RDF::Query

# RDF::Query - A SPARQL 1.1 Query implementation for use with RDF::Trine.

RDF::Query allows RDQL and SPARQL queries to be run against an RDF model, returning rows of matching results.

## Requirements

To install RDF::Query you'll need the following perl modules installed:

- Data::UUID
- Digest::SHA
- DateTime
- DateTime::Format::W3CDTF
- Error
- File::Spec
- File::Temp
- I18N::LangTags
- JSON
- List::Util
- LWP
- Parse::RecDescent
- RDF::Trine
- Scalar::Util
- Set::Scalar
- Storable
- URI

The following additional modules are recommended for some functionality:

- Geo::Distance

## Installing RDF::Query

To install, run:

perl Makefile.PL
make
make test
make install

## Version History

### Version 2.916 (2015-10-16)

- Enhancements
  - Updated RDF::Query::Node::Resource->as_sparql to allow SPARQL 1.0 PN_LOCAL prefix names (GitHub issue #132).
- Other
  - Add default indentation to RDF::Query::Algebra::Limit->sse.

### Version 2.915 (2015-08-18)

- New Features
  - Add RDF::Query::Node->from_attean method (PR #128 from Kjetil Kjernsmo).
- Other
  - Add default indentation to RDF::Query::Algebra::Limit->sse.

### Version 2.914 (2015-05-17)

- Bug Fixes
  - Fixed bug in evaluation of SPARQL CONCAT function.

### Version 2.913 (2015-02-14)

- Bug Fixes
  - Fix SPARQL 1.1 parsing bug that disallowed whitespace between an aggregate name and the following open-parenthesis.
  - Fix bug in RDF::Query::Algebra::NamedGraph->definite_variables.
  - Fix rqsh to use a pure memory model when requested (instead of a temporary model).
  - Fixed whitespace handling bug during parsing of VALUES clauses (github issue #120).
- Enhancements
  - Merge adjacent service blocks if their endpoints and silent flags match (github issue #124).
  - Allow RDF::Query->new to accept an algebra object instead of a query string.
  - Updated node classes to allow overloaded comparisions with RDF::Trine::Node::Nil objects.
  - Improve coverage of as_hash function for variable bindings and expressions (github issue #121).
- Other
  - Documentation fixes (from Kjetil Kjernsmo).

### Version 2.912 (2014-10-24)

- Bug Fixes
  - Fix bug in handling of SUM aggregates with non-literal data.
- Enhancements
  - Improved performance of regular expression use in SPARQL parser (from Dorian Taylor; github pull request #111).
- Other
  - Added IRC resource to Makefile.PL.

### Version 2.911 (2014-07-24)

- Bug Fixes
  - Fixed bug in RDF::Query::Plan::Join::PushDownNestedLoop that didn't allow 'aggregate' to appear in the RHS serialized text (github issue 101).
  - Fixed SPARQL 1.1 GGP parsing bug (github issue 100).
  - Fixed RDF::Query::Algebra->subpatterns_of_type to support descent into sub-queries.
  - Disabled pushing full updates down into the store object (only meant to be full queries at this point).
  - Fixed as_hash method in RDF::Query::Algebra::Aggregate, RDF::Query::Algebra::Sort, and RDF::Query::Expression::Alias.
  - Updated RDF::Query::Compiler::SQL to respect node class encapsulation.
- Enhancements
  - Modularized implementation of explain method in algebra and plan classes.
  - Updated rqsh script to use env perl instead of hardcoded bin path.
  - Added JSON output to bin/parse.pl script.
  - Added RDF::Query::ExecutionContext->bind_variable method.
- Other
  - Added :all export tag to RDF::Trine::Node.
  - Remove Crypt::GPG and Bloom::Filter from list of recommended modules (no longer used in code).

### Version 2.910 (2013-07-22)

- Bug Fixes
  - Updated RDQL parser to work with recent RDF::Trine releases.

### Version 2.909 (2012-11-24)

- Bug Fixes
  - Fixed bad sparql serialization of filters with equality tests; was using '==' instead of '=' (github issue 53).
  - Fixed bug in RDF::Query::Algebra::Service->referenced_variables.
  - Fixed bug that wasn't passing the active graph to EXISTS filter evaluation.
  - Fixed RDF::Query prepare and execute methods to properly localize the model object.
  - Fixed bug in RDQL parser that mistakenly required a USING clause (github issue 70).
  - Fixed handling of aggregates over empty groups.
- New Features
  - Added support for VALUES graph pattern (in-place BINDINGS).
  - Added support for UUID() and STRUUID() functions.
  - Added is_update() and specifies_update_dataset() methods to RDF::Query.
  - Accept common typo of SEPARATOR in SPARQL 1.1 parser ("SEPERATOR") with constructor arg 'allow_typos' in RDF::Query::Parser::SPARQL11.
- Enhancements
  - Fixed SPARQL 1.1 parsing to enforce not using shared bnode labels between update data operations.
  - Improved SPARQL 1.1 parser detection of invalid use of BIND() (when binding already in-scope variables).
  - Fixed bug in SPARQL 1.1 parser to recognize legal Update operations.
  - Updated SPARQL 1.1 parser to allow colon in local part of a prefixname.
  - Updated STRBEFORE() and STRAFTER() implementations to track SPARQL 1.1 standard.
  - Updated property path implementation to track W3C standard (changed counting semantics and dropped {m,n} form).
  - Added support to passthrough query eval to the model if supported and the 'allow_passthrough' option is set on the query object.
  - Added 'canonicalize' option to RDF::Query constructor to canonicalize literal values.
- Other
  - Updated handling of BIND() in the SPARQL 1.1 parser to match the latest spec semantics.
  - Added ability to run tests of type mf:CSVResultFormatTest.
  - Fixed config handling in rqsh to allow the use of hexastore backends.
  - Merged Log4perl initialization cleanup patches (from github/kba).
  - Use $plan->explain instead of $plan->sse for "explain" rqsh command.
  - Updated EARL IRIs in bin/failing_earl_tests.sh and bin/passing_earl_tests.sh.
  - Removed RDF::Redland recommendation in Makefile.PL.
  - Added doap:implements statements, and updated release data to doap.rdf.
  - Updated RDF::Query::Util::cli_parse_args to allow no-argument setup.
  - Updated xt/dawg/earl.pl to use new EARL IRIs earl:passed and earl:failed.
  - Added POD to bin/rqsh.
  - Updated DAWG test harnesses to support expected query bindings results in RDF/XML format.
  - Fixed xt/dawg-eval11.t to emit TAP failures when query parsing fails.
  - Require RDF::Endpoint 0.05 in xt/dawg-eval11.t.
  - Removed values from test directory list in xt/dawg-eval11.t.
  - Added values to list of test directories in xt/dawg-eval11.t.
  - Added exists test directory to xt/dawg-eval11.t.
  - Added test case confirming bad sparql serialization of equality testing filters (github issue 53).
  - Removed tests for {m,n} property path forms.
  - Fixed RDF::Query::Algebra::Project to throw exception on bad constructor arguments.
  - Added bugtracker info to Makefile.PL.
  - Added POD marking modules as unstable: RDF::Query::BGPOptimizer, RDF::Query::Compiler::SQL, RDF::Query::Federate, RDF::Query::Federate::Plan
  - Improved expected/actual results output when encountering failing tests.
  - Removed old bloom-filter federation code.
  - Removed RDF::Query::ExecutionContext->base method.
  - Fix POD in RDF::Query::Algebra::Table.

### Version 2.908 (2012-01-31)

- Bug Fixes
  - Fixed SPARQL serialization of expressions using && and ||.
  - Fixed SPARQL 1.1 parser to support "GRAPH<iri>" without whitespace.
  - Fixed bug resulting in false positive error when projecting expressions with aggregates.
  - Fixed aggregate evaluation to result in unbound variables on error (instead of dropping the result).
  - Fixed numeric divide operation to return xsd:decimal when operands are xsd:integers.
  - Fixed RDF::Query::Expression::Binary->evaluate to properly throw on div-by-zero.
  - Fixed RDF::Query::Expression::Function->evaluate to propogate type errors in IF().
  - Fixed bin/rqsh to handle queries that use BASE.
  - Fixed bug in RDF::Query::Plan::Join::PushDownNestedLoop that produced invalid results when the RHS was a subselect.
  - Fixed RDF::Query::Algebra::Filter->as_sparql to handle variation of serialization of the child pattern.
  - Fixed bug in SPARQL 1.1 parser that mistakenly introduced aggregate operations in non-aggregate queries.
- New Features
  - Added support for Service as a binary op (allowing variable-endpoint SERVICE blocks).
  - Added implementations for functions STRBEFORE, STRAFTER, and REPLACE.
  - Added RDF::Query->prepare_with_named_graphs method.
  - Added support for COPY and MOVE operations.
  - Allow percent encoding and backslash escaping in prefix names.
- Enhancements
  - Fixed RDF::Query::Expression::Binary to canonicalize numeric literal results.
  - Added syntax support for SILENT form of LOAD.
  - Added support for SILENT and variable endpoint handling for SERVICE patterns.
  - Added syntax support for optional GRAPH keyword on SPARQL 1.1 update shortcuts.
  - Updated RDF::Query::Plan::Extend to copy variable bindings instead of using the existing reference.
  - Added RDF::Query::Plan::Extend->explain.
  - Changed explain() syntax of plan quads.
  - Updated plan classes to optionally register intermediate results with a execution delegate object.
  - Made RDF::Query::Plan::Construct uniq the returned triples.
  - Added custom RDF::Query::Plan::Construct->explain method.
  - Normalize language tags used in SPARQL query syntax to lowercase.
  - Modularize RDF::Query::Plan::Service to allow mock testing.
  - Added exception handling in RDF::Query->set_error.
  - Added subplans_of_type method to Plan classes.
  - Fixed use of '__DEFAULT__' sentinel value in RDF::Query::Plan, RDF::Query::Plan::Service, RDF::Query::Node::Resource->as_sparql, and RDF::Query->as_sparql.
  - Force the planner to avoid using a bind-join when the RHS contains a Service subplan (to avoid a DOS attack on the remote endpoint).
  - Updated DATATYPE() to return rdf:langString on language-tagged literals (per RDF 1.1 change).
  - Fixed sse serialization in RDF::Query::Algebra::Service to handle binary op (variable endpoint) form.
  - Croak rather than die in some places, confess and use logdie in one place
  - Allow aggregates in ORDER BY clause.
- Other
  - Added examples/query_url.pl.
  - Added RDF::Trine::Error::UnimplementedError exception class.
  - Updated required version of RDF::Trine to 0.138.

