely to be part of the ISO-8859 family). Note that
each time this command modifies the document encoding, it also resets the
undo buffer.



@node UTF8Auto
@subsection UTF8Auto
@cmindex UTF8Auto

@noindent Syntax: @code{UTF8Auto [0|1]}@*
@noindent Abbreviation: @code{U8A}

@noindent sets the UTF-8 automatic-detection flag.  When this flag is
true, @code{ne} will try to guess whether a file just loaded is UTF-8
encoded. Moreover, when a non US-ASCII character is inserted in a pure
US-ASCII document, ne will automatically switch to UTF-8. See @ref{UTF8}. The
flag is true by default if @code{ne} detects UTF-8 I/O at
startup. See @ref{UTF8IO}.

If you invoke @code{UTF8Auto} with no arguments, it will toggle the flag.
If you specify 0 or 1, the flag will be set to false or true,
respectively.



@node UTF8IO
@subsection UTF8IO
@cmindex UTF8IO

@noindent Syntax: @code{UTF8IO [0|1]}@*
@noindent Abbreviation: @code{U8IO}

@noindent sets the UTF-8 input/output flag.  This flag is set automatically
depending on your locale setting, and is used to determine whether
communication with the user (keyboard and terminal) should be UTF-8
encoded. Normally you would not alter this flag, but sometimes @code{ne}
may make the wrong guess (e.g., when you are remotely connected).

If you invoke @code{UTF8IO} with no arguments, it will toggle the flag.
If you specify 0 or 1, the flag will be set to false or true,
respectively. An @samp{@@} will appear on the status bar if the flag is
true.



@node Navigation Commands
@section Navigation Commands

These commands allow you to move through a document. Besides the standard
commands that allow you to move by lines, pages, @i{et cetera}, @code{ne}
has bookmarks that let you mark a position in a file so to move
to the same position later.

@menu
* MoveLeft::
* MoveRight::
* LineUp::
* LineDown::
* GotoLine::
* GotoColumn::
* GotoMark::
* PrevPage::
* NextPage::
* PageUp::
* PageDown::
* PrevWord::
* NextWord::
* MoveEOL::
* MoveSOL::
* MoveTOS::
* MoveBOS::
* MoveEOF::
* MoveSOF::
* MoveEOW::
* MoveIncUp::
* MoveIncDown::
* AdjustView::
* ToggleSEOF::
* ToggleSEOL::
* SetBookmark::
* GotoBookmark::
* UnsetBookmark::
@end menu



@node MoveLeft
@subsection MoveLeft
@cmindex MoveLeft

@noindent Syntax: @code{MoveLeft [@var{n}]}@*
@noindent Abbreviation: @code{ML}

@noindent moves the cursor to the left by one character @var{n} times. If
the optional @var{n} argument is not specified, it is assumed to be one.



@node MoveRight
@subsection MoveRight
@cmindex MoveRight

@noindent Syntax: @code{MoveRight [@var{n}]}@*
@noindent Abbreviation: @code{MR}

@noindent moves the cursor to the right by one character @var{n} times. If
the optional @var{n} argument is not specified, it is assumed to be one.



@node LineUp
@subsection LineUp
@cmindex LineUp

@noindent Syntax: @code{LineUp [@var{n}]}@*
@noindent Abbreviation: @code{LU}

@noindent moves the cursor up by one line @var{n} times. If the optional
@var{n} argument is not specified, it is assumed to be one.



@node LineDown
@subsection LineDown
@cmindex LineDown

@noindent Syntax: @code{LineDown [@var{n}]}@*
@noindent Abbreviation: @code{LD}

@noindent moves the cursor down by one line @var{n} times. If the optional
@var{n} argument is not specified, it is assumed to be one.



@node GotoLine
@subsection GotoLine
@cmindex GotoLine

@noindent Syntax: @code{GotoLine [@var{line}]}@*
@noindent Abbreviation: @code{GL}

@noindent moves the cursor to the @var{line}th line of the file. If @var{line}
is zero or greater than the number of lines in the file, the cursor is
moved to the last line.

If the optional argument @var{line} is not specified, you can enter it on
the input line; the default input response is the current line number.



@node GotoColumn
@subsection GotoColumn
@cmindex GotoColumn

@noindent Syntax: @code{GotoColumn [@var{column}]}@*
@noindent Abbreviation: @code{GC}

@noindent moves the cursor to the @var{column}th column of the file.

If the optional argument @var{line} is not specified, you can enter it on
the input line; the default input response is the current column number.



@node GotoMark
@subsection GotoMark
@cmindex GotoMark

@noindent Syntax: @code{GotoMark}@*
@noindent Abbreviation: @code{GM}

@noindent moves the cursor to the current mark, if it exists. See @ref{Mark}.

@code{GotoMark} is mainly useful if you forgot where you started marking.
If you want to record positions in a file and jump to them later, you
may want to use bookmarks instead. See @ref{SetBookmark}.



@node PrevPage
@subsection PrevPage
@cmindex PrevPage

@noindent Syntax: @code{PrevPage [@var{n}]}@*
@noindent Abbreviation: @code{PP}

@noindent moves the cursor @var{n} pages backward, if the cursor is on the
first line of the screen; otherwise moves the cursor to the first line of
the screen, and moves by @var{n}-1 pages. If the optional @var{n} argument
is not specified, it is assumed to be one.




@node NextPage
@subsection NextPage
@cmindex NextPage

@noindent Syntax: @code{NextPage [@var{n}]}@*
@noindent Abbreviation: @code{NP}

@noindent moves the cursor @var{n} pages forward, if the cursor is on the
last line of the screen; otherwise moves the cursor to the last line of the
screen, and moves by @var{n}-1 pages. If the optional @var{n} argument is
not specified, it is assumed to be one.




@node PageUp
@subsection PageUp
@cmindex PageUp

@noindent Syntax: @code{PageUp [@var{n}]}@*
@noindent Abbreviation: @code{PUP}

@noindent pages the screen backward by @var{n} screens.
If @var{n} is not specified, it is assumed to be one.





@node PageDown
@subsection PageDown
@cmindex PageDown

@noindent Syntax: @code{PageDown [@var{n}]}@*
@noindent Abbreviation: @code{PDN}

@noindent pages the screen forward by @var{n} screens.  If @var{n} is not specified, it is
assumed to be one.




@node PrevWord
@subsection PrevWord
@cmindex PrevWord

@noindent Syntax: @code{PrevWord [@var{n}][<|>]}@*
@noindent Abbreviation: @code{PW}

@noindent moves the cursor to the left to the @var{n}th word beginning or ending.
If the optional @var{n} argument is not specified, one is used.
The optional @samp{<} or @samp{>} determines whether to move to
the word beginning or ending, respectively. If unspecified, the
left end (@samp{<}) is used.



@node NextWord
@subsection NextWord
@cmindex NextWord

@noindent Syntax: @code{NextWord [@var{n}][<|>]}@*
@noindent Abbreviation: @code{NW}

@noindent moves the cursor to the right to the @var{n}th word beginning or ending.
If the optional @var{n} argument is not specified, one is used.
The optional @samp{<} or @samp{>} determines whether to move to
the word beginning or ending, respectively. If unspecified, the
left end (@samp{<}) is used.



