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1 | package Function::Parameters; |
2 | |
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3 | use v5.14.0; |
4 | |
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5 | use strict; |
6 | use warnings; |
7 | |
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8 | use XSLoader; |
9 | BEGIN { |
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10 | our $VERSION = '0.05_03'; |
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11 | XSLoader::load; |
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12 | } |
13 | |
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14 | use Carp qw(confess); |
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15 | |
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16 | sub _assert_valid_identifier { |
17 | my ($name, $with_dollar) = @_; |
18 | my $bonus = $with_dollar ? '\$' : ''; |
19 | $name =~ /^${bonus}[^\W\d]\w*\z/ |
20 | or confess qq{"$name" doesn't look like a valid identifier}; |
21 | } |
22 | |
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23 | sub _assert_valid_attributes { |
24 | my ($attrs) = @_; |
25 | $attrs =~ /^\s*:\s*[^\W\d]\w*\s*(?:(?:\s|:\s*)[^\W\d]\w*\s*)*(?:\(|\z)/ |
26 | or confess qq{"$attrs" doesn't look like valid attributes}; |
27 | } |
28 | |
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29 | my @bare_arms = qw(function method); |
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30 | my %type_map = ( |
31 | function => { name => 'optional' }, |
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32 | method => { |
33 | name => 'optional', |
34 | shift => '$self', |
35 | attrs => ':method', |
36 | }, |
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37 | ); |
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38 | |
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39 | sub import { |
40 | my $class = shift; |
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41 | |
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42 | @_ or @_ = { |
43 | fun => 'function', |
44 | method => 'method', |
45 | }; |
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46 | if (@_ == 1 && ref($_[0]) eq 'HASH') { |
47 | @_ = map [$_, $_[0]{$_}], keys %{$_[0]} |
48 | or return; |
49 | } |
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50 | |
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51 | my %spec; |
52 | |
53 | my $bare = 0; |
54 | for my $proto (@_) { |
55 | my $item = ref $proto |
56 | ? $proto |
57 | : [$proto, $bare_arms[$bare++] || confess(qq{Don't know what to do with "$proto"})] |
58 | ; |
59 | my ($name, $type) = @$item; |
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60 | _assert_valid_identifier $name; |
61 | |
62 | unless (ref $type) { |
63 | # use '||' instead of 'or' to preserve $type in the error message |
64 | $type = $type_map{$type} |
65 | || confess qq["$type" doesn't look like a valid type (one of ${\join ', ', sort keys %type_map})]; |
66 | } |
67 | $type->{name} ||= 'optional'; |
68 | $type->{name} =~ /^(?:optional|required|prohibited)\z/ |
69 | or confess qq["$type->{name}" doesn't look like a valid name attribute (one of optional, required, prohibited)]; |
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70 | |
71 | $type->{shift} and _assert_valid_identifier $type->{shift}, 1; |
72 | $type->{attrs} and _assert_valid_attributes $type->{attrs}; |
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73 | |
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74 | $spec{$name} = $type; |
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75 | } |
76 | |
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77 | for my $kw (keys %spec) { |
78 | my $type = $spec{$kw}; |
79 | |
80 | $^H{HINTK_SHIFT_ . $kw} = $type->{shift} || ''; |
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81 | $^H{HINTK_ATTRS_ . $kw} = $type->{attrs} || ''; |
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82 | $^H{HINTK_NAME_ . $kw} = |
83 | $type->{name} eq 'prohibited' ? FLAG_NAME_PROHIBITED : |
84 | $type->{name} eq 'required' ? FLAG_NAME_REQUIRED : |
85 | FLAG_NAME_OPTIONAL |
86 | ; |
87 | $^H{+HINTK_KEYWORDS} .= "$kw "; |
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88 | } |
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89 | } |
90 | |
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91 | sub unimport { |
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92 | my $class = shift; |
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93 | |
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94 | if (!@_) { |
95 | delete $^H{+HINTK_KEYWORDS}; |
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96 | return; |
97 | } |
98 | |
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99 | for my $kw (@_) { |
100 | $^H{+HINTK_KEYWORDS} =~ s/(?<![^ ])\Q$kw\E //g; |
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101 | } |
102 | } |
103 | |
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104 | |
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105 | 'ok' |
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106 | |
107 | __END__ |
108 | |
109 | =head1 NAME |
110 | |
111 | Function::Parameters - subroutine definitions with parameter lists |
112 | |
113 | =head1 SYNOPSIS |
114 | |
115 | use Function::Parameters; |
116 | |
117 | fun foo($bar, $baz) { |
118 | return $bar + $baz; |
119 | } |
120 | |
121 | fun mymap($fun, @args) :(&@) { |
