1Devel::Declare::Parser(U3s)er Contributed Perl DocumentatDieovnel::Declare::Parser(3)
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NAME

6       Devel::Declare::Parser - Higher level interface to Devel-Declare
7

DESCRIPTION

9       Devel-Declare-Parser is a higher-level API sitting on top of
10       Devel::Declare.  It is used by Devel::Declare::Exporter to simplify
11       exporting of Devel::Declare magic. Writing custom parsers usually only
12       requires subclassing this module and overriding a couple methods.
13

DOCUMENTATION

15       Devel::Declare::Interface
16           This is the primary interface for those who want to use Devel-
17           Declare-Parser magic, and don't want to use Exporter-Declare.
18
19       Devel::Declare::Parser
20           This Document covers the API for Devel::Declare::Parser. This API
21           is a useful reference when writing or modifying a custom parser.
22

SYNOPSIS

24           package Devel::Declare::Parser::MyParser;
25           use strict;
26           use warnings;
27
28           use base 'Devel::Declare::Parser';
29           use Devel::Declare::Interface;
30
31           # Create an accessor (See INTERNALS WARNING below)
32           __PACKAGE__->add_accessor( 'my_accessor' );
33
34           # Register the parser for use.
35           Devel::Declare::Interface::register_parser( 'myparser' );
36
37           # Override the rewrite() method to take the parsed bits (parts) and put the
38           # ones you want into new_parts.
39           sub rewrite {
40               my $self = shift;
41
42               my $parts = $self->parts;
43
44               $new_parts = $self->process_parts( $parts );
45
46               $self->new_parts( $new_parts );
47               1;
48           }
49
50           1;
51

OVERVIEW

53       This is a brief overview of how a parser is used.
54
55   WORKFLOW
56       Parser is constructed
57           Name, Declarator, and Offset are provided by Devel::Declare.
58
59       The process() method is called
60           The process method calls all of the following in sequence, if any
61           returns false, process() will return.
62
63           pre_parse()
64                   Check if we want to process the line at all.
65
66           parse() Turn the line into 'parts' (see below).
67
68           post_parse()
69                   Hook, currently does nothing.
70
71           rewrite()
72                   Hook, currently takes all the arguments between the
73                   declarator and the codeblock/semicolon (which have been
74                   turned into 'parts' structures in the parts() attribute)
75                   and puts them into the new_parts() attribute.
76
77                   This is usually the method you want to override.
78
79           write_line()
80                   Opens, fills in, and closes the line as a string, then
81                   rewrites the actual line using Devel::Declare.
82
83           edit_line()
84                   Hook, currently does nothing.
85
86   "PARTS"
87       'Parts' are datastructures created by the parse() method. Every
88       argument on the line (space separated) up until an opening curly brace
89       ({) or a semicolon (;) will be turned into a part. Here are the parts
90       to expect:
91
92       Parts will either be a plain string, or an arrayref containing a string
93       and the quote character used to define the string. "String" or [
94       "String", '"' ].  Variables and operators (excluding those containing
95       only string characters) are typically the only parts left in a plain
96       string form.
97
98       See the format_parts() method for an easy way to get what you need from
99       a 'part' datastructure.
100
101       Bareword or Package Name
102           A bareword name is anything that starts with [a-zA-z] and contains
103           only alpha-numerics plus underscore. It is also not quoted.
104           Examples include my_name, something5, etc.
105
106           The structure will be an arrayref, the first element will be the
107           string form of the bareword name, the second element will be undef.
108
109           Example:
110
111               # my_keyword My::Package;
112               $part = [
113                   'My::Package',
114                   undef,
115               ];
116
117               # my_keyword some_name;
118               $part = [
119                   "some_name",
120                   undef,
121               ];
122
123       Quoted or Enclosed Element
124           A quoted or enclosed element includes strings quoted with single or
125           double quotes, and text contained within opening and closing
126           brackets, braces or parens (excluding the curly brace '{').
127
128           Example Structures:
129
130               # my_keyword "double quoted string";
131               $part = [
132                   'double quoted string',
133                   '"',
134               ];
135
136               # my_keyword 'single quoted string';
137               $part = [
138                   'double quoted string',
139                   '"',
140               ];
141
142               # my_keyword ... ( a => 'b', c => 'd' );
143               $part = [
144                   " a => 'b', c => 'd' ",
145                   "(",
146               ];
147
148       Variable or Operator
149           Anything starting with a non-alphanumeric, non-quoting character
150           will be placed as-is (not interpolated) into a string. This catches
151           most variables and operators, the exception are alpha-numeric
152           operators such as 'eq', 'gt', 'cmp', etc. Eventually I plan to add
153           logic to catch all operators, but it appears I will have to hard-
154           code them.
155
156               # my_keyword $variable
157               $part = '$variable';
158
159               # my_keyword <=>
160               $part = '<=>';
161
162   EVENTUAL OUTPUT
163       Parser is designed such that it will transform any and all uses of your
164       keyword into proper function calls.
165
166       That is this:
167
168           function x { ... }
169
170       Will become this:
171
172           function( 'x', sub { ... });
173
174       Note Parser does not read in the entire codeblock, rather it injects a
175       statement into the start of the block that uses a callback to attach
176       the ');' to the end of the statement. This is per the documentation of
177       Devel::Declare. Reading in the entire sub is not a desirable scenario.
178