@node MoveEOL
@subsection MoveEOL
@cmindex MoveEOL

@noindent Syntax: @code{MoveEOL}@*
@noindent Abbreviation: @code{EOL}

@noindent moves the cursor to the end of the current line  (@code{EOL} = end of
line).




@node MoveSOL
@subsection MoveSOL
@cmindex MoveSOL

@noindent Syntax: @code{MoveSOL}@*
@noindent Abbreviation: @code{SOL}

@noindent moves the cursor to the start of the current line (@code{SOL} = start of
line).




@node MoveTOS
@subsection MoveTOS
@cmindex MoveTOS

@noindent Syntax: @code{MoveTOS}@*
@noindent Abbreviation: @code{TOS}

@noindent moves the cursor to the top line of the screen (@code{TOS} = top of
screen).




@node MoveBOS
@subsection MoveBOS
@cmindex MoveBOS

@noindent Syntax: @code{MoveBOS}@*
@noindent Abbreviation: @code{BOS}

@noindent moves the cursor to the lowest line currently visible (@code{BOS} = bottom of
screen).




@node MoveEOF
@subsection MoveEOF
@cmindex MoveEOF

@noindent Syntax: @code{MoveEOF}@*
@noindent Abbreviation: @code{EOF}

@noindent moves the cursor to the end of the document (@code{EOF} = end of
file).




@node MoveSOF
@subsection MoveSOF
@cmindex MoveSOF

@noindent Syntax: @code{MoveSOF}@*
@noindent Abbreviation: @code{SOF}

@noindent moves the cursor to the start of the document (@code{SOF} = start
of file).




@node MoveEOW
@subsection MoveEOW
@cmindex MoveEOW

@noindent Syntax: @code{MoveEOW [<|>]}@*
@noindent Abbreviation: @code{EOW}

@noindent moves the cursor to the end of the current word, that end being
the right end unless you include the optional parameter @samp{<}. If the
cursor is not currently in a word, or if it's already at the indicated
end, it retains its current location.

@code{MoveEOW} is extremely useful in macros, because it allows you to copy
precisely the word the cursor is on.
@ifclear autohelp
@xref{Hints and Tricks}.
@end ifclear




@node MoveIncUp
@subsection MoveIncUp
@cmindex MoveIncUp

@noindent Syntax: @code{MoveIncUp}@*
@noindent Abbreviation: @code{MIU}

@noindent moves the cursor incrementally towards the beginning of the
document. More precisely, if the cursor is not on the start of the line
it lies on, then it is moved to the start of that line. Otherwise, if it
is on the first line of the screen, then it is moved to the start of the
document; otherwise, it is moved to the first line of the screen.




@node MoveIncDown
@subsection MoveIncDown
@cmindex MoveIncDown

@noindent Syntax: @code{MoveIncDown}@*
@noindent Abbreviation: @code{MID}

@noindent moves the cursor incrementally towards the end of the
document.  More precisely, if the cursor is not on the end of the line
it lies on, then it is moved to the end of that line. Otherwise, if it is
on the last line of the screen, then it is moved to the end of the
document; otherwise, it is moved to the last line of the screen.




@node AdjustView
@subsection AdjustView
@cmindex AdjustView

@noindent Syntax: @code{AdjustView [T|M|B|L|C|R] [@var{n}]}@*
@noindent Abbreviation: @code{AV}

@noindent shifts the view (text visible in the terminal window)
horizontally or vertically without changing the cursor's position in
the document. View adjustments are constrained by the current @sc{tab}
size and the length and width of the current document. If called with
no arguments @samp{T} is assumed.

@samp{T}, @samp{M}, and @samp{B} cause vertical shifts so that the
current line becomes the top, middle, or bottom-most visible line
respectively.

@samp{L}, @samp{C}, and @samp{R} cause horizontal shifts, making the
current column the left-most, center, or right-most visible positions.

A optional number @var{n} immediately after @samp{T}, @samp{B},
@samp{L}, or @samp{R} indicate the number or rows or columns to shift
the view toward the top, bottom, left, or right of the window.

Horizontal and vertical adjustment specifications may be combined,
so that for example @samp{AdjustView TL} shifts the view so
that the current position becomes the top left-most character on
screen (within the limits of the current @sc{tab} size). Likewise,
@samp{AdjustView B3R5} shifts the view three lines toward the bottom and
five columns (excepting @sc{tab} size) toward the right.




@node ToggleSEOF
@subsection ToggleSEOF
@cmindex ToggleSEOF

@noindent Syntax: @code{ToggleSEOF}@*
@noindent Abbreviation: @code{TSEOF}

@noindent moves the cursor to the start of document, if it is not already
there; otherwise, moves it to the end of the document.

This kind of toggling command is very useful in
order to gain some keystrokes on systems with very few keys. See also
@ref{ToggleSEOL}, @ref{MoveSOF}, and @ref{MoveEOF}.



@node ToggleSEOL
@subsection ToggleSEOL
@cmindex ToggleSEOL

@noindent Syntax: @code{ToggleSEOL}@*
@noindent Abbreviation: @code{TSEOL}

@noindent moves the cursor to the start of the current line, if it is not
already there; otherwise, moves it to the end of the current line.

This kind of toggling command is very useful in
order to gain some keystrokes on systems with very few keys. See also
@ref{ToggleSEOF}, @ref{MoveSOL}, and @ref{MoveEOL}.




@node SetBookmark
@subsection SetBookmark
@cmindex SetBookmark

@noindent Syntax: @code{SetBookmark [@var{n}|@var{+1}|@var{-1}|@var{-}|@var{?}]}@*
@noindent Abbreviation: @code{SBM}

@noindent sets a document bookmark to the current cursor position.
Each document has 10 available bookmarks designated @samp{0} to @samp{9},
plus the automatic bookmark designated by @samp{-}. If no option is given,
@samp{0} is assumed. Values of @var{n} from @samp{0} to @samp{9} set the
@var{n}th bookmark, while @samp{+1} and @samp{-1} indicate respectively
the next and previous available unset bookmarks. You can also set the
@samp{-} automatic bookmark, but it will be reset automatically to the
current position whenever a @code{GotoBookmark} command is issued.

The @samp{?} option will cause @code{SetBookmark} to prompt you
for a bookmark designation. The promp will include an indication of which
bookmarks are currently set. You may find this useful in macros, or to bind
a key to @samp{SetBookmark ?}.


@node GotoBookmark
@subsection GotoBookmark
@cmindex GotoBookmark

@noindent Syntax: @code{GotoBookmark [@var{n}|@var{+1}|@var{-1}|@var{-}]}@*
@noindent Abbreviation: @code{GBM}

@noindent moves the cursor to the designated bookmark if that bookmark is
set; see @ref{SetBookmark}. Each document has 10 available bookmarks
designated @samp{0} to @samp{9}, plus the automatic bookmark designated by
@samp{-}. If no option is given, @samp{0} is assumed. The options @samp{+1}
and @samp{-1} indicate respectively the next and previous set bookmarks,
so that repeated @code{GotoBookmark +1} commands will cycle through all
currently set bookmarks. When successful, the @samp{-} automatic bookmark
is set to the position in the document from which the command was issued,
so that @code{GotoBookmark -} returns you to the location from which you
last issued a successful @code{GotoBookmark} command. Subsequent repeated
@code{GotoBookmark -} commands will toggle you between the two locations.

