Function: _def_colors
Class: default
Section: default
C-Name: sd_colors
Prototype:
Help:
Doc: this default is only usable if \kbd{gp}
 is running within certain color-capable terminals. For instance \kbd{rxvt},
 \kbd{color\_xterm} and modern versions of \kbd{xterm} under X Windows, or
 standard Linux/DOS text consoles. It causes \kbd{gp} to use a small palette of
 colors for its output. With xterms, the colormap used corresponds to the
 resources \kbd{Xterm*color$n$} where $n$ ranges from $0$ to $15$ (see the
 file \kbd{misc/color.dft} for an example). Accepted values for this
 default are strings \kbd{"$a_{1}$,\dots,$a_{k}$"} where $k\le7$ and each
 $a_{i}$ is either

 \noindent\item the keyword \kbd{no} (use the default color, usually
 black on transparent background)

 \noindent\item an integer between 0 and 15 corresponding to the
 aforementioned colormap

 \noindent\item a triple $[c_{0},c_{1},c_{2}]$ where $c_{0}$ stands for
 foreground color, $c_{1}$ for background color, and $c_{2}$ for attributes
 (0 is default, 1 is bold, 4 is underline).

 The output objects thus affected are respectively error messages,
 history numbers, prompt, input line, output, help messages, timer (that's
 seven of them). If $k < 7$, the remaining $a_{i}$ are assumed to be \kbd{no}.
 For instance
 %
 \bprog
 default(colors, "9, 5, no, no, 4")
 @eprog
 \noindent
 typesets error messages in color $9$, history numbers in color $5$, output in
 color $4$, and does not affect the rest.

 A set of default colors for dark (reverse video or PC console) and light
 backgrounds respectively is activated when \kbd{colors} is set to
 \kbd{darkbg}, resp.~\kbd{lightbg} (or any proper prefix: \kbd{d} is
 recognized as an abbreviation for \kbd{darkbg}). A bold variant of
 \kbd{darkbg}, called \kbd{boldfg}, is provided if you find the former too
 pale.

 \emacs In the present version, this default is incompatible with PariEmacs.
 Changing it will just fail silently (the alternative would be to display
 escape sequences as is, since Emacs will refuse to interpret them).
 You must customize color highlighting from the PariEmacs side, see its
 documentation.

 The default value is \kbd{""} (no colors).
