Commit | Line | Data |
7a63380c |
1 | package Function::Parameters; |
2 | |
7dd35535 |
3 | use v5.14.0; |
4 | |
7a63380c |
5 | use strict; |
6 | use warnings; |
7 | |
63915d26 |
8 | use Carp qw(confess); |
9 | |
db81d362 |
10 | use XSLoader; |
11 | BEGIN { |
8904fbfb |
12 | our $VERSION = '0.10_03'; |
db81d362 |
13 | XSLoader::load; |
7a63380c |
14 | } |
15 | |
2d5cf47a |
16 | sub _assert_valid_identifier { |
17 | my ($name, $with_dollar) = @_; |
18 | my $bonus = $with_dollar ? '\$' : ''; |
19 | $name =~ /^${bonus}[^\W\d]\w*\z/ |
20 | or confess qq{"$name" doesn't look like a valid identifier}; |
21 | } |
22 | |
b72eb6ee |
23 | sub _assert_valid_attributes { |
24 | my ($attrs) = @_; |
25 | $attrs =~ /^\s*:\s*[^\W\d]\w*\s*(?:(?:\s|:\s*)[^\W\d]\w*\s*)*(?:\(|\z)/ |
26 | or confess qq{"$attrs" doesn't look like valid attributes}; |
27 | } |
28 | |
125c067e |
29 | my @bare_arms = qw(function method); |
2d5cf47a |
30 | my %type_map = ( |
63915d26 |
31 | function => { |
32 | name => 'optional', |
33 | default_arguments => 1, |
34 | check_argument_count => 0, |
e158cf8f |
35 | named_parameters => 1, |
63915d26 |
36 | }, |
7947f7ce |
37 | method => { |
38 | name => 'optional', |
63915d26 |
39 | default_arguments => 1, |
40 | check_argument_count => 0, |
e158cf8f |
41 | named_parameters => 1, |
7947f7ce |
42 | attrs => ':method', |
63915d26 |
43 | shift => '$self', |
d8e5d540 |
44 | invocant => 1, |
7947f7ce |
45 | }, |
a23979e1 |
46 | classmethod => { |
47 | name => 'optional', |
63915d26 |
48 | default_arguments => 1, |
49 | check_argument_count => 0, |
e158cf8f |
50 | named_parameters => 1, |
698e861c |
51 | attributes => ':method', |
63915d26 |
52 | shift => '$class', |
d8e5d540 |
53 | invocant => 1, |
a23979e1 |
54 | }, |
2d5cf47a |
55 | ); |
7817d698 |
56 | for my $k (keys %type_map) { |
57 | $type_map{$k . '_strict'} = { |
58 | %{$type_map{$k}}, |
59 | check_argument_count => 1, |
60 | }; |
61 | } |
c9a39f6b |
62 | |
db81d362 |
63 | sub import { |
64 | my $class = shift; |
7a63380c |
65 | |
fcaf7811 |
66 | if (!@_) { |
67 | @_ = { |
68 | fun => 'function', |
69 | method => 'method', |
70 | }; |
71 | } |
72 | if (@_ == 1 && $_[0] eq ':strict') { |
73 | @_ = { |
74 | fun => 'function_strict', |
75 | method => 'method_strict', |
76 | }; |
77 | } |
125c067e |
78 | if (@_ == 1 && ref($_[0]) eq 'HASH') { |
fcaf7811 |
79 | @_ = map [$_, $_[0]{$_}], keys %{$_[0]}; |
125c067e |
80 | } |
7a63380c |
81 | |
125c067e |
82 | my %spec; |
83 | |
84 | my $bare = 0; |
85 | for my $proto (@_) { |
86 | my $item = ref $proto |
87 | ? $proto |
88 | : [$proto, $bare_arms[$bare++] || confess(qq{Don't know what to do with "$proto"})] |
89 | ; |
ae6e00b5 |
90 | my ($name, $proto_type) = @$item; |
2d5cf47a |
91 | _assert_valid_identifier $name; |
92 | |
ae6e00b5 |
93 | unless (ref $proto_type) { |
94 | # use '||' instead of 'or' to preserve $proto_type in the error message |
95 | $proto_type = $type_map{$proto_type} |
96 | || confess qq["$proto_type" doesn't look like a valid type (one of ${\join ', ', sort keys %type_map})]; |
2d5cf47a |
97 | } |
b72eb6ee |
98 | |
ae6e00b5 |
99 | my %type = %$proto_type; |
100 | my %clean; |
10acc8b1 |
101 | |
ae6e00b5 |
102 | $clean{name} = delete $type{name} || 'optional'; |
103 | $clean{name} =~ /^(?:optional|required|prohibited)\z/ |
104 | or confess qq["$clean{name}" doesn't look like a valid name attribute (one of optional, required, prohibited)]; |
10acc8b1 |
105 | |
ae6e00b5 |
106 | $clean{shift} = delete $type{shift} || ''; |
10acc8b1 |
107 | _assert_valid_identifier $clean{shift}, 1 if $clean{shift}; |
108 | |
698e861c |
109 | $clean{attrs} = join ' ', map delete $type{$_} || (), qw(attributes attrs); |
10acc8b1 |
110 | _assert_valid_attributes $clean{attrs} if $clean{attrs}; |
125c067e |
111 | |
59f51b8b |
112 | $clean{default_arguments} = |
113 | exists $type{default_arguments} |
114 | ? !!delete $type{default_arguments} |
115 | : 1 |
116 | ; |
63915d26 |
117 | $clean{check_argument_count} = !!delete $type{check_argument_count}; |
d8e5d540 |