The @samp{?} option will cause @code{GotoBookmark} to prompt you
for a bookmark designation. The promp will include an indication of which
bookmarks are currently set. You may find this useful in macros, or to bind
a key to @samp{GotoBookmark ?}.


@node UnsetBookmark
@subsection UnsetBookmark
@cmindex UnsetBookmark

@noindent Syntax: @code{UnsetBookmark [@var{n}|@var{+1}|@var{-1}|@var{-}|@var{*}]}@*
@noindent Abbreviation: @code{UBM}

@noindent unsets either the @var{n}th bookmark, the next (@var{+1}) or
previous (@var{-1}) set bookmarks, the automatic (@var{-}) bookmark, or
all (@var{*}) bookmarks, making it as if they had never been set; see
@ref{SetBookmark}. If no option is specified, @var{n} is assumed to be
zero. While you can unset the automatic bookmark @samp{-}, it will be
reset automatically to the current position whenever a @code{GotoBookmark}
command is issued. Each document's valid bookmark designations are 0 to 9,
and the  @samp{-} automatic bookmark.



@node Editing Commands
@section Editing Commands

These commands allow modifying a document directly.

@menu
* InsertChar::
* InsertString::
* InsertTab::
* DeleteChar::
* DeletePrevWord::
* DeleteNextWord::
* Backspace::
* InsertLine::
* DeleteLine::
* DeleteEOL::
@end menu



@node InsertChar
@subsection InsertChar
@cmindex InsertChar

@noindent Syntax: @code{InsertChar [@var{code}]}@*
@noindent Abbreviation: @code{IC}

@noindent inserts a character whose @sc{ascii} code is @var{code} at the
current cursor position. @var{code} can be either decimal, hexadecimal if
preceded by @samp{0x}, or octal if preceded by @samp{0}. In any case,
@var{code} must be different from 0. All the currently active preferences
options (insert, word wrapping, auto indent, @i{et cetera}) are applied.

If the optional argument @var{code} is not specified, you can enter it on
the input line, the default being the last inserted character.

Note that inserting a line feed (10) is completely different from inserting
a line with @code{InsertLine}. @code{InsertChar 10} puts the control char
@kbd{@key{Control}-J} in the text at the current cursor position.
See @ref{InsertLine}.

Note also that @code{SaveMacro} converts @code{InsertChar} commands into
a possibly smaller number of @code{InsertString} commands.
This makes macros easier to read and edit. See @ref{SaveMacro}.



@node InsertString
@subsection InsertString
@cmindex InsertString

@noindent Syntax: @code{InsertString [@var{text}]}@*
@noindent Abbreviation: @code{IS}

@noindent inserts @var{text} at the current cursor position. If
the optional argument @var{text} is omitted, you will be prompted for it
on the command line.  All the currently active preferences options
(insert, word wrapping, auto indent, @i{et cetera}) are applied.

Note that @code{SaveMacro} converts @code{InsertChar} commands into a
possibly smaller number of @code{InsertString} commands.
This makes macros easier to read and edit. See @ref{SaveMacro}.




@node InsertTab
@subsection InsertTab
@cmindex InsertTab

@noindent Syntax: @code{InsertTab [@var{n}]}@*
@noindent Abbreviation: @code{IT}

@noindent inserts either @var{n} literal @var{TAB} characters or one or more
spaces sufficient to advance the current cursor position @var{n}
tab stops depending on the @code{Tabs} flag. See @ref{Tabs}, @ref{TabSize}.




@node DeleteChar
@subsection DeleteChar
@cmindex DeleteChar

@noindent Syntax: @code{DeleteChar [@var{n}]}@*
@noindent Abbreviation: @code{DC}

@noindent deletes @var{n} characters from the text. If the optional @var{n}
argument is not specified, it is assumed to be one. Deleting a character
when the cursor is just after the last char on a line will join a line with
the following one; in other words, the carriage return between the two lines
will be deleted. Note that if the cursor is past the end of the current line,
no action will be performed.




@node DeletePrevWord
@subsection DeletePrevWord
@cmindex DeletePrevWord

@noindent Syntax: @code{DeletePrevWord [@var{n}]}@*
@noindent Abbreviation: @code{DPW}

@noindent deletes text from the current position through the first character of the
@var{n}'th previous start-of-word. If the optional @var{n} argument is not specified,
it is assumed to be one (in which case, if the cursor is in the middle of a
word the effect is just to delete to the start of that word).




@node DeleteNextWord
@subsection DeleteNextWord
@cmindex DeleteNextWord

@noindent Syntax: @code{DeleteNextWord [@var{n}]}@*
@noindent Abbreviation: @code{DNW}

@noindent deletes text from the current position to the @var{n}'th next end-of-word
If the optional @var{n} argument is not specified, it is assumed to be
one (in which case, if the cursor is in the middle of a word the effect is
just to delete to the end of that word).




@node Backspace
@subsection Backspace
@cmindex Backspace

@noindent Syntax: @code{Backspace [@var{n}]}@*
@noindent Abbreviation: @code{BS}

@noindent acts like @code{DeleteChar}, but moves the cursor to the left
before deleting each character.




@node InsertLine
@subsection InsertLine
@cmindex InsertLine

@noindent Syntax: @code{InsertLine [@var{n}]}@*
@noindent Abbreviation: @code{IL}

@noindent inserts @var{n} lines at the current cursor position, breaking the
current line. If the optional @var{n} argument is not specified, it is
assumed to be one.



@node DeleteLine
@subsection DeleteLine
@cmindex DeleteLine

@noindent Syntax: @code{DeleteLine [@var{n}]}@*
@noindent Abbreviation: @code{DL}

@noindent deletes @var{n} lines starting from the current cursor
position, putting the last one in the temporary buffer, from which it
can be undeleted. See @ref{UndelLine}. If the optional @var{n} argument is
not specified, it is assumed to be one. Note that this action is in no
way inverse with respect to @code{InsertLine}.



@node DeleteEOL
@subsection DeleteEOL
@cmindex DeleteEOL

@noindent Syntax: @code{DeleteEOL}@*
@noindent Abbreviation: @code{DE}

@noindent deletes all characters from the current cursor position to the end
of the line.

@code{DeleteEOL} could be easily implemented with a macro, but it is such a
common, basic editing feature that it seemed worth a separate implementation.




@node Support Commands
@section Support Commands

These commands perform miscellaneous useful actions. In particular, they
provide access to the shell and a way to assign the functionality of
@key{Escape} to another key.

@menu
* About::
* Alert::
* Beep::
* Exec::
* Flash::
* Help::
* NOP::
* Refresh::
* Suspend::
* System::
* Escape::
* KeyCode::
* NameConvert::
@end menu



@node About
@subsection About
@cmindex About

@noindent Syntax: @code{About}@*
@noindent Abbreviation: @code{About}

@noindent displays the copyright splash screen and places a simple
information line containing the version and build date of @code{ne}
on the status bar. Press any key to dismiss this screen.


@node Alert
@subsection Alert
@cmindex Alert

@noindent Syntax: @code{Alert}@*
@noindent Abbreviation: @code{AL}

@noindent beeps or flashes, depending on the value of the visual bell flag.



@node Beep
@subsection Beep
@cmindex Beep

@noindent Syntax: @code{Beep}@*
@noindent Abbreviation: @code{BE}

@noindent beeps. If your terminal cannot beep, it flashes. If it cannot
flash, nothing happens (but you have a very bad terminal).