### Version 2.907 (2011-06-04)

- Bug Fixes
  - Fixed bug in SPARQL 1.1 parser for DESCRIBE queries without a WHERE clause.
  - Fixed join ordering bug for queries with a BINDINGS clause and several joins.
  - Fixed RDF::Query->as_sparql for DESCRIBE queries which project URI terms, not variables.
- Other
  - Fixed expected test results for DESCRIBE queries without a WHERE clause.
  - examples/query.pl now emits a warning if the query object cannot be constructed.

### Version 2.906 (2011-05-14)

- API Changes
  - Globally changed 'base' to 'base_uri' in code and API.
- Bug Fixes
  - Fixed SPARQL serialization in RDF::Query::Plan generation of SERVICE blocks to always include braces around the query body.
  - Fixed SPARQL 1.1 parsing bug in property paths using alternatives ('|').
  - Fixed SPARQL 1.1 bug in parsing prefixnames where a graph term is expected.
  - Fixed bug in ZeroOrMore reverse path handling (patterns matching { var path* term }).
  - Fixed bug in RDF::Query::Node::Literal::_cmp that was causing wrong node comparison results.
  - Fixed bug in parsing solution modifiers in CONSTRUCT and DESCRIBE queries.
  - Fixed bug in handling of unbound variables in delete templates in RDF::Query::Plan::Update.
  - Fixed bug in calls to RDF::Query->var_or_expr_value that was preventing use of EXISTS filters in project expressions.
- New Features
  - Updated RDF::Query::Plan::Iterator->new to allow passing in a callback that will return an iterator, instead of an iterator directly.
  - Updated RDF::Query->query_plan to delegate entire queries to the RDF::Trine::Model when possible.
  - Updated bin/deparse.pl to allow specifying an endpoint url for SPARQL-backed models (which can affect the query plan).
  - Added support for empty SPARQL 1.1 Update sequence operations (allowing no-op updates).
  - Added options to RDF::Query->new to allow forcing RDF::Query to disable query delegation to the underlying store.
  - Added option to RDF::Query::Util::cli_parse_args to specify arbitrary options to be supplied to the RDF::Query->new constructor.
  - Added new, cleaner line-based "explain" format for serializing query Plan and Algebra objects.
  - Added bindings accessor and is_unit method to RDF::Query::Plan::Constant.
  - Added ability to forcibly remove a particular join algorithm from consideration in plan generation.
  - Added 'execute' command in rqsh to allow loading a query from a file or URL.
- Enhancements
  - Updated SPARQL 1.1 parser to prevent bnode use in DELETE blocks.
  - Updated rqsh to associate common filename extensions with media types (helps in loading local files).
  - Updated RDF::Query::Plan::Path to align with new ALP algorithm from the spec text.
  - Added some simple statistics generation code in RDF::Query::Plan::Join subclasses.
  - Added missing implementation for property paths using {n,} modifier syntax.
  - Added code to guard against mishandling unbound/blank/variable nodes in DELETE templates in RDF::Query::Plan::Update.
- Other
  - Updated tests to use new RDF::Trine::Iterator->seen_count method instead of deprecated count method.
  - Updated serialization text for zero-length paths in RDF::Query::Plan::Path->plan_node_data.
  - Removed warning of unknown options passed to RDF::Query->new.
  - Removed unused projection code in RDF::Query->execute_plan.
  - Removed Digest::SHA1 from prereq modules, and updated code to use Digest::SHA instead.
  - Remove the meaningless "All rights reserved" copyright text.
  - Fixed test count in t/sparql11-propery_paths.t.
  - Commented out noisy debugging output in RDF::Query::Plan::Path.
  - Added trace debugging in RDF::Query::Plan::Sort.
  - Added options instance variable to RDF::Query::ExecutionContext.
  - Added Module::Pluggable to list of required modules in Makefile.PL.
  - Added mappings from file extensions to media types in dawg test scripts.
  - Various updates to SPARQL 1.1 dawg test harness scripts.

### Version 2.905 (2011-02-18)

- Bug Fixes
  - Fixed mistaken case sensitivity of COALESCE, BNODE, CONCAT, and SUBSTR keywords in SPARQL 1.1 parser.
  - Fixed parsing ambiguity between MIN aggregate and MINUTES function.
  - Fixed Xpath fn:timezone-from-dateTime function return for UTC timezones.
  - Fixed RDF::Query::Algebra::Project->as_sparql handling of binary select expressions.
  - Fixed RDF::Query::Algebra::Construct->sse serialization to include construct triples.
  - Updated handling of BIND() to not close group scope (which was applying filters in the wrong place).
  - Fixed RDF::Query::Parser::SPARQL11 to handle whitespace between tokens in 'INSERT DATA' and 'DELETE DATA'.
  - Fixed RDF::Query::Parser::SPARQL11 to handle empty ModifyTemplates.
  - Fixed SPARQL 1.1 parser to properly set relevant datasets for update operations.
  - Fixed plan code for zero-length paths to return RDF::Query::Node-based results (not Trine-based).
  - Fixed bug in RDF::Query::Plan::Clear when attempting to clear the default graph.
  - Fixed exception throwing on numeric binary expression eval without numeric literal arguments.
  - Updated RDF::Query::Plan to handle update operations with different datasets for matching (USING clause).
- New Features
  - Added SPARQL 1.1 numeric functions: ABS, CEIL, FLOOR, ROUND, RAND
  - Added SPARQL 1.1 string functions: CONCAT, SUBSTR, STRLEN, UCASE, LCASE, ENCODE_FOR_URI, CONTAINS, STRSTARTS, STRENDS
  - Added SPARQL 1.1 date functions: NOW, TIMEZONE, TZ, YEAR, MONTH, DAY, HOURS, MINUTES, SECONDS
  - Added SPARQL 1.1 hashing functions: MD5, SHA1, SHA224, SHA256, SHA384, and SHA512
  - Added RDF::Query::Functions->install_function method, and implementations for fn:compare, fn:concat, and fn:substring.
  - Updated RDF::Query->execute_with_named_graphs to accept optional arguments to be passed to execute().
  - Added support for CONSTRUCT WHERE syntax shortcut.
  - Added support for SILENT modifier to SERVICE patterns.
  - Added SILENT flag in RDF::Query::Algebra::Service.
  - Added initial code to create SPIN serializations of queries.
  - Added RDF::Query::Node::Literal->type_list method.
- Enhancements
  - Updated xt/dawg-syntax11.t to find more syntax queries in the dawg test data.
  - SPARQL 1.1 parser now throws errors for more classes of syntactically invalid queries (repeated expression aliases, wrong number of BINDINGS values, SELECT * with use of grouping).
  - Added support for non-strict comparisons of xsd:strings in RDF::Query::Node::Literal (based on $LAZY_COMPARISONS variable).
- Other
  - Major refactor of xt/dawg-eval11.t test harness.
  - Updated required version of Test::More to 0.88 (0.86 doesn't have done_testing() used in t/store-config.t).
  - Updated RDF::Query::Expression::Function->evaluate to throw an error if no function coderef is found.

### Version 2.904 (2010-11-23)

- Added 'set prefix' and 'time' commands to rqsh.
- Added string concatenation overloading of binary +.
- Fixed bug in property path evaluation on encountering blank path nodes.
- Fixed use of binary '*' in FILTER without numeric data in t/resultforms.t.
- Fixed bin/dawg11-status.pl to only load SPARQL 1.1 earl result files.
- Fixed RDF::Query::Plan::Update to ignore non-ground triples (unbound variables don't act as wildcards).
- Fixed handling of named graph data in insert/delete patterns of update operations.
- Updated RDF::Query::Util to use RDF::Trine::Model->temporary_model and guess an appropriate parser based on filenames.
- Updated namespace URI in RDF::Query::Functions::Jena to <http://jena.hpl.hp.com/ARQ/function#>.
- Updated namespace URI in RDF::Query::Functions::Xpath to <http://www.w3.org/2005/xpath-functions#>.
- Updated xt/dawg-eval11.t to align with updated test case manifest schemas.
- Updated xt/dawg-eval11.t to prevent test cases with missing files from emitting failures (now skipped).
- Added xpath function implementations.
- Added SPARQL 1.1 Update shortcut syntax support for COPY, MOVE, and ADD graph operations.
- Fixed bug in RDF::Query::Plan::Construct that wasn't giving each result a new set of blank nodes (RT 63155).
- Updated SYNOPSIS and execute() and execute_plan() methods POD (RT 63153 comment from Ivan Shmakov).
- Updated documentation to explicitly discuss inherited methods due to subclassing.
- Fixed RDF::Query::Algebra::Sequence->sse to serialize operations in proper order.
- Added $silent argument to RDF::Query::Algebra::Clear constructor.

