1Pegex::Grammar(3) User Contributed Perl Documentation Pegex::Grammar(3)
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6 Pegex::Grammar - Pegex Grammar Base Class
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9 Define a Pegex grammar (for the Foo syntax):
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11 package Pegex::Foo::Grammar;
12 use base 'Pegex::Base';
13 extends 'Pegex::Grammar';
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15 has text => q{
16 foo: bar baz
17 ... rest of Foo grammar ...
18 };
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20 then use it to parse some Foo:
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22 use Pegex::Parser;
23 my $parse_tree = Pegex::Parser->new(
24 grammar => 'Pegex::Foo::Grammar',
25 receiver => 'Pegex::Tree',
26 )->parse('my/file.foo');
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29 Pegex::Grammar is a base class for defining your own Pegex grammar
30 classes. You just need to provide the grammar view the "text" or the
31 "file" attributes.
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33 When Pegex::Parser uses your grammar, it will want it in the tree
34 (compiled) form, so Pegex::Grammar provides automatic compilation
35 support.
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38 tree
39 This is the data structure containing the compiled grammar for your
40 syntax. It is usually produced by "Pegex::Compiler". You can inline
41 it in the "tree" method, or else the "make_tree" method will be
42 called to produce it.
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44 The "make_tree" method will call on Pegex::Compiler to compile the
45 "text" property by default. You can define your own "make_tree"
46 method to do override this behavior.
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48 Often times you will want to generate your own Pegex::Grammar
49 subclasses in an automated fashion. The Pegex and TestML modules do
50 this to be performant. This also allows you to keep your grammar
51 text in a separate file, and often in a separate repository, so it
52 can be shared by multiple programming language's module
53 implementations.
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55 See <https://github.com/ingydotnet/pegex-pgx> and
56 <https://github.com/ingydotnet/pegex-pm/blob/master/lib/Pegex/Pegex/Grammar.pm>.
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58 text
59 This is simply the text of your grammar, if you define this, you
60 should (probably) not define the "tree" property. This grammar text
61 will be automatically compiled when the "tree" is required.
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63 file
64 This is the file where your Pegex grammar lives. It is usually used
65 when you are making a Pegex module. The path is relative to your
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68 make_tree
69 This method is called when the grammar needs the compiled version.
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72 Ingy döt Net <ingy@cpan.org>
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75 Copyright 2010-2018. Ingy döt Net.
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77 This program is free software; you can redistribute it and/or modify it
78 under the same terms as Perl itself.
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80 See <http://www.perl.com/perl/misc/Artistic.html>
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84perl v5.28.0 2018-11-12 Pegex::Grammar(3)