NAME

Text::Query - Query processing framework

SYNOPSIS

    use Text::Query;
    
    # Constructor
    $query = Text::Query->new([QSTRING] [OPTIONS]);

    # Methods
    $query->prepare(QSTRING [OPTIONS]);
    $query->match([TARGET]);
    $query->matchscalar([TARGET]);

DESCRIPTION

This module provides an object that matches a data source against a query expression.

Query expressions are compiled into an internal form when a new object is created or the prepare method is called; they are not recompiled on each match.

The class provided by this module uses four packages to process the query. The query parser parses the question and calls a query expression builder (internal form of the question). The optimizer is then called to reduce the complexity of the expression. The solver applies the expression on a data source.

The following parsers are provided:

Text::Query::ParseAdvanced
Text::Query::ParseSimple

The following builders are provided:

Text::Query::BuildAdvancedString
Text::Query::BuildSimpleString

The following solver is provided:

Text::Query::SolveSimpleString
Text::Query::SolveAdvancedString

EXAMPLES

  use Text::Query;
  my $q=new Text::Query('hello and world',
                        -parse => 'Text::Query::ParseAdvanced',
                        -solve => 'Text::Query::SolveAdvancedString',
                        -build => 'Text::Query::BuildAdvancedString');
  die "bad query expression" if not defined $q;
  print if $q->match;
  ...
  $q->prepare('goodbye or adios or ta ta',
              -litspace => 1,
              -case => 1);
  #requires single space between the two ta's
  if($q->match($line)) {
  #doesn't match "Goodbye"
  ...
  $q->prepare('"and" or "or"');
  #quoting operators for literal match
  ...
  $q->prepare('\\bintegrate\\b', -regexp => 1);
  #won't match "disintegrated"

CONSTRUCTOR

new ([QSTRING] [OPTIONS])

This is the constructor for a new Text::Query object. If a QSTRING is given it will be compiled to internal form.

OPTIONS are passed in a hash like fashion, using key and value pairs. Possible options are:

-parse - Package name of the parser. Default is Text::Query::ParseSimple.

-build - Package name of the builder. Default is Text::Query::Build.

-optimize - Package name of the optimizer. Default is Text::Query::Optimize.

-solve - Package name of the solver. Default is Text::Query::Solve.

-mode - Name of predefined group of packages to use. Options are currently simple_text and advanced_text.

These options are handled by the configure method.

All other options are passed to the parser prepare function. See the corresponding manual pages for a description.

If QSTRING is undefined, the prepare function is not called.

The constructor will croak if a QSTRING was supplied and had illegal syntax.

METHODS

configure ([OPTIONS])

Set the parse, build, optimize or solve packages. See the CONSTRUCTOR description for explanations.

prepare (QSTRING [OPTIONS])

Compiles the query expression in QSTRING to internal form and sets any options (same as in the constructor). prepare may be used to change the query expression and options for an existing query object. If OPTIONS are omitted, any options set by a previous call to prepare are persistent.

The optimizer (-optimize) is called with the result of the parser (-parse). The parser uses the builder (-build) to construct the internal form.

This method returns a reference to the query object if the syntax of the expression was legal, or croak if not.

match ([TARGET])

Calls the match method of the solver (-solve).

matchscalar ([TARGET])

Calls the matchscalar method of the solver (-solve).

AUTHORS

Eric Bohlman (ebohlman@netcom.com)

Loic Dachary (loic@senga.org)