DEVEL-DECLARE-PARSER API

180   INTERNALS WARNING
181       Parser objects are blessed arrays, not hashrefs.
182
183       If you want to create a new accessor use the add_accessor() class
184       method. It will take care of assigning an unused array element to the
185       attribute, and will create a read/write accessor sub for you.
186
187           __PACKAGE__->add_accessor( 'my_accessor' );
188
189       There are many public and private methods on the parser base class.
190       Only the public methods are fully documented. Be sure to refer often to
191       the list of private methods at the end of this document, accidently
192       overriding a private method could have devastating consequences.
193
194   CLASS METHODS
195       $class->new( $name, $declarator, $offset )
196           The constructor, "DO NOT OVERRIDE THIS!"
197
198       $class->DEBUG($bool)
199           Turn debugging on/off. This will output the line after it has been
200           modified, as well as some context information.
201
202           NOTE: This has a global effect, all parsers will start debugging.
203
204   UTILITY METHODS
205       bail( @messages )
206           Like croak, dies providing you context information. Since any death
207           occurs inside the parser, carp provides useless information.
208
209       diag( @message )
210           Like carp, warns providing you context information. Since the warn
211           occurs inside the parser carp provides useless information.
212
213       end_quote($start_char)
214           Find the end-character for the provide starting quote character. As
215           in '{' returns '}' and '(' returns ')'. If there is no counter-part
216           the start character is returned: "'" returns "'".
217
218       filename()
219           Filename the rewrite is occurring against.
220
221       linenum()
222           Linenum the rewrite is occurring on.
223
224       format_part()
225           Returns the stringified form of a part datastructure. For variables
226           and operators that is just the item itself as a string. For
227           barewords or package names it is the item itself with single quotes
228           wrapped around it. For quoted items it is the string wrapped in its
229           proper quoting characters. If a second parameter is provided (and
230           true) no single quotes will be added to barewords.
231
232   ACCESSORS
233       These are the read/write accessors used by Parser. Not all of these act
234       on an array element, some will directly alter the current line.
235
236       line()
237           This will retrieve the current line from Devel-Declare. If given a
238           value, that value will be set as the current line using Devel-
239           Declare.
240
241       name()
242           Name of the declarator as provided via the parser.
243
244       declarator()
245           Name of the declarator as provided via the Devel-Declare.
246
247       original_offset()
248           Offset on the line when the parsing was started.
249
250       offset()
251           Current line offset.
252
253       parts()
254           Arrayref of parts (may be undef)
255
256       new_parts()
257           Arrayref of new parts (may be undef)
258
259       end_char()
260           Will be set to the character just after the completely parsed line
261           (usually '{' or ';')
262
263       prototype()
264           Used internally for prototype tracking.
265
266       contained()
267           True if the parser determined this was a contained call. This means
268           your keyword was followed by an opening paren, and the statement
269           ended with a closing paren and semicolon. By default Parser will
270           not modify such lines.
271
272   OVERRIDABLE METHODS
273       These are methods you can, should, or may override in your baseclass.
274
275       quote_chars()
276           Specify the starting characters for quoted strings. (returns a
277           list)
278
279       end_chars()
280           Characters to recognise as end of statement characters (';' and
281           '{') (returns a list)
282
283       inject()
284           Code to inject into functions enhanced by this parser.
285
286       pre_parse()
287           Check if we want to process the line at all.
288
289       parse()
290           Turn the line into 'parts'.
291
292       post_parse()
293           Hook, currently does nothing.
294
295       rewrite()