122 | my @res; |
123 | for (@args) { |
124 | push @res, $fun->($_); |
125 | } |
126 | @res |
127 | } |
128 | |
129 | print "$_\n" for mymap { $_ * 2 } 1 .. 4; |
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130 | |
131 | method set_name($name) { |
132 | $self->{name} = $name; |
133 | } |
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134 | |
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135 | =cut |
136 | |
137 | =pod |
138 | |
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139 | use Function::Parameters { |
140 | proc => 'function', |
141 | meth => 'method', |
142 | }; |
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143 | |
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144 | my $f = proc ($x) { $x * 2 }; |
145 | meth get_age() { |
146 | return $self->{age}; |
147 | } |
148 | |
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149 | =head1 DESCRIPTION |
150 | |
151 | This module lets you use parameter lists in your subroutines. Thanks to |
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152 | L<PL_keyword_plugin|perlapi/PL_keyword_plugin> it works without source filters. |
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153 | |
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154 | WARNING: This is my first attempt at writing L<XS code|perlxs> and I have |
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155 | almost no experience with perl's internals. So while this module might |
156 | appear to work, it could also conceivably make your programs segfault. |
157 | Consider this module alpha quality. |
158 | |
159 | =head2 Basic stuff |
160 | |
161 | To use this new functionality, you have to use C<fun> instead of C<sub> - |
162 | C<sub> continues to work as before. The syntax is almost the same as for |
163 | C<sub>, but after the subroutine name (or directly after C<fun> if you're |
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164 | writing an anonymous sub) you can write a parameter list in parentheses. This |
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165 | list consists of comma-separated variables. |
166 | |
167 | The effect of C<fun foo($bar, $baz) {> is as if you'd written |
168 | C<sub foo { my ($bar, $baz) = @_; >, i.e. the parameter list is simply |
169 | copied into C<my> and initialized from L<@_|perlvar/"@_">. |
170 | |
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171 | In addition you can use C<method>, which understands the same syntax as C<fun> |
172 | but automatically creates a C<$self> variable for you. So by writing |
173 | C<method foo($bar, $baz) {> you get the same effect as |
174 | C<sub foo { my $self = shift; my ($bar, $baz) = @_; >. |
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175 | |
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176 | =head2 Customizing the generated keywords |
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177 | |
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178 | You can customize the names of the keywords injected into your scope. To do |
179 | that you pass a hash reference in the import list: |
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180 | |
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181 | use Function::Parameters { proc => 'function', meth => 'method' }; # -or- |
182 | use Function::Parameters { proc => 'function' }; # -or- |
183 | use Function::Parameters { meth => 'method' }; |
184 | |
185 | The first line creates two keywords, C<proc> and C<meth> (for defining |
186 | functions and methods, respectively). The last two lines only create one |
187 | keyword. Generally the hash keys can be any identifiers you want while the |
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188 | values have to be either C<function>, C<method>, or a hash reference (see |
189 | below). The difference between C<function> and C<method> is that C<method>s |
190 | automatically L<shift|perlfunc/shift> their first argument into C<$self>. |
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191 | |
192 | The following shortcuts are available: |
193 | |
194 | use Function::Parameters; |
195 | # is equivalent to # |
196 | use Function::Parameters { fun => 'function', method => 'method' }; |
197 | |
198 | =cut |
199 | |
200 | =pod |
201 | |
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202 | The following shortcuts are deprecated and may be removed from a future version |
203 | of the module: |
204 | |
205 | # DEPRECATED |
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206 | use Function::Parameters 'foo'; |
207 | # is equivalent to # |
208 | use Function::Parameters { 'foo' => 'function' }; |
209 | |
210 | =cut |
211 | |
212 | =pod |
213 | |
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214 | # DEPRECATED |
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215 | use Function::Parameters 'foo', 'bar'; |
216 | # is equivalent to # |
217 | use Function::Parameters { 'foo' => 'function', 'bar' => 'method' }; |
218 | |
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219 | That is, if you want to pass arguments to L<Function::Parameters>, use a |
220 | hashref, not a list of strings. |
221 | |
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222 | You can customize things even more by passing a hashref instead of C<function> |
223 | or C<method>. This hash can have the following keys: |
224 | |
225 | =over |
226 | |
227 | =item C<name> |
228 | |
