NAME

Text::Query::Build - Base class for query builders

SYNOPSIS

    package Text::Query::BuildMy;
    use Text::Query::Build;
    
    use vars qw(@ISA);
    @ISA = qw(Text::Query::Build);

DESCRIPTION

This module provides a virtual base class for query builders.

Query builders are called by the parser logic. A given set of functions is provided by the builder to match a Boolean logic. All the methods return a scalar corresponding to the code that performs the specified options.

Parameters Q1 and Q2 are the same type of scalar as the return values.

METHODS

matchstring(): Return a string that represent the last built expression. Two identical expressions should generate the same string. This is for testing purpose.

CODE-GENERATION METHODS

build_init(): Called before building the expression. A chance to initialize object data.
build_final_expression(Q1): Does any final processing to generate code to match a top-level expression. The return value is NOT necessarily of a type that can be passed to the other code-generation methods.
build_expression(Q1,Q2): Generate code to match "Q1" OR "Q2"
build_expression_finish(Q1): Generate any code needed to enclose an expression.
build_conj(Q1,Q2,F): Generate code needed to match "Q1" AND "Q2". F will be true if this is the first time this method is called in a sequence of several conjunctions.
build_near(Q1,Q2): Generate code needed to match "Q1" NEAR "Q2".
build_concat(Q1,Q2): Generate code needed to match "Q1" immediately followed by "Q2".
build_negation(Q1): Generate code needed to match NOT "Q1".
build_literal(Q1): Generate code to match "Q1" as a literal.
build_scope_start($scope): Generate code to enter in the $scope query context.
build_scope_end($scope,Q1): Generate code needed to match "Q1" in the $scope context.
build_mandatory(Q1): Generate code to match "Q1" (think + in AltaVista syntax).
build_forbiden(Q1): Generate code to match NOT "Q1" (think - in AltaVista syntax).

AUTHORS

Eric Bohlman (ebohlman@netcom.com)