@node Exec
@subsection Exec
@cmindex Exec

@noindent Syntax: @code{Exec}@*
@noindent Abbreviation: @code{EX}

@noindent prompts the user on the input line, asking for a command, and
executes it. It is never registered while recording a macro (though the command
you type is).

@code{Exec} is mainly useful for key bindings, menu configurations, and in
manually programmed macros.

Note that if the command you specify does not appear in @code{ne}'s internal
tables, it is considered to be a macro name. See @ref{Macro}.



@node Flash
@subsection Flash
@cmindex Flash

@noindent Syntax: @code{Flash}@*
@noindent Abbreviation: @code{FL}

@noindent acts as @code{Beep}, but interchanging the words ``beep'' and ``flash''.
Same comments apply. See @ref{Beep}.



@node Help
@subsection Help
@cmindex Help

@noindent Syntax: @code{Help [@var{name}]}@*
@noindent Abbreviation: @code{H}

@noindent displays some help about the command @var{name} (both the short and
the long versions of the command names are accepted). If no argument is
given, a list of all existing commands in long form is displayed,
allowing you to choose one. You can browse the help text with the
standard navigation keys. If you press @key{Return}, the command list
will be displayed again. If you press @key{f1} or @key{Escape}, you will
return to normal editing.

Invocations of the @code{Help} command are never registered while
recording macros so that you can safely access the help system while
recording. See @ref{Record}.



@node NOP
@subsection NOP
@cmindex NOP

@noindent Syntax: @code{NOP}@*
@noindent Abbreviation: @code{NOP}

@noindent does nothing. Mainly useful for inhibiting standard key bindings.



@node Refresh
@subsection Refresh
@cmindex Refresh

@noindent Syntax: @code{Refresh}@*
@noindent Abbreviation: @code{REF}

@noindent refreshes the display. @code{Refresh} is very important, and should
preferably be bound to the @kbd{@key{Control}-L} sequence, for historical
reasons. It can always happen that a noisy phone line or a quirk in the
terminal corrupts the display. This command restores it from scratch.

@code{Refresh} has the side effect of checking to see if your window
size has changed, and will modify the display to take that into
account.



@node Suspend
@subsection Suspend
@cmindex Suspend

@noindent Syntax: @code{Suspend}@*
@noindent Abbreviation: @code{SU}

@noindent suspends @code{ne} and returns you to a shell prompt; usually,
the shell command @code{fg} is used to resume @code{ne}.



@node System
@subsection System
@cmindex System

@noindent Syntax: @code{System [@var{command}]}@*
@noindent Abbreviation: @code{SYS}

@noindent asks the shell to execute @var{command}. The terminal is
temporarily reset to the state it was in before @code{ne}'s activation, and
@var{command} is started. When the execution is finished, control
returns to @code{ne}.

If the optional argument @var{command} is not specified, you can enter it on
the input line.

@ignore

Before starting the execution, @code{ne} defines a series of environment
variables which can thus be used on the command line. The variables allow
to refer to parts of the internal state of @code{ne}.

@end ignore



@node Escape
@subsection Escape
@cmindex Escape

@noindent Syntax: @code{Escape}@*
@noindent Abbreviation: @code{ESC}

@noindent toggles the menus on and off, or escapes from the input line. This
command is mainly useful for reprogramming the menu activator, and it is
never registered while recording a macro. See @ref{Record}.



@node KeyCode
@subsection KeyCode
@cmindex KeyCode

@noindent Syntax: @code{KeyCode [@var{k}]}@*
@noindent Abbreviation: @code{KC}

@noindent prompts you to press a key, and reports on the status bar
the key code @code{ne} associates with that key, the
command currently associated with that key code, as well as the
input class for that key code. Input class codes are: ALPHA, COMMAND,
RETURN, TAB, IGNORE, and INVALID. This can be useful while
configuring your @file{~/.ne/.keys} file.

If the optional integer @var{k} (between 0 and 511) is given, @code{KeyCode}
uses @var{k} as the key code and displays the information described above.


@node NameConvert
@subsection NameConvert
@cmindex NameConvert

@noindent Syntax: @code{NameConvert [0|1]}@*
@noindent Abbreviation: @code{NC}

@noindent converts the current document's name between relative and
absolute path names. With no parameter it switches the current name
from relative to absolute, or absolute to relative. With @code{1} it
converts the relative path to absolute or leaves the absolute path
unchanged. With @code{0} it converts the absolute path to relative or
leaves the relative path unchanged.


@node Configuration
@chapter Configuration
@cindex Meta key

In this chapter we shall see how the menus and the key bindings of @code{ne} can
be completely configured. Note that menu and key configuration is parsed at startup
time, and cannot be changed during the execution of the program. This is a
chosen limitation.

We will also see how to override incorrect or missing file name extensions by
comparing the contents of documents to patterns to determine @emph{virtual extensions}.

@ignore
It should also be remarked that the standard configuration of @code{ne} does
not contain key bindings relative to the @key{Meta} key. This choice was forced
by the fact that the behaviour of this key is unpredictable on most systems. If
your @key{Meta} key does what it should (i.e., it rises the high bit of any
character), you can configure about thirty new shortcuts---the
@kbd{@key{Control}-@key{Meta}-@var{letter}} combinations---that will produce
ASCII characters between 128 and 159, and will be parsed as shortcuts by
@code{ne}.
@end ignore

@menu
* Key Bindings::
* Changing Menus::
* Virtual Extensions::
@end menu



@node Key Bindings
@section Key Bindings
@cindex Key bindings
@cindex Configuring the keyboard

@code{ne} allows you to associate any keystroke with any command. To
accomplish this task, you have to create a (possibly UTf-8) file named
@file{.keys} in your @file{~/.ne} directory. You can change
the default name (possibly specifying a complete path) using the
@code{--keys} argument (@pxref{Arguments}).

The format of the file is very simple: each line starting with the @samp{KEY}
sequence of capital characters is considered the description of a key binding.
Each line starting with @samp{SEQ} binds a character sequence to a key.
All other lines are considered comments. The format of a key binding
description is

@example
KEY @var{hexcode} @var{command}
@end example

The @var{hexcode} value is the @sc{ascii} code of the keystroke. (For
special keys such as @key{Insert} or function keys, you should take a
look at the file @file{default.keys} that comes with @code{ne}'s
distribution: it contains a complete, commented definition of
@code{ne}'s standard bindings that you can modify with a trial-and-error
approach.) The easiest way to see the code @code{ne} uses for a given
key is by using the @ref{KeyCode} command. It prompts you to press a
key, then reports the code for that key on the status bar. It also
displays the command bound to that key if there is one.

You can write just the hexadecimal digits, nothing else is
necessary (but a prefixing @samp{0x} is tolerated).  For instance,

@example
KEY 1 MoveSOL
@end example

@noindent binds to @kbd{@key{Control}-A} the action of moving to the start
of a line, while

@example
KEY 101 LineUp
@end example

@noindent binds to the ``cursor-up'' key the action of moving the cursor
one line up.

@var{command} can be any @code{ne} command, including @code{Escape}
(which allows reconfiguring the menu activator) and @code{Macro}, which
allows binding complex sequences of actions to a single keystroke. The binding
of a macro is very fast because on the first call the macro is cached in memory.
@xref{Macro}.

