TITLE ^

PGE::Util - utility PGE subroutines

DESCRIPTION ^

The subroutines and items in this module are provided to make working with PGE a little easier.

This module defines the "PGE::P6Grammar" compiler, which can be used to compile complete sets of rules (grammars). Input to the grammar compiler is a string containing statements of the form

    grammar <name> ;
    rule <ident> { <p6rule> } ;
    # comment

A grammar statement indicates where to load any subsequent rules. Unlike Perl 6, there can be multiple grammar statements in the string.

Here's a code snippet to load a set of rules using the grammar compiler:

    load_bytecode "PGE.pbc"
    load_bytecode "PGE/Util.pir"

    $S0 = <<'END'
        grammar PGE::Rule;
        rule ident { [ _ | <?alpha> ] \w* }
        rule name { <ident> [ \:\: <ident> ]* }
    END
    $P0 = compreg "PGE::P6Grammar"
    $P1 = $P0($S0)
    # rules <PGE::Rule::ident> and <PGE::Rule::name> have now been loaded

The return value from the compiler is a string containing the PIR generated from the rules in the grammar, which can be saved and used to generate precompiled .pbc files for other packages.

Functions ^

__onload()

Generates the grammar parse rule needed to parse grammar strings.

compile_rules(STR src)

Compiles and loads a sequence of rule statements from the string given by src.


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