### Version 2.903 (2010-11-03)

- SPARQL 1.1
  - New features
    - Added support for BIND(expr AS ?var) operator.
    - Added isNumeric built-in function, checking for proper datatype and valid lexical forms for numerics.
  - Updates
    - Updated SPARQL 1.1 parser to handle WITH clauses with PrefixedNames.
    - SPARQL 1.1 parser now sets error and returns if no query string is supplied.
    - Added more exception handling in RDF::Query::Parser::SPARQL11.
    - Updated CLEAR and DROP handling in SPARQL 1.1 parser and engine to handle 'NAMED' and 'ALL' variants.
    - Renamed 'binding_variables' methods to 'potentially_bound' to align with current SPARQL 1.1 terminology.
    - Results returned by property path plans are now RDF::Query::VariableBindings objects and are properly projected.
    - The query planner now interprets simple paths as basic graph patterns.
    - Removed Algebra and Plan classes for Not and Exists operations (now handled in other classes).
    - Updated RDF::Query::Plan::Extend to drop the extended variable binding if evaluating the extension yields an error.
    - Updated RDF::Query::Plan::Update to accept delete patterns with variables.
    - Updated subquery plan objects to use a sub-plan, not a full query object.
  - Bug fixes
    - Fixed SPARQL 1.1 parser bug that was returning partial data from a failed parse call.
    - Fixed SPARQL 1.1 parser bug for queries with multiple FILTERs in a GGP including an EXISTS filter.
    - Fixed SPARQL 1.1 parser bug for DROP/CLEAR queries.
    - Fixed SPARQL 1.1 parser typo of 'SEPARATOR' argument to GROUP_CONCAT aggregate.
    - Fixed SPARQL 1.1 parser to handle FITLERS to the left of MINUS/OPTIONAL and allow projecting '*' with other vars/epressions.
    - Fixed SPARQL 1.1 parser case sensitivity of project expression 'AS' token.
    - Fixed SPARQL 1.1 parser handling of of subqueries within GRAPH blocks.
    - Fixed miscellaneous bugs and improved performance of parsing SPARQL 1.1 queries.
    - Made parsing of very large triple blocks non-recursive in SPARQL 1.1 parser.
    - Fixed COALESCE function to handle errors properly.
    - Fixed RDF::Query::Plan::Aggregate to extend results using AliasExpressions from HAVING clauses.
    - Fixed bug that was ignoring GROUP BY clauses when no aggregate operations were present.
    - Fixed bad looping on start node of unbounded property paths.
    - Fixed bug in query planning of '^' property paths.
    - Fixed zero-length property path evaluation within GRAPH blocks.
    - Removed plan duplication of zero-length case in '*' property paths.
    - Fixed handling of named graphs within subqueries (changes to active graph handling in the query planner).
    - Fixed type-promotion and handling of numeric types in aggregate handling.
    - Fixed RDF::Query::Algebra::Update->as_sparql to handle INSERT/DELETE updates properly.
    - Fixed RDF::Query::Plan::Aggregate->sse to allow handling of (non-blessed, scalar) '*' columns.
- Query Engine
  - Added ability to pass through arguments to the query planner in RDF::Query->prepare.
  - Updated RDF::Query::Node::Literal::_cmp to handle literals that fail to parse as DateTime objects.
  - Updated RDF::Query::Plan::Limit to use the limit accessor internally.
  - RDF::Query::Plan::NamedGraph now uses lazy iterator for graph names.
  - Updated RDF::Query::VariableBindings to subclass the new RDF::Trine::VariableBindings.
  - RDF::Query::Algebra::Project now implements bind_variables().
  - Updated RDF::Query->describe to use $model->bounded_description instead of simply outgoing arcs.
  - Fixed bug in evaluation of function expressions in which the execution context object was lost (causing EXISTS filters to fail).
  - Fixed optimization of COUNT(*) over 1-triple BGPs to keep the variable binding for the pseudo-variable ?COUNT(*).
  - Fixed sse serialization in RDF::Query::Algebra::Distinct.
  - Fixed RDF::Query::Plan::Join::PushDownNestedLoop to close sub-plans in close() method.
- rqsh - RDF::Query Shell
  - Added ability to show the parsed algebra with 'parse' command.
  - Added abiility to show the query execution plan with the 'explain' command.
  - Added ability to change the RDF serializer with the 'serializer' command.
  - Added ability to initialize new stores with the 'init' command.
  - Added ability to change underlying store with the 'use' command.
  - Added 'help' command.
  - Updated packaging to install rqsh script (renamed from old bin/rqsh.pl).
  - Updated to catch errors thrown while trying to create new storage backends (e.g. DBI->connect failing).
  - rqsh now defaults to read-write models.
  - rqsh now sets a base URI for the current working directory.
  - Password input now doesn't echo to the terminal.
  - Filename input now autocompletes via Term::ReadLine.
- Warning and Error Handling
  - Replaced calls to die with throwing exceptions.
  - RDF::Query->new now warns about unrecognized options.
  - DATATYPE() now throws an exception unless passed a valid node object.
  - RDF::Query::Expresion::Binary now throws exceptions on numeric comparisions with non-numeric operands.
  - Fixed error message in RDF::Query::Plan::NamedGraph.
  - Added trace debugging to RDF::Query::Plan::Union.
  - Added trace debugging to RDF::Query::Plan::Project.
  - Added trace debugging to RDF::Query::Plan::Path.
- Tests and Miscellany
  - Added SPARQL 1.1 syntax and eval test harnesses.
  - Fixed bug in xt/dawg-eval11.t parsing of srx files containing literal values that evaluate to false in perl (e.g. '0').
  - Fixed turtle output for rdfs:comments in xt/dawg/earl.pl.
  - Moved developer tests from t/ to xt/.
  - Refactored RDF::Query::Functions into several auto-loaded sub-packages via Module::Pluggable (patch from tobyink).
  - Removed references to the now-deprecated mac.com in network-based tests.
  - Updated expected values in t/queryform-describe.t for results using bounded descriptions.
  - Updated RDF::Query::Util to look for .prefix-cmd cache of common namespace names.
  - Updated RDF::Query::Util::cli_parse_args to accept '-r' as a read-only flag.
  - Updated required version of RDF::Trine to 0.126.
  - Updated to use URI 1.52 to allow direct usage of IRIs without unicode workarounds.
  - Made code updates to improve performance based on profiling.

### Version 2.902 (2010-07-02)

- Fixed bug in requiring prerequisite modules.

### Version 2.901 (2010-06-29)

- Fixed named graph handling.
- Fixed bug in handling of * aggregates.
- Simplified code to create new temporary models when FROM clauses dereference graph data.
- Added support for SPARQL 1.1 CREATE/DROP GRAPH update operations.
- Fixed infinite loop bug on parsing certain invalid SPARQL 1.1 update queries.
- Fixed handling of BGPs within named graphs in RDF::Query::Plan::BasicGraphPattern.
- Updated syntax error exception messages in SPARQL parsers.
- Fixed property path evaluation within named graphs.
- Converted Makefile.PL to properly use Module::Install.

### Version 2.900 (2010-06-23)

- Major Changes
  - SPARQL 1.1 is now the default query parser.
  - RDF::Core is no longer supported as a backend triplestore.
  - Redland is still supported as a backend store, but updated handling of default and named graphs means that existing triples stored in Redland without a context (named graph) will not be accessible from RDF::Query.
- SPARQL Language Updates
  - Added support for SPARQL 1.1 Query features:
    - Basic Query Federation with BINDINGS and UNDEF support.
    - Functions: IF, STRDT, STRLANG, IRI, URI, BNODE.
    - Infix operators IN and NOT IN.
    - Aggregates COUNT, SUM, MIN, MAX, AVG, GROUP_CONCAT, and SAMPLE.
    - Property paths.
    - Negation with MINUS graph patterns and NOT EXISTS filters.
  - Added support for SPARQL 1.1 Update features:
    - INSERT/DELETE DATA, INSERT/DELETE WHERE, LOAD, and CLEAR
    - Added support for multi-statement updates.
- API Updates
  - Removed all bridge classes (RDF::Query::Model::*).
  - Removed RDF::Query::Logger class.
  - Removed net filter function code from RDF::Query.
  - Added as_hash method to Query, Algebra, and Node classes.
  - Removed SPARUL and SPARQLP parsers.
  - RDF::Query no longer loads URIs in FROM and FROM NAMED clauses with SPARQL 1.1 by default.
  - Added ability for RDF::Query::Plan::Iterator to fire a callback when execute() is called.
  - Added new RDF::Query::Plan::ComputedStatement class.
  - Added new RDF::Query::Plan::Iterator class.
- Bugfixes
  - Fixed whitespace unescaping bug in SPARQL (1.0 and 1.1) parsers.
- Scripts
  - Added bin/json.pl to print a JSON-formatted representation of the query algebra.
  - Added bin/rqsh.pl CLI interface to executing updates and queries.
  - Added ability to serialize algebra and plan in bin/deparse.pl.
  - bin/deparse.pl now catches parsing errors and prints stacktrace.
- Optimizations
  - Implemented optimization for COUNT(*) over a single triplepattern.

### Version 2.202 (2010-05-22)

- Added initial SPARQL 1.1 syntax and eval support for select expressions, subqueries, negation, aggregates, subqueries, and basic federation.
- Added RDF::Query::VariableBindings.pm->set method.
- Added RDF::Query::_new constructor without any sanity or setup code (used for subquery construction).
- Added RDF::Query::Node::Blank::new constructor to avoid RDF::Trine's N-Triples syntax requirements.
- Added SAMPLE and GROUP_CONCAT aggregate support.
- Added shortcut functions for constructing RDF::Query::Node objects and Algebra Triples, BGPs and GGPs.
- Added warning to RDF::Query::Algebra::Project constructor for improper variable lists.
- Updated DAWG tests to use SPARQL 1.1 parser.
- Removed SPARQLP aggregate tests that don't align with new SPARQL 1.1 semantics.
- Updated DAWG eval tests to skip non-approved tests.
- Fixed handling of unicode decoding in DAWG eval tests.
- Bumped required version of RDF::Trine to 0.123.
- Updated t/models.pl to use RDF::Trine::Parser->parse_url_into_model method and redland's 'guess' parser.
- Fixed logging key name in RDF::Query::Plan::Exists.
- Fixed sse and as_sparql methods in RDF::Query::Algebra::Exists.
- Implemented RDF::Query::Algebra::Exists::binding_variables.
- Updated BGPOptimizer to estimate selectivity directly instead of using costmodel code.
- Removed costmodel code.
- Removed unused fixup and execute methods in Algebra classes.
- Updated RDF::Query to only instantiate DateTime parser and LWP::UserAgent if needed.
- Changed DBPedia network test to align with recent DBPedia update in t/dev-service-description.
- Updated SPARQLP parser tests to align with internal changes in RDF::Query::Algebra::Aggregate.
- Updated RDF::Query::Algebra::Aggregate and RDF::Query::Plan::Aggregate to syntactically handle HAVING clauses.
- Fixed bin/graph-bgp.pl (had bitrotted).
- Changed bnodes to named variables in examples/queries/sparql-bgp-people-knows.rq.
- RDF::Query::Util::cli_make_query now defaults the 'class' parameter to 'RDF::Query'.
- Removed dependency list and added perlrdf link to POD in RDF::Trine and RDF::Query.

