1Pegex::Receiver(3)    User Contributed Perl Documentation   Pegex::Receiver(3)
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4

NAME

6       Pegex::Receiver - Base Class for All Pegex Receivers
7

SYNOPSIS

9           package MyReceiver;
10           use base 'Pegex::Receiver';
11
12           # Handle data for a specific rule
13           sub got_somerulename {
14               my ($self, $got) = @_;
15               # ... process ...
16               return $result;
17           }
18
19           # Handle data for any other rule
20           sub gotrule {
21               my ($self, $got) = @_;
22               return $result;
23           }
24
25           # Pre-process
26           sub initial { ... }
27
28           # Post-process
29           sub final {
30               ...;
31               return $final_result;
32           }
33

DESCRIPTION

35       In Pegex, a receiver is the class object that a parser passes captured
36       data to when a rule in a grammar matches a part of an input stream. A
37       receiver provides action methods to turn parsed data into what the
38       parser is intended to do.
39
40       This is the base class of all Pegex receiver classes.
41
42       It doesn't do much of anything, which is the correct thing to do. If
43       you use this class as your receiver if won't do any extra work. See
44       Pegex::Tree for a receiver base class that will help organize your
45       matches by default.
46
47   How A Receiver Works
48       A Pegex grammar is made up of named-rules, regexes, and groups. When a
49       regex matches, the parser makes array of its capture strings. When a
50       group matches, the parser makes an array of all the submatch arrays. In
51       this way a parse tree forms.
52
53       When a named-rule matches, an action method is called in the receiver
54       class. The method is passed the current parse tree and returns what
55       parser will consider the new parse tree.
56
57       This makes for a very elegant and understandable API.
58

API

60       This section documents the methods that you can include in receiver
61       subclass.
62
63       "got_$rulename($got)"
64           An action method for a specific, named rule.
65
66               sub got_rule42 {
67                   my ($self, $got) = @_;
68                   ...
69                   return $result;
70               }
71
72           The $got value that is passed in is the current value of the parse
73           tree.  What gets returned is whatever you want to new value to be.
74
75       "gotrule($got)"
76           The action method for a named rule that does not have a specific
77           action method.
78
79       "initial()"
80           Called at the beginning of a parse operation, before the parsing
81           begins.
82
83       "final($got)"
84           Called at the end of a parse operation. Whatever this action
85           returns, will be the result of the parse.
86
87   Methods
88       "parser"
89           An attribute containing the parser object that is currently
90           running. This can be very useful to introspect what is happening,
91           and possibly modify the grammar on the fly. (Experts only!)
92
93       "flatten($array)"
94           A utility method that can turn an array of arrays into a single
95           array.  For example:
96
97               $self->flatten([1, [2, [3, 4], 5], 6]);
98               # produces [1, 2, 3, 4, 5, 6]
99
100           Hashes are left unchanged. The array is modified in place, but is
101           also the return value.
102

AUTHOR

104       Ingy döt Net <ingy@cpan.org>
105

107       Copyright 2010-2020. Ingy döt Net.
108
109       This program is free software; you can redistribute it and/or modify it
110       under the same terms as Perl itself.
111
112       See <http://www.perl.com/perl/misc/Artistic.html>
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116perl v5.30.1                      2020-02-17                Pegex::Receiver(3)
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