296           Hook, currently takes all the arguments between the declarator and
297           the codeblock/semicolon (which have been turned into 'parts'
298           structures in the parts() attribute) and puts them into the
299           new_parts() attribute.
300
301           This is usually the method you want to override.
302
303       write_line()
304           Opens, fills in, and closes the line as a string, then rewrites the
305           actual line using Devel::Declare.
306
307       edit_line()
308           Hook, currently does nothing.
309
310       open_line()
311           Usually returns '('. This is how to start a line following your
312           keyword
313
314       close_line()
315           End the line, this means either re-inserting the opening '{' on the
316           codeblock, along with any injections, or returning ');'
317
318   POSITION TRACKING
319       advance( $num_chars )
320           Advances the offset by $num_chars.
321
322       skip_declarator()
323           Skips the declarator at the start of the line.
324
325       skipspace()
326           Advances the offset past any whitespace.
327
328   LINE EXAMINATION (NON-MODIFYING)
329       These are used by pre_parse() to examine the line prior to any
330       modification.
331
332       is_contained()
333           True if the line is of the format:
334
335               keyword( ... );
336
337       is_arrow_contained()
338           True if the line is of the format:
339
340               keyword word_or_string => ( ... );
341
342       is_defenition()
343           True if the line matches the regex m/sub[\s\n]+$name/sm
344
345   PART EXAMINATION
346       These are methods that let you investigate the parts already parsed and
347       placed in the parts() attribute.
348
349       has_non_string_or_quote_parts()
350           Returns a list of parts that are not strings, quotes, or barewords.
351
352       has_string_or_quote_parts()
353           Returns a list of parts that are strings, quotes, or barewords.
354
355       has_keyword( $word )
356           Check for a keyword in the parts
357
358       has_comma()
359       has_fat_comma()
360
361   LINE EXAMINATION (MODIFYING)
362       This examines the line returning part structures and removing elements
363       from the line each time they are called.
364
365       strip_item()
366       strip_length()
367       strip_remaining_items()
368
369   LOOKING AHEAD
370       These methods help the parser determine what comes next in a line. In
371       most cases these are non-modifying.
372
373       peek_is_block()
374       peek_is_end()
375       peek_is_other()
376       peek_is_quote()
377       peek_is_word()
378       peek_item()
379       peek_item_type()
380       peek_num_chars()
381       peek_other()
382       peek_quote()
383       peek_remaining()
384       peek_word()
385
386   PRIVATE METHODS
387       Do not use these, and definitely do not override them in a subclass.
388
389       _block_end_injection()
390       _debug()
391       _edit_block_end()
392       _item_via_()
393       _linestr_offset_from_dd()
394       _move_via_()
395       _peek_is_package()
396       _peek_is_word()
397       _quoted_from_dd()
398       _scope_end()
399       _stash()
400       _unstash()
401

FENNEC PROJECT

403       This module is part of the Fennec project. See Fennec for more details.
404       Fennec is a project to develop an extendable and powerful testing
405       framework.  Together the tools that make up the Fennec framework
406       provide a potent testing environment.
407
408       The tools provided by Fennec are also useful on their own. Sometimes a
409       tool created for Fennec is useful outside the greator framework. Such
410       tools are turned into their own projects. This is one such project.
411
412       Fennec - The core framework
413         The primary Fennec project that ties them all together.
414

AUTHORS

416       Chad Granum exodist7@gmail.com
417
419       Copyright (C) 2010 Chad Granum
420
421       Devel-Declare-Parser is free software; Standard perl licence.
422
423       Devel-Declare-Parser is distributed in the hope that it will be useful,
424       but WITHOUT ANY WARRANTY; without even the implied warranty of
425       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the license
426       for more details.
427
428
429
430perl v5.30.1                      2020-01-29         Devel::Declare::Parser(3)
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