### Version 2.201 (2010-01-30)

- Added benchmark/lubm.pl.
- Added examples/queries/sparql-ask-people.rq.
- Added RDFa tests.
- Added Data::UUID prerequisite to META.yml and Makefile.PL.
- Updated ::Model::RDFTrine::add_uri and ::add_string to use new RDF::Trine::Parser methods.
- Updated as_sparql and sse code to work with more recent RDF::Trine versions.
- Removed as_sparql caching in RDF::Query::Algebra::Triple.
- Renamed RDF::Query test files to remove old-style numbering.
- Updated parser tests to track new RDF::Trine::Node::Literal internal structure.
- Updated prereq version of RDF::Trine to 0.114.
- Fixed NAME POD section in RDF::Query::ServiceDescription (RT52264 from KjetilK).

### Version 2.200 (2009-08-06)

- Federation / Service Descriptions
  - Rewrote the optimistic plan generator in RDF::Query::Federate::Plan.
  - Added threshold timeout argument to RDF::Query::Plan::ThresholdUnion and support for it in RDF::Query::Federate::Plan.
  - Simplified logging in RDF::Query::Federate::Plan (now only logs to category 'rdf.query.federate.plan').
  - RDF::Query::ServiceDescription now adds an 'origin' label annotations to RDF::Query::Algebra::Triple objects.
  - Removed check of the sd:definitive property in RDF::Query::ServiceDescription (was based on wrong assumptions).
  - Updated RDF::Query::ServiceDescription::answers_triple_pattern() to recognize wildcard capabilities, constructor now adds wildcard by default.
  - Added new RDF::Query::ServiceDescription::new_with_model constructor.
  - RDF::Query::ServiceDescription::computed_statement_generator now returns empty iterators when passed triple patterns with bound blank nodes.
  - Added test data in data/federation_data/.
  - RDF::Query::Plan::Service now adds an 'origin' label annotation to the RDF::Query::VariableBindings object.
  - Added 'optimistic_threshold_time' query flag to RDF::Query::ExecutionContext and RDF::Query constructor.
  - RDF::Query::Federate::add_service() now adds the appropriate computed statement generators to the query object.
  - Removed optimistic query rewriting test from t/34-servicedescription.t (now covered by t/federate.t).
  - Added t/federate.t with tests for optimistic federated query optimization using ::Plan::ThresholdUnion and RDF::Endpoint::Server.
- Aggregates
  - Fixed serialization quoting issue in RDF::Query::Algebra::Aggregate::sse().
  - RDF::Query::Plan::Aggregate now attempts plain string comparisons for MIN,MAX when strict_errors is not set.
  - Added support for average aggregates, and fixed datatype support in aggregates.
- Command Line Inferface
  - Added bin/query.pl, a fork of examples/query.pl, to support simple query execution.
  - Added RDF::Query::Util as home to helper functions (added CLI args parsing functions to create queries and models).
  - Simplified CLI argument parsing in bin/ and examples/ programs.
- Refactoring, Code Cleanup, and Documentation
  - Added and updated POD to RDF::Query::Util, RDF::Query::Node and RDF::Query::Plan and RDF::Query::Federate::Plan.
  - Added check for RDFQUERY_THROW_ON_SERVICE environment variable in RDF::Query::Plan::Service.
  - Cleaned up code in RDF::Query::Model::get_computed_statements().
  - Updated SSE formatting and uninitialized warning in RDF::Query::Plan, RDF::Query::Algebra::Filter, RDF::Query::Algebra::Distinct and RDF::Query::Algebra::Sort.
  - Moved shared RDF::Trine-related model methods into RDF::Query::Model from subclasses.
  - Raised required RDF::Trine version to 0.111 which brings RDF::Trine::Graph support.
  - RDF::Query::Model::RDFTrine::BasicGraphPattern::execute now returns $self.
  - Removed dependency on Test::JSON, List::MoreUtils, and XML::Parser.
  - Removed TODO on test in t/29-serialize.t.
  - Removed unnecessary code in RDF::Query::Plan subclasses, bin/query.pl, bin/graph-bgp.pl and bin/graph-query.pl.
- Logging
  - Added logging in RDF::Query::Plan::ThresholdUnion, and RDF::Query::Model.
  - Changed logging level from debug to trace in RDF::Query::Plan::Triple, RDF::Query::Plan::Project, RDF::Query::Plan::Filter, RDF::Query::Plan::Join::NestedLoop, RDF::Query::Plan::PushDownNestedLoop, and RDF::Query::Model::RDFTrine.
  - Added calls to Log::Log4perl::is_debug to eliminate unnecessary serialization of logging when not in use.
  - Made error message more useful when SERVICE calls fail in RDF::Query::Plan::Service.
- Bugfixes
  - Fixed bug in RDF::Query::Plan::Offset in cases where the offset was beyond the end of the result set.
  - Fixed testing for Bloom::Filter in t/31-service.t.
  - Fixed test expectations when making remote DBPedia query in t/34-servicedescription.t.
  - Fixed check of $ENV{RDFQUERY_NETWORK_TESTS} to test boolean value, not just existence.
  - Fixed (bad) expected serializations in t/29-serialize.t.
  - Fixed bug in RDF::Query::Plan::ThresholdUnion attempting to close an iterator twice.
  - Fixed sse serialization issues in RDF::Query::Algebra::BasicGraphPattern and RDF::Query::Algebra::Project.
  - Fixed bug in RDF::Query::Node::from_trine() that up-cast blank nodes to variables.
  - Fixed quoting issue in RDF::Query::Algebra::Service::sse().
  - Fixed parameter handling in bin/graph-qeps.pl:prune_plans().
  - Fixed handling of 'GRAPH ?g {}' (empty GraphGraphPatterns) to return all graph names.
  - Added check for ref($node) in RDF::Query::VariableBindings::new (broke code after previous removal of blessed() check).
  - Added use of defined() in code that had been testing boolean value of objects (and causing expensive string overloading).
- Miscellaneous Changes
  - Added examples of queries and service descriptions in examples/.
  - Updated dawg-eval.t to actually test graph equivalence.
  - Clarified graph labels in RDF::Query::Model::RDFTrine::BasicGraphPattern::graph().
  - Added the ability to add label annotations to RDF::Query::VariableBindings, RDF::Query::Algebra::Triple and RDF::Query::Algebra::Quad objects.
  - RDF::Query::Plan::Quad and RDF::Query::Plan::Triple now add an 'origin' label annotation to the RDF::Query::VariableBindings object if the underlying statement has one.
  - RDF::Query::Plan::prune_plans now uses a stable sort when comparing plan costs.
  - RDF::Query::Algebra::Triple::new now up-casts to RDF::Query node objects, if necessary.
  - RDF::Query::Model::RDFTrine::generate_plans now respects the force_no_optimization query flag.
  - RDF::Query::Algebra::BasicGraphPattern::sse() now sorts triples for output.
  - Added distinguish_bnode_variables method to RDF::Query::Algebra::Quad and RDF::Query::Algebra::Triple.
  - Added RDF::Query::Node::Blank::make_distinguished_variable method.
  - Added caching of sparql serializations to RDF::Query::Algebra::BasicGraphPattern and RDF::Query::Algebra::Triple.
  - Added code to RDF::Query::VariableBindings::new to up-cast any RDF::Trine::Node objects to their RDF::Query equivalents.
  - RDF::Query::new() now looks for $args{ defines }, and adds them to the internal %options HASH.
  - Added hook in RDF::Query::execute_plan() to print the query plan to STDERR if $options{plan} is set (can be set if defines).
  - Updated RDF::Query::Plan to only consider model-specific plans (if there are any).

