YAPE::Regex(3pm)

1Regex(3)              User Contributed Perl Documentation             Regex(3)
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NAME

6       YAPE::Regex - Yet Another Parser/Extractor for Regular Expressions
7

VERSION

9       This document refers to YAPE::Regex version 4.00.
10

SYNOPSIS

12         use YAPE::Regex;
13         use strict;
14
15         my $regex = qr/reg(ular\s+)?exp?(ression)?/i;
16         my $parser = YAPE::Regex->new($regex);
17
18         # here is the tokenizing part
19         while (my $chunk = $parser->next) {
20           # ...
21         }
22

"YAPE" MODULES

24       The "YAPE" hierarchy of modules is an attempt at a unified means of
25       parsing and extracting content.  It attempts to maintain a generic
26       interface, to promote simplicity and reusability.  The API is powerful,
27       yet simple.  The modules do tokenization (which can be intercepted) and
28       build trees, so that extraction of specific nodes is doable.
29

DESCRIPTION

31       This module is yet another (?) parser and tree-builder for Perl regular
32       expressions.  It builds a tree out of a regex, but at the moment, the
33       extent of the extraction tool for the tree is quite limited (see
34       "Extracting Sections").  However, the tree can be useful to extension
35       modules.
36

USAGE

38       In addition to the base class, "YAPE::Regex", there is the auxiliary
39       class "YAPE::Regex::Element" (common to all "YAPE" base classes) that
40       holds the individual nodes' classes.  There is documentation for the
41       node classes in that module's documentation.
42
43   Methods for "YAPE::Regex"
44       •   "use YAPE::Regex;"
45
46       •   "use YAPE::Regex qw( MyExt::Mod );"
47
48           If supplied no arguments, the module is loaded normally, and the
49           node classes are given the proper inheritence (from
50           "YAPE::Regex::Element").  If you supply a module (or list of
51           modules), "import" will automatically include them (if needed) and
52           set up their node classes with the proper inheritence -- that is,
53           it will append "YAPE::Regex" to @MyExt::Mod::ISA, and
54           "YAPE::Regex::xxx" to each node class's @ISA (where "xxx" is the
55           name of the specific node class).
56
57             package MyExt::Mod;
58             use YAPE::Regex 'MyExt::Mod';
59
60             # does the work of:
61             # @MyExt::Mod::ISA = 'YAPE::Regex'
62             # @MyExt::Mod::text::ISA = 'YAPE::Regex::text'
63             # ...
64
65       •   "my $p = YAPE::Regex->new($REx);"
66
67           Creates a "YAPE::Regex" object, using the contents of $REx as a
68           regular expression.  The "new" method will attempt to convert $REx
69           to a compiled regex (using "qr//") if $REx isn't already one.  If
70           there is an error in the regex, this will fail, but the parser will
71           pretend it was ok.  It will then report the bad token when it gets
72           to it, in the course of parsing.
73
74       •   "my $text = $p->chunk($len);"
75
76           Returns the next $len characters in the input string; $len defaults
77           to 30 characters.  This is useful for figuring out why a parsing
78           error occurs.
79
80       •   "my $done = $p->done;"
81
82           Returns true if the parser is done with the input string, and false
83           otherwise.
84
85       •   "my $errstr = $p->error;"
86
87           Returns the parser error message.
88
89       •   "my $backref = $p->extract;"
90
91           Returns a code reference that returns the next back-reference in
92           the regex.  For more information on enhancements in upcoming
93           versions of this module, check "Extracting Sections".
94
95       •   "my $node = $p->display(...);"
96
97           Returns a string representation of the entire content.  It calls
98           the "parse" method in case there is more data that has not yet been
99           parsed.  This calls the "fullstring" method on the root nodes.
100           Check the "YAPE::Regex::Element" docs on the arguments to
101           "fullstring".
102
103       •   "my $node = $p->next;"
104
105           Returns the next token, or "undef" if there is no valid token.
106           There will be an error message (accessible with the "error" method)
107           if there was a problem in the parsing.
108
109       •   "my $node = $p->parse;"
110
111           Calls "next" until all the data has been parsed.
112
113       •   "my $node = $p->root;"
114
115           Returns the root node of the tree structure.
116
117       •   "my $state = $p->state;"
118
119           Returns the current state of the parser.  It is one of the
120           following values: "alt", "anchor", "any", "backref", capture(N),
121           "Cchar", "class", "close", "code", "comment", cond(TYPE), "ctrl",
122           "cut", "done", "error", "flags", "group", "hex", "later",
123           lookahead(neg|pos), lookbehind(neg|pos), "macro", "named", "oct",
124           "slash", "text", and "utf8hex".
125
126           For capture(N), N will be the number the captured pattern
127           represents.
128
129           For cond(TYPE), TYPE will either be a number representing the back-
130           reference that the conditional depends on, or the string "assert".
131
132           For "lookahead" and "lookbehind", one of "neg" and "pos" will be
133           there, depending on the type of assertion.
134
135       •   "my $node = $p->top;"
136
137           Synonymous to "root".
138
139   Extracting Sections
140       While extraction of nodes is the goal of the "YAPE" modules, the author
141       is at a loss for words as to what needs to be extracted from a regex.
142       At the current time, all the "extract" method does is allow you access
143       to the regex's set of back-references:
144
145         my $extor = $parser->extract;
146         while (my $backref = $extor->()) {
147           # ...
148         }
149
150       "japhy" is very open to suggestions as to the approach to node
151       extraction (in how the API should look, in addition to what should be
152       proffered).  Preliminary ideas include extraction keywords like the
153       output of -Dr (or the "re" module's "debug" option).
154

EXTENSIONS

156       •   "YAPE::Regex::Explain"
157
158           Presents an explanation of a regular expression, node by node.
159
160       •   "YAPE::Regex::Reverse" (Not released)
161
162           Reverses the nodes of a regular expression.
163

TO DO

165       This is a listing of things to add to future versions of this module.
166
167   API
168       •   Create a robust "extract" method
169
170           Open to suggestions.
171

BUGS

173       Following is a list of known or reported bugs.
174
175   Pending
176       •   "use charnames ':full'"
177
178           To understand "\N{...}" properly, you must be using 5.6.0 or
179           higher.  However, the parser only knows how to resolve full names
180           (those made using use charnames ':full').  There might be an option
181           in the future to specify a class name.
182

AUTHOR

189       The original author is Jeff "japhy" Pinyan (CPAN ID: PINYAN).
190
191       Gene Sullivan (gsullivan@cpan.org) is a co-maintainer.
192

LICENSE

194       This module is free software; you can redistribute it and/or modify it
195       under the same terms as Perl itself.  See perlartistic.
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199perl v5.36.0                      2023-01-20                          Regex(3)