229 | Valid values: C<optional> (default), C<required> (all uses of this keyword must |
230 | specify a function name), and C<prohibited> (all uses of this keyword must not |
231 | specify a function name). This means a C<< name => 'prohibited' >> keyword can |
232 | only be used for defining anonymous functions. |
233 | |
234 | =item C<shift> |
235 | |
236 | Valid values: strings that look like a scalar variable. Any function created by |
237 | this keyword will automatically L<shift|perlfunc/shift> its first argument into |
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238 | a local variable whose name is specified here. |
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239 | |
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240 | =item C<attrs> |
241 | |
242 | Valid values: strings that are valid source code for attributes. Any value |
243 | specified here will be inserted as a subroutine attribute in the generated |
244 | code. Thus: |
245 | |
246 | use Function::Parameters { sub_l => { attrs => ':lvalue' } }; |
247 | sub_l foo() { |
248 | ... |
249 | } |
250 | |
251 | turns into |
252 | |
253 | sub foo :lvalue { |
254 | ... |
255 | } |
256 | |
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257 | =back |
258 | |
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259 | Plain C<'function'> is equivalent to C<< { name => 'optional' } >>, and plain |
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260 | C<'method'> is equivalent to |
261 | C<< { name => 'optional', shift => '$self', attrs => ':method' } >>. |
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262 | |
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263 | =head2 Syntax and generated code |
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264 | |
265 | Normally, Perl subroutines are not in scope in their own body, meaning the |
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266 | parser doesn't know the name C<foo> or its prototype while processing the body |
267 | of C<sub foo ($) { foo $bar[1], $bar[0]; }>, parsing it as |
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268 | C<$bar-E<gt>foo([1], $bar[0])>. Yes. You can add parens to change the |
269 | interpretation of this code, but C<foo($bar[1], $bar[0])> will only trigger |
270 | a I<foo() called too early to check prototype> warning. This module attempts |
271 | to fix all of this by adding a subroutine declaration before the definition, |
272 | so the parser knows the name (and possibly prototype) while it processes the |
273 | body. Thus C<fun foo($x) :($) { $x }> really turns into |
274 | C<sub foo ($); sub foo ($) { my ($x) = @_; $x }>. |
275 | |
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276 | If you need L<subroutine attributes|perlsub/"Subroutine Attributes">, you can |
277 | put them after the parameter list with their usual syntax. |
278 | |
279 | Syntactically, these new parameter lists live in the spot normally occupied |
280 | by L<prototypes|perlsub/"Prototypes">. However, you can include a prototype by |
281 | specifying it as the first attribute (this is syntactically unambiguous |
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282 | because normal attributes have to start with a letter while a prototype starts |
283 | with C<(>). |
284 | |
285 | As an example, the following declaration uses every feature available |
286 | (subroutine name, parameter list, prototype, attributes, and implicit |
287 | C<$self>): |
288 | |
289 | method foo($x, $y, @z) :($;$@) :lvalue :Banana(2 + 2) { |
290 | ... |
291 | } |
292 | |
293 | And here's what it turns into: |
294 | |
295 | sub foo ($;$@); sub foo ($;$@) :lvalue :Banana(2 + 2) { my $self = shift; my ($x, $y, @z) = @_; |
296 | ... |
297 | } |
298 | |
299 | Another example: |
300 | |
301 | my $coderef = fun ($p, $q) :(;$$) |
302 | :lvalue |
303 | :Gazebo((>:O)) { |
304 | ... |
305 | }; |
306 | |
307 | And the generated code: |
308 | |
309 | my $coderef = sub (;$$) :lvalue :Gazebo((>:O)) { my ($p, $q) = @_; |
310 | ... |
311 | }; |
312 | |
313 | =head2 Wrapping Function::Parameters |
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314 | |
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315 | If you want to wrap L<Function::Parameters>, you just have to call its |
316 | C<import> method. It always applies to the file that is currently being parsed |
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317 | and its effects are lexical (i.e. it works like L<warnings> or L<strict>): |
318 | |
319 | package Some::Wrapper; |
320 | use Function::Parameters (); |
321 | sub import { |
322 | Function::Parameters->import; |
323 | # or Function::Parameters->import(@other_import_args); |
324 | } |
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325 | |
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326 | =head1 AUTHOR |
327 | |
328 | Lukas Mai, C<< <l.mai at web.de> >> |
329 | |
330 | =head1 COPYRIGHT & LICENSE |
331 | |
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332 | Copyright 2010, 2011, 2012 Lukas Mai. |
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333 | |
334 | This program is free software; you can redistribute it and/or modify it |
335 | under the terms of either: the GNU General Public License as published |
336 | by the Free Software Foundation; or the Artistic License. |
337 | |
338 | See http://dev.perl.org/licenses/ for more information. |
339 | |
340 | =cut |