Note that you cannot @emph{ever} redefine @key{Return} or @key{Escape}. This
is a basic issue---however brain damaged is the current configuration, you will
always be able to exploit fully the menus and the command line.

Besides the ``standard'' combinations (e.g.,
@kbd{@key{Control}-@var{letter}}), it possible to program combinations
based on the @key{Meta} key (a.k.a. @key{Alt}). The situation in this
case is a bit more involved, because depending on the terminal emulator you are
using, the effect of the @key{Meta} key can be widely different. For
instance, @code{xterm} raises the eighth bit of a character, so, for
instance,

@example
KEY 81 MoveSOF
@end example

@noindent binds @kbd{@key{Control}-@key{Meta}-a} to the action of moving to the
start of the document. However, @code{gnome-terminal} will emit the
character of ASCII code 1 prefixed with ESC instead (``@code{\x1b\x01}''). To handle this case,
@code{ne} provides codes from 180 on for @emph{simulated @key{Meta}
sequences}: for instance,

@example
KEY 181 MoveSOF
@end example

@noindent binds the abovementioned sequence to the same action as
before. In general, the code 180+@var{x} corresponds to the sequence
ESC followed by the ASCII character of code @var{x}. Note that some of
these sequences may be disabled, if they conflict with existing sequences
of your terminal (for instance, ESC followed by @samp{O} is always
disabled because it prefixes several built-in keyboard sequences).

As a final note, we remark that typing @kbd{@key{Meta}-a} on
@code{gnome-terminal} will produce an ESC followed by @samp{a} (``@code{\x1ba}''). Since it
is obviously easier to press just @key{Meta} rather than @key{Meta} and
@key{Control} at the same time, it is a good idea to associate the same
sequence also to this combination, using

@example
KEY 1E1 MoveSOF
@end example

@noindent Moreover, this setting provides the user with a second choice: one can
press @key{Escape} followed by a letter instead of using modifiers.

This is the approach used by default in @code{ne}: this way,
@key{Control} with @key{Meta} plus a letter should always work, and
@key{Meta} should work sometimes (of course, if you're sure to use
always the same kind of emulator you can bind more features). Again, the
best place to look is the @file{default.keys} file.

As stated above, each line starting with @samp{SEQ} binds a character sequence
to a key code. The format for a @samp{SEQ} binding is

@example
SEQ "@var{sequence}" @var{hexcode}
@end example

@noindent where "@var{sequence}" is a double-quoted string of characters
(which can include escaped hexadecimals) followed by a hexadecimal key code
as described above for @samp{KEY} definitions.

You should rarely need this, as properly configured systems already do
this for most keys. However, some key combinations (@key{Control} in
conjunction with cursor keys for example) are usually not defined. If you
know the character sequence your system generates for such a combination, you may use
@samp{SEQ} to bind that sequence to a particular key code if that sequence
isn't already defined on your system. For example,
@key{Control}-``cursor-left'' may generate the sequence
@code{\x1b[1;5D}. The following lines bind that sequence to the @key{f10}
key code @samp{14A}, then bind that key code to the @samp{HELP} command.

@example
SEQ  "\x1b[1;5D"  14A
KEY  14A          HELP
@end example

Sequences are inherently terminal- or terminal emulator-specific, so
their utility will vary depending on how many emulators you use. At least
they give you the posibility to use keys or key combinations that aren't
covered by @code{curses}.

The key binding file is parsed at startup. If something does not work,
@code{ne} exits displaying an error message. If you want @code{ne} to skip
parsing the key binding file (for instance, to correct the broken
file), just give @code{ne} the @code{--no-config} argument. @xref{Arguments}.



@node Changing Menus
@section Changing Menus
@cindex Configuring the menus

@code{ne} allows you to change the contents of its menus. To
accomplish this task, you have to create a file named @file{.menus} in your
home directory, or in @file{~/.ne}. You can change the default name
(possibly specifying a complete path) using the @code{--menus} argument
(@pxref{Arguments}).

Each line of a menu configuration file not starting with the @samp{MENU} or
@samp{ITEM} keywords is considered a comment. You should describe the menus
as in the following example:

@example
MENU "File"
ITEM "Open...     ^O" Open
ITEM "Close         " Close
ITEM "DoIt          " Macro DoIt
@end example

In other words: a line of this form
@example
MENU "@var{title}"
@end example
will start the definition of a new menu, having the given title. Each line
of the form
@example
ITEM "@var{text}" @var{command}
@end example
will then define a menu item, and associate the given command to it.

Any number of menus can be accommodated, but you should consider that many
terminals are 80 columns wide. There is also a minor restriction on the
items---their width has to be constant throughout each menu (but different
menus can have different widths). Note that the text of an item, as the name of
a menu, is between quotes. Whatever follows the last quote is considered the
command associated to the menu.

@noindent @strong{Warning:} the description of key bindings in menus
(@samp{^O} in the previous example) is very important for the beginner;
there is no relation inside @code{ne} about what you say in the menu and how
you configure the key bindings (@pxref{Key Bindings}). Please do not say
things in the menus that are not true in the key binding file.

The menu configuration file is parsed at startup. If something does not
work, @code{ne} exits displaying an error message. If you want @code{ne} to
skip the menu configuration phase (for instance, to correct the
broken file), just give @code{ne} the @code{--no-config} argument.
@xref{Arguments}.


@node Virtual Extensions
@section Virtual Extensions
@cindex Virtual Extensions
@cindex Extension by Content

When a document is loaded or saved under a different name, @code{ne} may
examine the contents of the document to determine whether to ignore the
corresponding file's actual or missing extension and use instead a @dfn{virtual
extension}. This affects which AutoPrefs and Syntax settings @code{ne}
applies to the document.

The document's contents are matched against the regular expressions (see
@pxref{Regular Expressions}) you include in your @file{~/.ne/.extensions}
file. (There may also be an @file{extensions} file (no leading @samp{.})
in the global directory.) If @code{ne} finds a match it will act as if the
document's name had the corresponding extension.

Note that by default @code{ne} does not override a file's
given extension. However, you can specify any number of extensions that
you would like to allow to be overridden by including lines in your
 @file{~/.ne/extensions} containing only a dot followed by a single extension or
shell ``glob pattern''. In particular, @code{.*"} would
allow overriding all extensions.

@noindent Here's an example @file{~/.ne/.extensions} file:

@example
# The following patterns match some common command interpreters.
# They must match on the first line.
 sh   1  ^#!\s*/.*\b(bash|sh|ksh|zsh)\s*
 csh  1  ^#!\s*/.*\b(csh|tcsh)\s*
 pl   1  ^#!\s*/.*\bperl\b
 py   1  ^#!\s*/.*\bpython[0-9]*\s*
 rb   1  ^#!\s*/.*\bruby\s*
 xml  1  ^<\?xml
# These must match in the first 30 and 1000 lines, respectively.
 yaml   30  ^---$
 ini  1000i ^\[\s*(\w|[.-])+\s*\]\s*$
# You must list the existing extensions you wish to override, one
# per line. Shell glob patterns are allowed. Note that ".*" would
# allow overriding any extension. (Think before you do that!)
.conf
.tx[0-9]
@end example

@noindent The only lines which matter consist of a space-delimited set of
@verbatim
  extension   number   regular_expression
@end verbatim
@noindent or a single @samp{.} followed by a glob pattern. Anything else is treated as a
comment. The number must be a positive integer indicating the maximum line number of the
document in which the corresponding regular expression must match. The exception is zero,
which allows a match on any line in the document. (Actually, ne restricts the examined
portion of the document to the first 1,000,000 bytes.) If the number has a lower-case
@samp{i} suffix (see the @file{ini} example above), the corresponding regular expression
is not case sensitive. Trailing spaces are not included as part of the regular_expression.

