NAME

Text::Query::Parse - Base class for query parsers

SYNOPSIS

    package Text::Query::ParseThisSyntax;
    use Text::Query::Parse;
    
    use vars qw(@ISA);
    @ISA = qw(Text::Query::Parse);

This module provides a virtual base class for query parsers.

It defines the "prepare" method that is called by the "Text::Query" object to compile the query string.

-build Pointer to a Text::Query::Build object.
scope Scope stack. Defines the context in which the query must be solved.
token The current token. Destroyed by "prepare".
tokens A reference to the list of all the tokens. Filled by parse_tokens. Destroyed by "prepare".
parseopts A reference to a hash table containing all the parameters given to the "prepare" function.
-verbose Integer indicating the desired verbose level.

prepare (QSTRING [OPTIONS]): Compiles the query expression in "QSTRING" to internal form and sets any options. First calls "build_init" to reset the builder and destroy the "token" and "tokens" members. Then calls "parse_tokens" to fill the "tokens" member. Then calls "expression" to use the tokens from "tokens". The "expression" is expected to call the "build_*" functions to build the compiled expression. At last calls "build_final_expression" with the result of "expression".
A derived parser must redefine this function to define default values for specific options.
expression (): Must be redefined by derived package. Returns the internal form of the question built from "build_*" functions using the "tokens".
parse_tokens (QSTRING): Must be redefined by derived package. Parses the "QSTRING" scalar and fills the "tokens" member with lexical units.
build_*: Shortcuts to the corresponding function of the Text::Query::Build object found in the "-build" member.

These are the options of the "prepare" method and the constructor.

-quotes defaults to \'\": Defines the quote characters.
-case defaults to 0: If true, do case-sensitive match.
-litspace defaults to 0: If true, match spaces (except between operators) in "QSTRING" literally. If false, match spaces as "\s+".
-regexp defaults to 0: If true, treat patterns in "QSTRING" as regular expressions rather than literal text.
-whole defaults to 0: If true, match whole words only, not substrings of words.

Eric Bohlman (ebohlman@netcom.com)

Loic Dachary (loic@senga.org)