### Version 2.100 (2009-03-18)

- API
  - Added ::Algebra::BasicGraphPattern::connected method.
  - Added 'node_counts' as a recognized key to ::Model::RDFTrine::suports().
  - Added ::Model::node_count method.
  - Added ::Model::RDFTrine::count_statements() and ::Model::RDFTrine::node_count() methods.
  - Added 'store' field to the data returned by the meta() method in the ::Model::* classes.
  - Added a peek method to ::Iterator to support execution deferment like in ::Algebra::Service.
  - Added ability to force SERVICE calls to abort using $ENV{RDFQUERY_THROW_ON_SERVICE} and RequestedInterruptError.
  - Added bf methods to ::Triple and ::BasicGraphPattern to describe the BGP in terms of bound/free.
  - Added bind_variables method to RDF::Query::Algebra.
  - Added caching to ::Algebra::Service::_names_for_node.
  - Added code to count (and warn) the rate of false positives from a bloomjoin.
  - Added cost model hooks in RDF::Query and ::Algebra::BasicGraphPattern.
  - Added FeDeRate BINDINGS to the list of supported extensions.
  - Added get_basic_graph_pattern to ::Model::RDFTrine (not used yet).
  - Added is_solution_modifier() methods to ::Algebra classes.
  - Added labels and common patterns to service description template.
  - Added more logic and debugging to aggregating triples into BGPs for SERVICE calls.
  - Added optional restriction argument to ::Algebra::subpatterns_of_type.
  - Added RDF::Query::Model::RDFTrine::BasicGraphPattner::graph() method.
  - Added RDF::Query::Node::compare for sorting (either Trine or Query) node objects.
  - Added RDF::Query::plan_class so that ::Federate can overload calls to ::Plan methods.
  - Added support for computed statement generators (like ARQ's computed property support [e.g. list:member]).
  - Added trial subsumes() methods to ::Algebra::BasicGraphPattern and ::Algebra::Triple.
  - Algebra classes now call RDF::Query::algebra_fixup for optimization before falling back on normal fixup code.
  - Allow equality test and disjunction filters in patterns that can be compiled to SQL.
  - Fixed ::Algebra::GroupGraphPattern to use join_bnode_streams in cases where the bloom filter wasn't automatically created but instead provided by the user.
  - Fixed ::Model::RDFTrine::as_string use with Quads.
  - Fixed argument list for RDF::Query::Algebra::Service::_names_for_node called from bloom function.
  - Fixed bug so ::Model::RDFTrine::meta may be called as a class method.
  - Fixed RDF::Query::algebra_fixup to ignore service capabilities that would result in empty BGPs.
  - Modified code for aggregate queries (though they are currently broken).
  - Moved construction of bloom-filter-optimized patterns to RDF::Query::Algebra::GroupGraphPattern::_bloom_optimized_pattern().
  - Moved initial federated service code into RDF::Query::fixup and ::algebra_fixup.
  - Moved QEP generation code to RDF::Query::query_plan so it can be overloaded.
  - Moved RDF::Query::add_service() to RDF::Query::Federate::add_service().
  - Parsing service descriptions now more forgiving in the face of missing values.
  - RDF::Query::Algebra::Triple::new now adds RDF::Query::Node::Variable objects for undefined nodes.
  - RDF::Query::fixup() now only returns a construct pattern (the query pattern now being returned by RDF::Query::query_plan()).
  - RDF::Query::Model::get_computed_statements now doesn't die if there's no query object present.
  - RDF::Query::new() now accepts two-argument form with just $query and \%options.
  - RDF::Query::Node::Literal objects now can compare as equal when they're of numeric type but the lexical values aren't numeric.
  - RDF::Query::prune_plans now takes ExecutionContext as an argument, and in turn calls ::Plan::prune_plans.
  - RDF::Query::query_plan() now returns all possible query plans when called in list context.
  - RDF::Query::query_plans now calls RDF::Query::prune_plans to select from the list of possible QEPs.
  - RDF::Trine::Node::Resource now escapes unicode in base URIs (now just relative URI part) before calling URI->new_abs.
  - Removed now unused RDF::Query::construct() and RDF::Query::fixup().
  - Removed old execute() code from ::Algebra classes.
  - Removed unused redland fallback code from RDF::Query::Model::RDFTrine.
  - Split RDF::Query::execute into prepare() and execute_plan() methods.
  - Converted RDF::Query::execute() to use ::Plan classes.
  - Updated ::Compiler::SQL to recognize ::Algebra::Project objects.
  - Updates to RDF::Query::execute() to support explicit pre-binding lists (instead of just scalar values).
  - ::Algebra::GroupGraphPattern now throws an exception if passed unblessed values as patterns.
  - ::Federate now labels nodes in the QEP tree with applicable services.
  - ::Model::debug() now shows data from the named graph model.
  - ::Model::RDFTrine::add_uri now decodes resulting content as utf8 before proceeding.
  - ::Model::RDFTrine::meta() probes the underlying store object to declare the proper 'store' class.
  - ::Service::_names_for_node updated to use ::Plan classes for query execution (fixes use of the k:bloom filter).
- Classes
  - Added algebra classes for solution modifiers and query forms (construct, project).
  - Added code and tests for Query Execution Plan classes RDF::Query::Plan::*.
  - Added RDF::Query::Federate::Plan for federation-specific code.
  - Added RDF::Query::BGPOptimizer implementing a basic optimizer for basic selectivity-based join ordering.
  - Added RDF::Query::CostModel classes for computing/estimating the cost of executing a specific pattern.
  - Added RDF::Query::ExecutionContext to hold all necessary information for query execution (query, model, bound variables).
  - Added RDF::Query::ServiceDescription for parsing DARQ-style service descriptions.
  - Added RDF::Query::VariableBindings to wrap existing HASH-based variable binding structure.
  - Added stub ::Plan::ThresholdUnion class for running optimistic queries.
  - Added workaround to RDFCore bridge so that RDF::Core doesn't die if getStmts is called with a Literal in the subj or pred position.
  - Added a RequestedInterruptError exception class.
  - Added code for RDF-Trine specific BGP query plans.
  - Changed debugging in RDF::Query modules to use Log::Log4perl.
  - Made SERVICE work again by rolling back streaming socket work (now commented out).
  - Moved federation code to new RDF::Query::Federate class.
  - Plan generation now includes any plans the model object can provide.
  - RDF::Query now always uses a cost model (defaulting to ::Naive).
  - RDF::Query::Federate now defaults to SPARQLP parser.
  - Removed logging/warn calls from forked process in ::Service (was screwing up the parent-child IO pipe).
  - Removed use of "DISTINCT" queries in SERVICE calls (for pipelining).
  - ServiceDescription now only runs sofilter if ?subject/?object are bound.
  - Started work on a more holistic approach to supporting service descriptions (instead of using add_computed_statement_generator()).
  - Updated ::Algebra::Service to fork and use LWP's callback mechanism for concurrency.
  - ::Algebra::Service now defers loading of content until the first result is requested.
  - ::Model::RDFTrine now only produces BGP plans if there is no get_computed_statement_generators in the query object.
  - Code now materializes all node identities before creating the Bloom filter (so capacity arg is accurate).
  - Bloom filter use is now only attempted on SERVICE blocks that don't immediately contain a FILTER.
  - Re-ordered conditionals so that the service-bloom-filter try block is called less frequently.
  - SERVICE execution now uses non-identity reasoning Bloom filter function.
- Syntax and Serialization
  - Added from_sse method to ::Statement, ::Node.
  - Added initial code for ARQ-style property paths.
  - Added initial parser code for SPARQL Update (SPARUL) extension.
  - Added new 'UNSAID' syntax for SPARQLP, implementing negation.
  - Added parse_expr method to RDF::Query::Parser::SPARQL.
  - Added RDF::Query::Algebra::Quad::bf() method.
  - Fixed RDQL parser to qualify URIs before returning from parse().
  - Fixed SSE serialization of Aggregates using '*' instead of a variable as the column.
  - Removed (now unused) parser generator script.
  - SPARQL parser now always adds a ::Algebra::Project (even when the query selects '*').
  - SPARQL parser now creates ::Algebra::Construct objects for CONSTRUCT queries.
  - SPARQL parser now puts ::Distinct above ::Sort algebras in the parse tree.
  - SPARQLP parser now creates ::Project object as parent of any ::Aggregate.
  - Turtle parser now doesn't modify the lexical value of numeric typed literals.
  - Turtle parser now makes universal IDs for all blank node (even those with given IDs like _:xyz).
  - Updated ::Algebra SSE serializations to conform to Jena's serialization syntax.
  - Updated ::Algebra::Limit::sse to emit 'slice' serialization if its child is a ::Algebra::Offset.
  - Updated as_sparql() methods to support the new ::Construct classes.
  - Updated RDF::Query::sse to emit base and prefix serializations.
  - Updated SPARQL parser and serializer tests to always assume an ::Algebra::Project on SELECT queries.
  - Updated SSE serialization of ::Join::PushDownNestedLoop to use 'bind-join' terminology.
  - Updates to SPARQLP parser to support FeDeRate BINDINGS keyword.
  - ::Algebra::Distinct now does proper serialization in as_sparql().
  - ::GroupGraphPattern::sse() updated to output the '(join ...)' only if the GGP has more than one pattern.
- Optimizer
  - Added benchmark/plans.pl to show the runtimes of the available QEPs for a query.
  - Added benchmark/costmodel.pl for testing the RDF::Query::CostModel.
  - Added logging for execution time (time to construct iterator) of Triples, BGPs, GGPs and sorting.
  - Added logging of cardinalities in ::Algebra::Triple, ::Algebra::BasicGraphPattern and ::Algebra::Service.
  - Added logging to plan classes ::NestedLoop, ::Service, ::Triple.
  - Naive plan is used in ::Federate::Plan::generate_plans only if no optimistic plans are available.
  - Updated cost model code to work with ::Plan classes instead of ::Algebra classes.
  - Logging code now uses sse serialization as log keys (because of expressions that can't be serialized as SPARQL).
  - Logging object can now be passed to RDF::Query constructor.
  - Updated logging of algebra execution to use SPARQL serialization as logging key.
- Miscellaneous
  - SPARQL parser now constructs ::Algebra::Project objects (had been in RDF::Query::execute).
  - Updated RDF::Query to require version 0.108 of RDF::Trine.
  - Added new bloom:filter function variant that doesn't use identity reasoning.
  - Added debugging information when RDFQUERY_THROW_ON_SERVICE is in effect.
  - Fixed test plan for t/optimizer.t in cases where no appropriate model is available.
  - Updated plan generation code to use ::BGPOptimizer when the model supports node_counts.
  - Fixed SSE serialization bug in ::Algebra::Sort.
  - Fixed bugs in RDF::Query and RDF::Query::Expression classes that insisted variables be RDF::Query objects (and not simply RDF::Trine objects).
  - Fixed propogation of iterator binding_names when pre-bound values are used in ::Algebra execution.
  - Fixed RDF::Query::Algebra::Triple to correctly set binding_names when pre-binding is used.
  - Fixed use of pre-binding in execution of RDF::Trine optimized BasicGraphPatterns.
  - Fixed bug in SQL compilation when restricting left-joins to specific node types (based on functions like isIRI).
  - Fixed node identity computation based on owl:sameAs.
  - Fixed bitrotted livejournal example script to work with new 2.000 API.
- Tests
  - Added expected result count test in t/34-servicedescription.t.
  - Added initial tests for algebra subsumes method.
  - Added logging and costmodel tests.
  - Added more example capabilities and patterns to the test service descriptions.
  - Added RDF::Trine::Store::Hexastore to test model construction list in t/models.pl.
  - Added sparql:pattern data to test service descriptions.
  - Added sse re-serialization test to t/29-serialize.t.
  - Added support for sparql:pattern in service description parsing.
  - Added t/plan-rdftrine.t to test QEP generation optimized for RDF::Trine BGPs.
  - Added test data for repeat patterns (e.g. { ?a ?a ?b}).
  - Added tests to t/plan.t for QEP sse serialization.
  - Cleaned up federation tests.
  - Commented out in-progress service description tests.
  - Fixed bug in t/23-model_bridge.t to allow two models from the same model class to be used in testing.
  - Fixed error handling in t/plan.t.
  - Fixed t/costmodel-naive.t to provide a serialized query to ::Plan::Service constructor.
  - Fixed test count in algebra-bgp.t.
  - Fixed test in t/31-service.t that relied on identity-reasoning support in bloom filters (which is now off by default).
  - Fixed use of RDFQUERY_NETWORK_TESTS in 31-service.t.
  - Improved use of temporary RDF::Trine stores in RDF::Query tests.
  - Marked tests TODO for federated query serialization.
  - Removed what looks like an accidentally pasted test in t/plan.t.
  - SERVICE tests involving bloom filter handling marked as TODO.
  - ServiceDescription parsing now gets entire sparql:patterns and not just arcs to depth one.
  - Silenced unfinished test debugging in t/logging.t.
  - Updated args to roqet call in failing_earl_tests.sh.
  - Updated costmodel and logging test expected results that changed due to changes to ::Plan::Join code.
  - Updated dawg-eval.t regex to recognize RDFTrine blank nodes.
  - Updated DBPedia test query in t/34-servicedescription.t to reflect new source data.
  - Updated expected cardinalities in t/logging.t for current plan choice.
  - Updated logging tests to use the new sparql serialization keys.
  - Updated SERVICE test in t/plan.t (still broken, but only runs when dev env var RDFQUERY_NETWORK_TESTS in effect).
  - Updated t/plan.t to be less dependent on the specific state of the kasei.us service endpoint.
  - Updated test service description RDF for new tests.
  - Updates to improve logging and test coverage.
- Examples and Documentation
  - Added examples/query.pl to show a simple example of loading data and executing a query.
  - Added examples/create_query_api.pl for generating queries programatically (based on request from KjetilK).
  - Added bin/graph-bgp.pl to produce a png of a query's BGP variable connectivity graph.
  - Added bin/graph-query.pl to graph the (one chosen) QEP tree.
  - Added bin/graph-qeps.pl to vizualize all QEPs of a query with GraphViz.
  - Updated bin/parse.pl to emit the SSE serialization of the query algebra tree.
  - Updated bin/rdf_parse_turtle.pl to warn on any parser error.