Only the last instance of any extension specification is considered. This allows you to
override any specifications from the global @file{extensions} file. If you really need
two different patterns, join them into one by concatenating them with a @samp{|} like so:
@verbatim
  foo  1000i  (pattern_A)|(pattern_B)
@end verbatim


@node Hints and Tricks
@chapter Hints and Tricks
@cindex Escape usage
@cindex Turbo adjustment
@cindex Shortcuts not working
@cindex Meta key
@cindex Changing colors
@cindex Large files

@table @emph

@item Use @key{f1} or @key{Escape}-@key{Escape}, not @key{Escape}.
Due to the limitations of the techniques used when communicating with a
terminal, it is not possible to ``decide'' that the user pressed the
@key{Escape} key for about a second after the actual key press
(@pxref{EscapeTime}). This means that you will experience annoying delays when
using menus. If you have no @key{f1} key, use @key{Escape}-@key{Escape}, or
redefine a keystroke assigning the command @code{Escape}, and you will be
able to use that keystroke instead of @key{Escape}. Unfortunately,
some GUI-based terminals (most notably, @code{gnome-terminal}) use @key{f1}
for their own purposes; in that case, you can assign the @code{Escape}
command to another key (@pxref{Configuration}).

@item Check for the presence of a @key{Meta} key.
If your system has a standard @key{Meta} or @key{Alt} key, there is a
good chance that you have several other shortcuts. If the built-in
@key{Meta} bindings do not work, you must discover which is the effect
of the @key{Meta} in your terminal emulator. Indeed, it is possible in
theory to configure about 150 shortcuts. @xref{Configuration}. In any
case, prefixing a key with @key{Escape} has the same effect as holding
down @key{Meta}, so with the standard key bindings
you can, for instance, advance by word with @kbd{@key{Escape}} followed by @kbd{F}.

@item When editing very large files, please use the @code{--no-syntax} option.
Even if @code{ne} will switch transparently to memory-mapped disk files, syntax
highlighting requires a great deal of additional memory.

@item Mac users should turn on ``Delete sends CTRL-H'' in the @command{Terminal} settings.
If you are a Mac user, you need to check the ``Delete sends CTRL-H'' option
in the @samp{Advanced} tab of the @command{Terminal} application settings.

@item @code{ne} does tilda expansion.
When you have to specify a file name, you can always start with @file{~/} in
order to specify your home directory, or @file{~@var{user}/} to
specify the home directory of another user.

@item It is easy to correct bad colors.
Sometimes, due to different opinions about the best default foreground and
background colors, some of the color choices in a syntax file might be
unreadable (for instance, @samp{dim white} on a terminal with a white
background). Just copy the guilty syntax specification file to the
@file{~/.ne/syntax} directory, and change the color names at the start of
the file.

@item Use the @samp{tabs} syntax to distinguish @sc{tab}s from @sc{space}s.
When you're struggling to clean up a mix of @sc{tab}s and @sc{space}s,
temporarily switching to the @samp{tabs} syntax may help. The command
@command{Syntax tabs} makes @sc{tab} characters show up in a different
background color from @sc{space}s. Once you've gotten your white space
issues straightened out, you can switch back to the syntax appropriate
for your current file type.

@item @code{ne} does interactive filename completion.
When you have to specify a file name as last element of a long input,
you can invoke the completer using @key{Tab}. If you hit it twice in a
row, you will enter the file requester, where you can navigate and
escape back to the command line, either with @key{f1}, which will let
you edit again your previous input, or with @key{Tab}, which will copy
your current selection over your previous file name. In other words, you
can freely alternate completion, editing and browsing.

@item Disable the status bar for slow connections.
@code{ne} tries to emit as few characters as possible when updating the
screen. However, for each key you type it is likely that the status
bar has to be updated. If your connection is very slow, you can
disable the status bar to get a quicker response (@pxref{StatusBar}).

@item The @key{Escape} delay when activating menus can be avoided.
If you press after @key{Escape} any key that does not produce the second
character of an escape sequence, @code{ne} will immediately recognize the
@key{Escape} key code as such. Since non-alphabetical keys have no effect while
browsing through the menus, if you're forced to use @key{Escape} as menu
activator you can press, for instance, @samp{,} just after it to speed
up the menu activation (note that @samp{:} would not work, because it would
activate the command line). Alternatively, you can just type @key{Escape}
twice in a row.

@item Use turbo mode for lengthy operations.
Turbo mode (@pxref{Turbo}) allows performing very complex operations
without updating the screen until the operations are complete. This can
be a major plus if you are editing very long files, or if your terminal
is slow. If the default value (0, which means twice the number of
visible rows) does not give you the best results, experiment other
values.

@item Regular expressions are powerful, and slow.
Regular expressions must be studied very carefully. If you spend a lot
of time doing editing, it is definitely reasonable to study even their
most esoteric features. Very complex editing actions can be performed by
a single find/replace using the @code{\@var{n}} convention. But remember
always that regular expressions are much slower than a normal search: in
particular, if you use them on a UTF-8 text, @code{ne} has to transform
them into an equivalent (but more complex) expression that cannot match
partially a UTF-8 sequence, and this expansion makes the search even
slower.

@item Use the correct movement commands in a macro.
Many boring, repetitive editing actions can be performed in a breeze
by recording them the first time. Remember, however, that while recording
a complex macro you should always use a cursor movement that will apply
in a different context. For instance, if you are copying a word, you cannot
move with cursor keys, because that word at another application of the
macro could be of a different length. Rather, use the next/previous word
keys and the @code{MoveEOW} command, which guarantee a correct behaviour in
all situations.

@item Some preferences can be preserved even with automatic preferences.
When you save an autoprefs file, the file simply contains a macro that,
when executed, produces the current configuration. However, you could want,
for instance, to never change the insert/overwrite state. In this case, just
edit the autoprefs files with @code{ne} and delete the line containing the
command setting the insert flag. When the autoprefs are loaded later, the
insert flag will be left untouched. This trick is particularly useful with
the @code{StatusBar} and @code{FastGUI} commands.

@item If some keystrokes do not work, check for system-specific features.
Sometimes it can happen that a keystroke does not work---for instance,
@kbd{@key{Control}-O} does not open a file. This usually is due to the kernel
tracking that key for its purposes. For instance, along a @code{telnet}
connection with xon/xoff flow control, @kbd{@key{Control}-S} and
@kbd{@key{Control}-Q} would block and release the output
instead of saving and quitting.

In these cases, if you do not need the system
feature you should check how to disable it: for instance, some @sc{bsd}-like
systems feature a delayed suspend signal that is not in the @sc{posix}
standard, and thus cannot be disabled by @code{ne}. On @sc{hp-ux}, the command
@code{stty dsusp ^-} would disable the signal, and would let the control
sequence previously assigned to it to run up to @code{ne}.