### Version 2.002 (2008-04-25)

- Updated Bloom::Filter required version in RDF-Query's Makefile.PL.
- Fixed bug in get_function() when called as a class method.
- Updated sparql:logical-* functions to accept more than two operands.
- Added code to make loading of Bloom::Filter optional.
- Added Bloom::Filter to list of recommended modules.

### Version 2.001 (2008-04-19)

- Fixed use of "DESCRIBE <resource>" (instead of "DESCRIBE ?var").
- Fixed SPARQL serialization of queries with DISTINCT.
- Added ::Algebra::subpatterns_of_type method for retrieving all subpatterns of a particular type.
- Moved sort_rows() into new ::Algebra classes Sort, Limit, Offset and Distinct.
- Updated SQL compiler to handle new ::Algebra classes.
- Bumped required RDF::Trine version to 0.106.
- Added methods to RDF::Query for retrieving lists of supported SPARQL extensions and extension functions.
- RDF::Trine pattern optimization now holds onto the original BGP object for forwarding of calls to as_sparql().
- Removed use of Storable module. Query execution no longer clones parse tree before running.
- Simplified project operation on query stream in RDF::Query::execute().
- fixup() method in ::Algebra and ::Expression now passed the query object as an argument.
- Replaced ::RDFTrine::unify_bgp with more general fixup() implementation.
- ::Algebra classes now defer to the bridge during fixup() to allow model-specific optimizations.
- RDF::Trine::Iterator::smap now allows overriding default construct_args (e.g. binding names).
- sparql:str now throws a TypeError if argument isn't bound.
- Fixed referenced_variables in RDF::Query::Expression.
- Fixed COUNT function to only count bound variables.
- Fixed aggregation to work with expressions.
- Added support for GROUP BY clauses to aggregation queries.
- Removed now unused ::Algebra::OldFilter class.
- Added serialization tests for aggregate and union patterns.
- Moved as_sparql methods from RDF::Trine:: to RDF::Query:: classes.
- Removed context- (quad-) specific code from RDF::Query::Algebra::Triple.
- Fixed serialization of BOUND filter functions.
- Fixed serialization of unary expressions.
- Fixed call to join_streams to use ::Iterator::Bindings instead of ::Iterator.
- var_or_expr_value now takes bridge object as an argument.
- var_or_expr_value will now accept any RDF::Query::Expression object as an argument.
- Added test for using AS syntax for variable renaming: "(?var AS ?newvar)".
- Added support for MIN, MAX, COUNT and COUNT-DISTINCT aggregate operators to the SPARQLP parser.
- Added COUNT DISTINCT variant aggregate operator.
- Aggregates (MIN, MAX, COUNT, COUNT-DISTINCT) now return xsd:decimal values (this shouldn't really happen for non-numeric operands to MIN and MAX...)
- Added as_sparql submethod to RDF::Query::Node::Literal to serialize numeric types unquoted.
- Added var_or_expr_value method in RDF::Query.
- Removed unused _true and _false methods in RDF::Query.
- Fixed existing aggregates code and tests.
- Removed unused (and bitrotted) t/05-stress.t test.
- Made all tests that access the network opt-in with the RDFQUERY_NETWORK_TESTS environment variable.
- Updated POD for ::Expression::Alias.
- Added tests for select expressions.
- Added initial support for selecting expression values.

### Version 2.000 (2008-03-19)

- RDF::Query now uses RDF::Trine package for common classes (nodes, statements, iterators).
- Moved RDF::Query::Stream into RDF::Trine::Iterator namespace.
- Reshuffled SPARQL parsers tests.
- Added support for RDF::Trine::Model.
- RDF::Trine::Iterator can serialize to XML and JSON natively; Updated tests accordingly.
- rdf namespace is only added by default for RDQL.
- Fixed bug where the wrong bridge object would be returned for queries with FROM clauses.
- Moved query_more code to Algebra classes.
- Added RDF::Query::pattern method to return the GGP algebra pattern for the query.
- Added RDF::Query::as_sparql method to serialize query as SPARQL string.
- Removed unused RDF::Query::set_named_graph_query method.
- Fixed bug where triples from a FROM clause were loaded into the underlying persistent store.
- Added POD to RDF::Query::Node classes.
- Added equal method to RDF::Query::Node classes.
- RDF::Query::Node::Blank constructor now optionally produces identifiers.
- Merged tSPARQL parsing code into new SPARQLP parser.
- Added definite_variables method to RDF::Query::Algebra classes.
- Triple class now serializes rdf:type shortcut 'a' appropriately.
- Removed 'VAR' type from ::Node::Variable object structure.
- Updated code to always expect a HASH reference from ::Bindings iterator.
- Added more (sparql and see) serialization tests.
- Removed old fixup code, replaced by ::Algebra fixup methods.
- Moved FROM clause data loading to its own method.
- Started removing old code (RDF::Base, direct DBI use, AUTOLOAD, profiling).
- Moved general count_statements() method into bridge superclass.
- Fixed SQL compiler to work with ::Algebra and ::Node classes.
- Added as_native method to bridge superclass for converting ::Node objects to bridge-native objects.
- Updated document namespace declaration for SPARQL XML Results.
- Added support for SERVICE queries (ala ARQ) with Bloom filter semijoins.
- Moved Expression classes out of the Algebra hierarchy and into their own space (RDF::Query::Expression).

### Version 1.501 (2007-11-15)

- Fixed CONSTRUCT+OPTIONAL bug.
- Added as_sparql methods to Algebra and Node classes to serialize patterns in SPARQL syntax.
- Added deparse script.
- Fixed jena:sha1sum tests when Digest::SHA1 isn't available.

### Version 1.500 (2007-11-13)

- Query Engine
  - URIs are now properly qualified with a BASE when present.
  - Base URI passed to constructor is now used if no BASE clause exists in the query.
  - Fixed BASE qualification when an IRI contains Unicode characters (Emulating IRI support with the URI module).
  - NAMED graph data is now seperated from the default model into new (temporary) models.
  - NAMED graphs now work with RDF::Core.
  - Added new RDF::Query::Algebra:: classes that are used to represent query ASTs.
  - Added new RDF::Query::Node:: classes that are used to represent RDF Nodes and Variables.
  - Major refactoring to RDF::Query::query_more() to enhance extensibility.
  - Added RDF::Query::query_more_triple() and RDF::Query::query_more_bgp() for triple and bgp matching.
  - Improved support of GGP pattern matching.
  - Added sgrep, smap, swatch and concat methods to RDF::Query::Stream class.
  - Refactored query_more() variants and sort_rows() to use new stream methods sgrep, smap, and concat.
  - Continued to fix bugs to more closely align with DAWG tests.
  - Updated DAWG tests to run with the RDF::Core backend.
  - Any DAWG tests with mf:requires are now automatically marked TODO.
  - DAWG tests graph equality is now punted to user verification.
  - Fixed bNode merging code in DAWG tests.
  - query_more() variants and sort_rows() now all return RDF::Query::Stream objects.
  - query_more() (and everything it calls) now expects bridge object as a method argument (to ensure NAMED graph querying works).
  - Added join_streams() to perform netsted-loop natural joins on two Stream objects.
- Filters
  - Added call_function() method to abstract the generation of ['FUNCTION',...] blocks.
  - FILTER operator != is now negative for unknown datatypes.
  - Fixed exception handling in check_constraints().
  - Fixed type-promotion in arithmetic operations and added recognized xsd numeric types.
  - API Chnage: extension functions now take a bridge object as their second argument (after the query object).
  - Fixed equals() method in RDF::Core bridge to properly use the RDF::Core API.
  - Javascript function makeTerm now accepts language and datatype parameters.
  - toString() javascript funtion now returns just the literal value (not including language or datatype).
  - sop:str now will stringify blank nodes properly.
  - sparql:langmatches now properly differentiates between no language tag and an empty language tag.
- Parsers
  - Parsers now generate ASTs using the Algebra and Node classes.
  - Fixed bugs in SPARQL tokenizer for some Unicode strings (with combining accents).
  - RDF::Query::Parser::new_literal() now canonicalizes language tags (to lowercase).
  - Fixed GGP verification in RDF::Query::Parser::SPARQL::fixup().
  - Merged GGPAtom changes from tSPARQL to SPARQL grammar.
- Backends
  - Fixed bug in RDF::Query::Model::RDFCore::equals() when comparing two blank nodes.
  - Changed RDF::Query::Model::RDFCore::as_string to return strings where node type is identifiable (like Redland, URIs as [...], literal \"...\", bnodes (...)).
  - Model methods literal_value, literal_datatype and literal_value_langauge now return undef if argument isn't a literal.
  - Model methods uri_value and blank_identifier now return undef unless argument is of correct type.
  - Model add_string methods now normalize Unicode input.
  - Blank node prefix is now scoped to bridge, not lexically in RDF::Query::Model::RDFCore.
  - RDF::Query::Model::Redland::new_literal now forces argument to a string (XS code breaks on non-PVOK scalars).
  - RDF::Query::Model::Redland::add_uri now uses LWP instead of relying on Redland to fetch content.
  - Redland model class now recognizes DateTime objects as literals.
  - Updated add_uri() method in RDF::Core bridge to support named graphs (only one name per model for now).
- Miscellaneous
  - Added rudimentary profiling code (Devel::DProf seems to crash on RDF::Query)
  - Added initial code for supporting property functions (using time:inside as an example).
  - Removed multi_get code.
  - Removed code for MULTI patterns. Will replace with algebra-based optimization in the future.
  - RDF::Query::Stream constructor now accepts an ARRAY reference.
  - Stopped using the peephole optimizers. Will replace with an algebra-based optimizer in the future.

### Version 1.044 (2007-09-13)

- DAWG tests now emit EARL reports.
- Added test harness and temporal data importing scripts to new bin/ directory.
- Added support for temporal queries in RDF::Query and optimizers.
- Added support for CONSTRUCT queries in new YAPP-based SPARQL parsers.
- Added TIMED graph tests for new SPARQL temporal extensions.
- Added tests to SPARQL parser for bugs that were discovered with temporal extensions.
- Added POD to new SPARQL parsers.
- Added new Parse::Yapp-based SPARQL parser in preparation for temporal SPARQL extensions.
- Added stub functions for temporal extension support.
- Added model_as_stream() method to Redland bridge class.
- Addded debug() method to RDF::Query::Model.
- Added UNION tests.
- Added a javascript debugging flag to RDF::Query.
- Added RDF::Query::groupgraphpattern() for handling GGPs.
- Added xsd:integer casting function.
- Added <http://kasei.us/2007/09/functions/warn> as a FILTER tee that warns to STDERR.
- Added Eyapp SPARQL grammer file and replaced parser with auto-generated code from eyapp.
- Marked some SPARQL parser tests as TODO (due to incompatability with new YAPP-based parser).
- Network tests are now run against all available models.
- Stream tests are now run against all available models.
- Query parser initialization code cleaned up (and now supports beta tSPARQL parser).
- net_filter_function() now properly accesses nodes with bridge methods.
- RDF::Query::Parser::new_blank now assigns default names if none is supplied.
- Updated error messages in SPARQL parser to align with new YAPP-based parser.
- SPARQL parse_predicate_object() fixed to support tripleNodes.
- SPARQL parse_object() and parse_predicate() fixed for whitespace insensitivity.
- Moved old hand-written SPARQL parser to now unused SPARQL-RD.pm.
- Moved new YAPP-based SPARQL parser to SPARQL.pm.
- Copied YAPP-based SPARQL parser for new temporal extension tSPARQL.pm.
- Moved existing tests for hand-written SPARQL parser to 01-sparql_parser.t.rd-old.
- Moved new YAPP-based SPARQL tests to t/01-sparql_parser.t.
- Removed bad-syntax queries from optimizer and SQL compiler tests.
- Fixed bad-syntax queries in stream and hook tests.
- Made output of coverage tests easier to read by adding test names.
- Fixed SPARQL parsers to allow keywords as variable names.
- Fixed SPARQL parsers to allow dashes and underscores in variable names.
- Fixed bad parser constructor call in SQL compiler tests.
- Suppressed RDF::Base loading (again) during RDF::Query startup.
- RDF::Query::Model::Redland::debug now shows contexts during iterator debugging.
- Moved the old (hand written) SPARQL parser out of the way to make test harnesses happy.
- SPARQL parser now respects spec regarding the reuse of blank node labels across BGPs.
- SPARQL parser now does the right thing with NIL (the empty list).
- SPARQL parser now handles embedded GGPs correctly.
- Updated SPARQL parser and tests to pass (almost all) DAWG tests.
- Fixed bug where results couldn't be sorted by a non-selected variable.
- Removed the unused RDF::Query::timed_graph() method.
- RDF::Query::qualify_uri is now more liberal in what it accepts.
- Fixed xsd:boolean casting of integer values.
- RDF::Query::Parser::new_variable can now generate private variable names.
- Fixed test suite to work properly on systems without Redland.
- Disabled loading of tSPARQL parser for release.
- Removed function prototype definitions in Model base class (was causing loading problems when models are missing).

### Version 1.043 (2007-06-14)

- Fixed broken MANIFEST causing MakeMaker code to break.

### Version 1.042 (2007-06-13)

- Added support for Javascript URL-based extension functions.
- Added GPG signing support for Javascript functions.
- Added meta methods to model classes.
- Added count_statements methods to model classes.
- Added default format for stringifying query result streams.
- Added SPARQL syntax coverage tests.
- Added stream tests.
- ISIRI() now returns a sop:isIRI function IRI.
- Redland bridge add_uri strips off URI fragment from parser base URI.
- Underlying models aren't loaded if turned off by environment variables.
- Stopped using the (currently broken) multi-get code.
- Model classes aren't used if turned off by environment variable.
- Standardized node testing to is_node (replacing older isa_node).
- GPG verification failure now throws exceptions.
- GPG fingerprint handling is now whitespace insensitive.
- Removed (currently) unused multiget tests.
- Redland bridge uri_value returns undef if not called with a node.

### Version 1.041 (2006-11-26)

- Removed unwanted '+' signs on stringified bigints when running under perl 5.6.x.
- Fixed unicode errors when running under perl 5.6.x.
- Added tests for model bridge classes.
- Fixed bugs in SQL bridge class.
- RDFCore and Redland bridge classes now throw error when passed a bad model object.
- Bridge class support() method now responds to feature requests for 'temp_model'.
- Fixed bug in RDF::Query::Model::RDFCore::isa_resource returning true for blank nodes.
- Fixed code in RDF::Query::Model::::SQL::equals().
- Added partial support for new RDF::Storage::DBI storage class.
- Added support for RDF::Query:::Model::SQL models in RDF::Query bridge code.
- Removed RDF::Query::Model::SQL::* code that's now in RDF::Storage::DBI.
- Added tests for backend bridge classes (RDF::Query::Model::*).
- Added checks for which backends support XML serialization.
- Fixed naive peephole tests in cases where model supports cost-based analysis.
- Fixed bugs in tests that were relying on as_string() to act like literal_value().
- Added RDF::Base support.
- Fixed bug in fixup() that prevented running queries against multiple models.
- Added SimpleQueryPatternError exception class for future work on multi-get optimizations.
- Removed forced dependence on Digest::SHA1.
- Makefile.PL now recommends Digest::SHA1 (for jena function) and Geo::Distance (for 07-filters.t).

### Version 1.040 (2006-07-21)

- Added support for BOUND() fiters in SQL compilation.
- SQL compiler now produces valid SQL when query variable names are SQL reserved keywords.
- Moved SPARQL parser test data into YAML.
- Added YAML as a build-time prerequisite.
- Fixed SPARQL parsing bug for blank nodes as statement objects.
- Added peephole optimizer code with naive and cost-analysis strategies.
- Added add_string method to RDF::Query::Model::Redland.
- Added node_count method to RDF::Query::Model::Redland (only used for testing at this point).
- RDF::Query::execute() now uses the peephole optimizer.
- Removed punting code in RDF::Query::execute that tried to do JIT optimization.
- Removed calls to getLabel() on model objects in test files.
- Fixed dawg tests (was dying because of multiple plans being printed).
- Fixed cost-based peephole optimizer tests (by forcing Redland to do node counting).

### Version 1.039 (2006-07-14)

- Removed dawg tests from distribution. Only used as developer tests now.
- Updated package to use Module::Install instead of ExtUtils::MakeMaker.
- Fixed a spurious uninitialized warning in RDF::Query::get_bridge.

### Version 1.038 (2006-07-09)

- Fixed DBI case-sensitivity for PostgreSQL support.
- Cleaned up SQL syntax for easier debugging.
- Removed extra parens in SQL that were causing postgresql to break.
- Reference test foaf file using File::Spec->catfile() instead of directly.
- Fixed SPARQL parsing bug for anonymous nodes in FILTER expressions.
- Fixed major SQL compilation bugs for testing equality in FILTER expressions.
- Fixed bug in hashing code for blank nodes in SQL compiler.