@end table



@node Motivations and Design
@chapter Motivations and Design
@cindex Mode
@cindex curses
@cindex POSIX
@cindex terminfo
@cindex termcap
@cindex Magic cookie terminals
@cindex Resource usage
@cindex Interrupt character

In this chapter I will try to outline the rationale behind @code{ne}'s
design choices. Moreover, some present, voluntary limitations of the current
implementation will be described. The intended audience of such a
description is the programmer wanting to hack up @code{ne}'s sources, or the
informed user wanting to deepen his knowledge of the limitations.

The design goal of @code{ne} was to write an editor that is easy to use
at first sight, powerful, and completely configurable. Making @code{ne}
run on any terminal that @code{vi} could handle was also a basic issue,
because there is no use getting accustomed to a new tool if you cannot
use it when you really need it. Finally, using resources sparingly was
considered essential.

@code{ne} has no concept of @emph{mode}. All shortcuts are defined by a
single key, possibly with a modifier (such as @key{Control} or @key{Meta}).
Modality is in my opinion a Bad Thing unless it has a very clear visual
feedback. As an example, menus are a form of modality. After entering the
menus, the alphabetic keys and the navigation keys have a different meaning.
But the modality is clearly reflected by a change in the  user
interface. The same can be said about the input line, because it is always
preceded by a (possibly highlighted) prompt ending with a colon.

@code{ne} has no sophisticated visual updating system similar to, for
instance, the one of @code{curses}. All updating is done while
manipulating the text, and only if the turbo flag is set can some iterated
operations delay the update. (In this case, @code{ne} keeps track in a
very rough way of the part of the screen that changed.) Moreover, the
output is not preempted by additional input coming in, so that along a
slow connection the output could not keep up with the input. However,
along reasonably fast connections, the responsiveness of the editor is
greatly enhanced by the direct update. And since we update the screen in
parallel with the internal representation, we can exploit our knowledge to
output a very small number of characters per modification. As it is
typical in @code{ne}, when such design tradeoffs arise, preference is
given to the solution that is effective on a good part of the existing
hardware and will be very effective on most future hardware.

@code{ne} uses a particular scheme for handling text. There is a doubly
linked list of line descriptors that contain pointers to each line of text.
The lines themselves are kept in a list of pools, which is expanded and
reduced dynamically. The interesting thing is that for each pool @code{ne}
keeps track just of the first and of the last character used. A character is
free iff it contains a null, so there is no need for a list of free chunks.
The point is that the free characters lying between that first and the last
used characters (the @dfn{lost} characters) can only be allocated
@emph{locally}: whenever a line has to grow in length, @code{ne} first
checks if there are enough free characters around it. Otherwise, it remaps
the line elsewhere. Since editing is essentially a local activity, the
number of such lost characters remains very low. And the manipulation of a
line is extremely fast and independent of the size of the file, which can be
very huge. A mathematical analysis of the space/time tradeoff is rather
difficult, but empirical evidence suggests that the idea works.

@code{ne} takes the @sc{posix} standard as the basis for @sc{un*x}
compatibility. The fact that this standard has been designed by a worldwide
recognized and impartial organization such as @sc{ieee} makes it in my
opinion the most interesting effort in its league. No attempt is made to
support ten thousand different versions and releases by using conditional
compilation. Very few assumptions are made about the behaviour of the system
calls. This has obvious advantages in terms of code testing, maintenance, and
reliability. For the same reasons, the availability of an @sc{ansi} C
(C99) compiler is assumed.

If the system has a @code{terminfo} database and the related functions
(which are usually contained in the @code{curses} library), @code{ne} will
use them. The need for a terminal capability database is clear, and the
choice of @code{terminfo} (with respect to @code{termcap}) is compulsory
if you want to support a series of features (such as more than ten
function keys) that @code{termcap} lacks. If @code{terminfo} is not
available, @code{ne} can use a @code{termcap} database, or, as a last
resort, a built-in set of ANSI control sequences. Some details about
this can be found in @ref{Portability Problems}.

@code{ne} does not allow redefinition of the @key{Escape}, @key{Tab} or
@key{Return} keys, nor of the interrupt character
@kbd{@key{Control}-\}. This decision has been made mainly for two
reasons. First of all, it is necessary to keep a user from transforming
@code{ne}'s bindings to such a point that another unaware user cannot
work with it. These two keys and the alphabetic keys allow activating
any command without any further knowledge of the key bindings, so it
seems to me this is a good choice. As a second point, the @key{Escape}
key usage should generally be avoided. The reason is that most escape
sequences that are produced by special keys start with the escape
character. When @key{Escape} is pressed, @code{ne} has to wait for one
second (this timing can be changed with the @code{EscapeTime} command),
just to be sure that it did not receive the first character of an escape
sequence. This makes the response of the key very slow, unless it is
immediately followed by another key such as @samp{:}, or by @key{Escape},
again.  @xref{Hints and Tricks}.

Note that, as has been stated several times, the custom key bindings also work
when doing a long input, navigating through the menus or browsing the
requester. However, this is only partially true. To keep the code size
and complexity down, in these cases @code{ne} recognizes only direct bindings to
commands, and discards the arguments. Thus, for instance, if a key is bound to
the command line @code{LineUp 2}, it will act like @code{LineUp}, while a
binding to @code{Macro MoveItUp} would produce no result. Of course full
binding capability is available while writing text. (This limitation will
probably be lifted in a future version: presently it does not seem to limit
seriously the configurability of @code{ne}.)

@code{ne} has some restrictions in its terminal handling. It does not support
highlighting on terminals that use a magic cookie. Supporting such terminals
correctly is a royal pain, and I did not have any means of testing the code anyway.
Moreover, they are rather obsolete. Another lack of support is for the
capability strings that specify a file to print or a program to launch in
order to initialize the terminal.

The macro capabilities of @code{ne} are rather limited. For instance, you
cannot give an argument to a macro: macros are simply sequences of commands that can be played
back automatically. This makes them very useful for everyday use in a
learn/play context, but rather inflexible for extending the capabilities of the
editor.

@code{ne} has been written with sparing resource use as a basic goal.
Every possible effort has been made to reduce the use of @sc{cpu} time and
memory, the number of system calls, and the number of characters output to
the terminal. For instance, command parsing is done through hash
techniques, and the escape sequence analysis uses the order structure of
strings for minimizing the number of comparisons. The optimal cursor
motion functions were directly copied from @code{emacs}. The update of
files using syntax highlighting is as lazy as possible: modifications
cause just the update of the current line, and the rest of the screen is
updated only when you move away. The search algorithm is a simplified
version of the Boyer-Moore algorithm that provides high performance with a
minimal setup time. An effort has been taken to move to the text segment
all data that do not change during the program execution. When the status
bar is switched off, additional optimizations reduce the cursor movement
to a minimum.

A word should be said about lists. Clearly, handling the text as a
single block with an insertion gap (a la @code{emacs}) allows you to
gain some memory. However, the management of the text as a linked list
requires much less @sc{cpu} time, and the tradeoff seems to be
particularly favorable on virtual memory systems, where moving the
insertion gap can require a lot of accesses to different pages.



@node The Encoding Mess
@chapter The Encoding Mess
@cindex UTF-8
@cindex ISO-8859 family
@cindex ISO-8859-1

@code{ne} supports UTF-8. It can use UTF-8 for its
input/output, and it can also interpret one or more documents as containing
UTF-8 encoded text, acting accordingly. Note that the document content is
actual UTF-8 text---@code{ne} does not use wide characters. As a
positive side-effect, @code{ne} can support fully the ISO-10646
standard, but nonetheless non-UTF-8 texts occupy exactly one byte per
character.