### Version 1.037 (2006-07-06)

- execute() method now takes optional 'bind' parameter for pre-binding query variables.
- Updated code to support basic FILTERs in SQL compilation.
- Fixed bug in SQL compilation where no WHERE clause was needed.
- Fixed bug in SQL compilation when using model-specific Statements tables.
- Added Storable to the list of required modules (was missing in the list).
- Fixed typos in metadata about past versions in DOAP Changes.ttl.

### Version 1.036 (2006-06-26)

- Fixed memory leak in RDF::Query::Stream that resulted in too many database handles.
- Initial support for OPTIONALs in SQL compiler.
- Removed LWP requirement for systems without libwww.
- Added support for class variable to hold parsing errors. (Beware under threads.)
- RDF::Query now sets error variable upon parsing error. (Access with error().)
- Fixed POD errors, and added tests for POD coverage.
- Added model API methods to SQL model class.
- Added close() method to RDF::Query::Stream.

### Version 1.035 (2006-06-04)

- Added DAWG tests and harness.
- Rewrote core logic in OPTIONAL handling code.
- Comparisons on literals now respect numeric datatypes.
- Fixed outdated calling conventions in casting functions.
- Added custom functions:
  - jena:sha1sum
  - jena:now
  - jena:langeq
  - jena:listMember
  - ldodds:Distance
- Added new model methods: equals, subject, predicate, object.
- Relocated external http-based test data to .Mac URLs.

### Version 1.034 (2006-05-01)

- Added JSON serialization for bindings and boolean queries.
- Initial support for compiling RDF queries to SQL queries using the Redland schema.
- Added to_string method to query results Stream class.
- Model objects now store the query parse tree for access to data needed in serialization.
- Unquoted number and boolean literals in SPARQL are now datatyped appropriately.
- Fixed crashing bug when RDF::Query::Model::Redland::as_string was called with an undefined value.
- Fixed bug parsing queries with predicate starting with 'a' (confused with { ?subj a ?type}).
- Fixed bug parsing queries whose triple pattern ended with the optional dot.

### Version 1.033 (2006-03-08)

- Updated test suite to work if one of the model classes is missing.
- Data-typed literals are now cast appropriately when used in a FILTER.
- Added support for xsd:dateTime datatypes using the DateTime module.
- Added support for LANG(), LANGMATCHES() and DATATYPE() built-in functions.
- Updated TODO list.
- Added more exception types to RDF::Query::Error.
- Added POD coverage.
- Fixed SPARQL parsing bug for logical operators <= and >=.

### Version 1.032 (2006-03-03)

- Replaced the Parse::RecDescent SPARQL parser with a much faster hand-written one.
- Updated SPARQL parsing rules to be better about URI and QName character sets.
- FILTER equality operator now '=', not '==' (to match SPARQL spec).
- Initial support for FILTER constraints as part of the triple pattern structure (Will allow for nested FILTERs).
- Implemented support for ordering query results by an expression.
- Fixed bug in expresion handling of unary minus.
- Fixed bug in Redland NAMED GRAPH parsing.
- Fixed bug in RDF::Core parsing code where blank nodes would be accidentally smushed.

### Version 1.031 (2006-02-08)

- Added support for NAMED graphs.

### Version 1.030 (2006-01-13)

- Added support for SELECT * in SPARQL queries.
- Added support for default namespaces in SPARQL queries.
- Added tests for querying RDF collections in SPARQL (1 ?x 3)
- Added tests for triple patterns of the form { ?a ?a ?b . }
- Added tests for default namespaces in SPARQL.
- Added tests for SELECT * SPARQL queries.
- Bugfix where one of two identical triple variables would be ignored ({ ?a ?a ?b }).

### Version 1.028 (2005-11-18)

- Added SPARQL functions: BOUND, isURI, isBLANK, isLITERAL.
- Updated SPARQL REGEX syntax.
- Updated SPARQL FILTER syntax.
- Added SPARQL RDF Collections syntactic forms.
- Fixed FILTER support in OPTIONAL queries.
- Added binding_value_by_name method to Query results stream class.
- Added isa_blank methods to RDF::Redland and RDF::Core model classes.
- Fixed RDF literal datatyping when using Redland versions >= 1.00_02.
- Updated SPARQL grammar to make 'WHERE' token optional.
- Added <commit> directives to SPARQL grammar.
- Updated SPARQL 'ORDER BY' syntax to use parenthesis.
- Fixed SPARQL FILTER logical-and support for more than two operands.
- Fixed SPARQL FILTER equality operator syntax to use '=' instead of '=='.
- Now requires Test::More 0.52 because of changes to is_deeply().

### Version 1.027 (2005-07-28)

- Updated to follow SPARQL Draft 2005.07.21:
  - ORDER BY arguments now use parenthesis.
  - SPARQL parser now supports ORDER BY operands: variable, expression, or function call.
- Added binding_value_by_name() method to query result streams.

### Version 1.026 (2005-06-05)

- Added new DBI model bridge (accesses Redland's mysql storage directly).
- Added built-in SPARQL functions and operators (not connected to grammar yet).
- Added bridge methods for accessing typed literal information.

### Version 1.024 (2005-06-02)

- Added missing SPARQL OFFSET grammar rules.
- Added XML Results support for graph and boolean queries (DESCRIBE, CONSTRUCT, ASK).
- Fixed major bugs in RDF::Core bridge:
  - - Bridge wasn't using passed model.
  - - Literal construction was broken.
  - - Blank node construction was broken when no identifier was specified.
- Stream::bindings_count now returns the right number even if there is no data.
- XML Result format now works with RDF::Core models.
- The Model bridge object is now passed to the Stream constructor.
- Internal code now uses the variables method.
- Removed redundant code from ORDER BY/LIMIT/OFFSET handling.
- Removed unused count method.
- Removed unused delegating AUTOLOAD.
- Removed unused parse_files method.
- Removed usused add_file method.
- Removed duplicate net test file.
- Added test file for local file-based SPARQL 'FROM' queries.
- Added test file for SPARQL Result Forms (LIMIT, ORDER BY, OFFSET, DISTINCT).
- Added test file for SPARQL Protocol for RDF (XML Results).
- Added new tests based on Devel::Cover results.
- Some test files now run against both Redland and RDF::Core:
  - - 00-simple.t
  - - 03-coverage.t
  - - 10-sparql_protocol.t
- All debugging is now centrally located in the _debug method.
- Moved Stream class to lib/RDF/Query/Stream.pm.
- Fixed tests that broke with previous fix to CONSTRUCT queries.
- Fixed tests that broke with previous change to ASK query results.

### Version 1.021 (2005-06-01)

- Added SPARQL UNION support.
- Broke OPTIONAL handling code off into a seperate method.
- Added new debugging code to trace errors in the twisty web of closures.

### Version 1.020 (2005-05-18)

- Added support for SPARQL OPTIONAL graph patterns.
- Calling bindings_count on a stream now returns 0 with no data.
- Added Stream methods:
  - is_bindings
  - binding_name
  - binding_values
  - binding_names
- Added as_xml method to Stream class for XML Binding Results format.

### Version 1.016 (2005-05-08)

- Added initial support for SPARQL ASK, DESCRIBE and CONSTRUCT queries.
  - Added new test files for new query types.
- Added methods to bridge classes for creating statements and blank nodes.
- Added as_string method to bridge classes for getting string versions of nodes.
- Broke out triple fixup code into fixup_triple_bridge_variables().
- Updated FILTER test to use new Geo::Distance API.

### Version 1.015 (2005-05-03)

- Fixes to the arguments passed to FILTERs.
- Filter tests now show example of two custom filters:
  - Transitive subClassOf testing.
  - Logical comparison operators (range testing lat/lon values).
- Added literal_value, uri_value, and blank_identifier methods to bridges.
- Redland bridge now calls sources/arcs/targets when only one field is missing.
- Fixes to stream code. Iterators are now destroyed in a timely manner.
  - Complex queries no longer max out mysql connections under Redland.
- Cleaned up node sorting code.
  - Removed dependency on Sort::Naturally.
  - Added new node sorting function ncmp().
- check_constraints now calls ncmp() for logical comparisons.
- Added get_value method to make bridge calls and return a scalar value.
- Fixed node creation in Redland bridge.
- Moved DISTINCT handling code to occur before LIMITing.
- Added variables method to retrieve bound variable names.
- Added binding_count and get_all methods to streams.
- get_statments bridge methods now return RDF::Query::Stream objects.

### Version 1.014 (2005-04-26)

- Made FILTERs work in SPARQL.
- Added initial SPARQL support for custom function constraints.
- SPARQL variables may now begin with the '$' sigil.
- Added direction support for ORDER BY (ascending/descending).
- Added 'next', 'current', and 'end' to Stream API.

### Version 1.012 (2005-04-24)

- Stream objects now handle being constructed with an undef coderef.
- Streams are now objects usinig the Redland QueryResult API.
- RDF namespace is now always available in queries.
- row() now uses a stream when calling execute().
- Added ORDER BY support to RDQL parser.
- SPARQL constraints now properly use the 'FILTER' keyword.
- SPARQL constraints can now use '&&' as an operator.
- SPARQL namespace declaration is now optional.
- Updated tests.

### Version 1.010 (2005-04-21)

- `execute` now returns an iterator
- Added core support for DISTINCT, LIMIT, OFFSET
- Added initial core support for ORDER BY (only works on one column right now)
- Broke out the query parser into it's own RDQL class
- Added initial support for a SPARQL parser
  - Added support for blank nodes
  - Added lots of syntactic sugar (with blank nodes, multiple predicates and objects)
  - Added SPARQL support for DISTINCT and ORDER BY
- Moved model-specific code into RDF::Query::Model::*
- Moving over to redland's query API (pass in the model when query is executed)

## Copyright

Copyright © 2005–2015 Gregory Williams. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.