More precisely, @emph{any} piece of text in @code{ne} is classified as
US-ASCII, 8-bit or UTF-8. A US-ASCII text contains only US-ASCII
characters. An 8-bit text sports a one-to-one correspondence between
characters and bytes, whereas an UTF-8 text is interpreted in UTF-8.  Of
course, this raises a difficult question: @emph{when} should a document be
classified as UTF-8?

Character encodings are a mess. There is nothing we can do to change
this fact, as character encodings are @emph{metadata that modify data
semantics}. The same file may represent different texts of different
lengths when interpreted with different encodings. Thus, there is no safe
way of guessing the encoding of a file.

@code{ne} stays on the safe side: it will never try to convert a file
from an encoding to another one. It can, however, interpret data
contained in a document depending on an encoding: in other words,
encodings are truly treated as metadata. You can switch off UTF-8
at any time, and see the same document as a standard 8-bit file.

Moreover, @code{ne} uses a @emph{lazy} approach to the problem: first of
all, unless the UTF-8 automatic detection flag is set
(@pxref{UTF8Auto}), no attempt is ever made to consider a file as UTF-8
encoded.  Every file, clip, command line, etc., is firstly scanned for
non-US-ASCII characters: if it is entirely made of US-ASCII characters,
it is classified as US-ASCII. An US-ASCII piece of text is compatible
with anything else---it may be pasted in any document, or, if it is a
document, it may accept any form of text. Documents classified as US-ASCII
are distinguished by an @samp{A} on the status bar.

As soon as a user action forces a choice of encoding (e.g., an accented
character is typed, or an UTF-8-encoded clip is pasted), @code{ne} fixes
the mode to 8-bit or UTF-8 (when there is a choice, this depends on
the value of the @ref{UTF8Auto} flag). Of course, in some cases this may
be impossible, and in that case an error will be reported.

All this happens behind the scenes, and it is designed so that in 99% of
the cases there is no need to think of encodings. In any case, should
@code{ne}'s behaviour not match your needs, you can always change at run
time the level of UTF-8 support.




@node History
@chapter History
@cindex TurboText
@cindex Amiga

The main inspiration for this work came from Martin Taillefer's
@code{TurboText} for the Amiga, which is the best editor I ever saw on
any computer.

The first versions of @code{ne} were created on an Amiga 3000T, using
the port of the @code{curses} library by Simon John Raybould. After
switching to the lower-level @code{terminfo} library, the development
continued under @sc{un*x}. Finally, I ported @code{terminfo} to the
Amiga, thus making it possible to develop on that platform again. For
@code{ne} 1.0, an effort has been made to provide a @code{terminfo}
emulation using GNU's @code{termcap}.
The development eventually moved to Linux.

Todd Lewis got involved with @code{ne} when the University of North
Carolina's Chapel Hill campus migrated its central research computers
from @sc{mvs} to @sc{unix} in 1995. The readily available @sc{unix} editors
had serious weaknesses in their user interfaces, especially from the
standpoint of @sc{mvs} users who were not too excited about having to move
their projects to another platform while learning an entirely new suite
of tools. @code{ne} offered an easily understood interface with enough
capabilities to keep these new @sc{unix} users productive. Todd installed and
has maintained @code{ne} at UNC since then, making several improvements to the
code to meet his users' needs. In early 1999 his code base and
mine were merged to become version 1.17.

Support for syntax highlighting was added in 2009 with code and
techniques heavily borrowed from the GNU-licensed editor @code{joe},
which was written by Joseph H. Allen. Much of the work to incorporate
this code into @code{ne} was undertaken by Daniele Filaretti, an
undergraduate student working under the direction of Sebastiano at the
Universit@`a degli Studi di Milano.




@node Portability Problems
@chapter Portability Problems
@cindex Portability
@cindex POSIX
@cindex terminfo
@cindex termcap
@cindex Printable characters

This chapter is devoted to the description of the (hopefully very few) problems
that could arise when porting @code{ne} to other flavors of @sc{un*x}.

The fact that only @sc{posix} calls have been used (@pxref{Motivations
and Design}) should guarantee that on @sc{posix}-compliant systems a
recompilation should suffice. Unfortunately, @code{terminfo} has not
been standardized by @sc{ieee}, so that different calls could be
available. The necessary calls are @code{setupterm()}, @code{tparm()}
and @code{tputs()}. The other @code{terminfo} functions are never used.

If @code{terminfo} is not available, the source files @file{info2cap.c}
and @file{info2cap.h} map @code{terminfo} calls on @code{termcap}
calls. The complete GNU @code{termcap} sources are distributed with
@code{ne}, so no library at all is needed to use them. You just have to
compile using one of the options explained in the @file{makefile} and in
the @file{README}. Should you need comprehensive information on GNU
@code{termcap}, you can find the distribution files on any @code{ftp}
site that distributes the GNU archives. I should note that the GNU
@code{termcap} manual is definitely the best manual ever written about
terminal databases.

There are, however, some details that are not specified by @sc{posix}, or are
specified with insufficient precision. The places of the source where such
details come to the light are evidenced by the @samp{PORTABILITY PROBLEM}
string, which is followed by a complete explanation of the problem.

For instance, there is no standard way of printing extended @sc{ascii}
characters (i.e., characters whose code is smaller than 32 or greater than
126). On many system, these characters have to be filtered and replaced with
something printable: the default behaviour is to add 64 to all characters under
32 (so that control characters will translate to the respective letter) and to print
them in reverse video; moreover, all characters between 127 and 160 are visualized
as a reversed question mark (this works particularly well with ISO Latin
1, but Windows users might not like it). This behavior can be easily changed
by modifying the @code{out()} function in @file{term.c}.

Note that it is certainly possible that some system features not standardized
by @sc{posix} interfere with @code{ne}'s use of the I/O stream. Such problems
should be dealt with locally by using the system facilities rather than by
horribly @code{#ifdef}'ing the source code. An example is given in @ref{Hints
and Tricks}.



@node Acknowledgments
@chapter Acknowledgments

A lot of people contributed to this project. Part of the code comes from
@code{emacs} and @code{joe}. Many people, in particular at the silab (the Milan
University Computer Science Department Laboratory), helped in beta testing the
first versions. Daniele Filaretti worked at the integration of syntax-highlighting
code from @code{joe}. John Gabriele suggested several new features and relentlessly tested them.

Comments, complaints, desiderata are welcome.

@example
    Sebastiano Vigna
    Via California 22
    I-20144 Milano MI
    Italia

    sebastiano.vigna@@unimi.it


    Todd M. Lewis
    CB 1150 2210 ITS Franklin
    University of North Carolina
    Chapel Hill, NC 27599-1150
    USA

    Todd_Lewis@@unc.edu


    ne home page: @uref{http://ne.di.unimi.it/}
    Discuss ne at @uref{http://groups.google.com/group/niceeditor/}
    Github repo: @uref{https://github.com/vigna/ne/}

@end example
@page

@page
@node Concept Index
@unnumbered Concept Index
@printindex cp

@page
@node Command Index
@unnumbered Command Index
@printindex cm

@contents
@bye