118 | $clean{invocant} = !!delete $type{invocant}; |
e158cf8f |
119 | $clean{named_parameters} = !!delete $type{named_parameters}; |
63915d26 |
120 | |
ae6e00b5 |
121 | %type and confess "Invalid keyword property: @{[keys %type]}"; |
122 | |
123 | $spec{$name} = \%clean; |
125c067e |
124 | } |
125 | |
db81d362 |
126 | for my $kw (keys %spec) { |
127 | my $type = $spec{$kw}; |
128 | |
63915d26 |
129 | my $flags = |
130 | $type->{name} eq 'prohibited' ? FLAG_ANON_OK : |
131 | $type->{name} eq 'required' ? FLAG_NAME_OK : |
132 | FLAG_ANON_OK | FLAG_NAME_OK |
133 | ; |
134 | $flags |= FLAG_DEFAULT_ARGS if $type->{default_arguments}; |
135 | $flags |= FLAG_CHECK_NARGS if $type->{check_argument_count}; |
d8e5d540 |
136 | $flags |= FLAG_INVOCANT if $type->{invocant}; |
e158cf8f |
137 | $flags |= FLAG_NAMED_PARAMS if $type->{named_parameters}; |
63915d26 |
138 | $^H{HINTK_FLAGS_ . $kw} = $flags; |
ae6e00b5 |
139 | $^H{HINTK_SHIFT_ . $kw} = $type->{shift}; |
10acc8b1 |
140 | $^H{HINTK_ATTRS_ . $kw} = $type->{attrs}; |
db81d362 |
141 | $^H{+HINTK_KEYWORDS} .= "$kw "; |
125c067e |
142 | } |
eeb7df5f |
143 | } |
144 | |
db81d362 |
145 | sub unimport { |
eeb7df5f |
146 | my $class = shift; |
125c067e |
147 | |
db81d362 |
148 | if (!@_) { |
149 | delete $^H{+HINTK_KEYWORDS}; |
125c067e |
150 | return; |
151 | } |
152 | |
db81d362 |
153 | for my $kw (@_) { |
154 | $^H{+HINTK_KEYWORDS} =~ s/(?<![^ ])\Q$kw\E //g; |
125c067e |
155 | } |
156 | } |
157 | |
db81d362 |
158 | |
125c067e |
159 | 'ok' |
7a63380c |
160 | |
161 | __END__ |
162 | |
f2541b7d |
163 | =encoding UTF-8 |
164 | |
7a63380c |
165 | =head1 NAME |
166 | |
167 | Function::Parameters - subroutine definitions with parameter lists |
168 | |
169 | =head1 SYNOPSIS |
170 | |
81203272 |
171 | use Function::Parameters qw(:strict); |
7a63380c |
172 | |
698e861c |
173 | # simple function |
7a63380c |
174 | fun foo($bar, $baz) { |
175 | return $bar + $baz; |
176 | } |
177 | |
698e861c |
178 | # function with prototype |
d71d548b |
179 | fun mymap($fun, @args) |
180 | :(&@) |
181 | { |
7a63380c |
182 | my @res; |
183 | for (@args) { |
184 | push @res, $fun->($_); |
185 | } |
186 | @res |
187 | } |
188 | |
189 | print "$_\n" for mymap { $_ * 2 } 1 .. 4; |
125c067e |
190 | |
698e861c |
191 | # method with implicit $self |
125c067e |
192 | method set_name($name) { |
193 | $self->{name} = $name; |
194 | } |
d8e5d540 |
195 | |
196 | # method with explicit invocant |
197 | method new($class: %init) { |
198 | return bless { %init }, $class; |
199 | } |
200 | |
81203272 |
201 | # function with optional parameters |
698e861c |
202 | fun search($haystack, $needle = qr/^(?!)/, $offset = 0) { |
203 | ... |
204 | } |
d8e5d540 |
205 | |
81203272 |
206 | # method with named parameters |
207 | method resize(:$width, :$height) { |
208 | $self->{width} = $width; |
209 | $self->{height} = $height; |
698e861c |
210 | } |
8dbfd12d |
211 | |
81203272 |
212 | $obj->resize(height => 4, width => 5); |
8dbfd12d |
213 | |
81203272 |
214 | # function with named optional parameters |
215 | fun search($haystack, :$needle = qr/^(?!)/, :$offset = 0) { |
216 | ... |
217 | } |
8dbfd12d |
218 | |
81203272 |
219 | my $results = search $text, offset => 200; |
8dbfd12d |
220 | |
81203272 |
221 | =head1 DESCRIPTION |
8dbfd12d |
222 | |
81203272 |
223 | This module extends Perl with keywords that let you define functions with |
224 | parameter lists. It uses Perl's L<keyword plugin|perlapi/PL_keyword_plugin> |
225 | API, so it works reliably and doesn't require a source filter. |
226 | |
227 | =head2 Basics |
228 | |
229 | The anatomy of a function (as recognized by this module): |
230 | |
231 | =over |
8dbfd12d |
232 | |
81203272 |
233 | =item 1. |
234 | |
235 | The keyword introducing the function. |
236 | |
237 | =item 2. |
238 | |
239 | The function name (optional). |
240 | |
241 | =item 3. |
242 | |
243 | The parameter list (optional). |
244 | |
245 | =item 4. |
246 | |
247 | The prototype (optional). |
248 | |
249 | =item 5. |
250 | |
251 | The attribute list (optional). |
252 | |
253 | =item 6. |
254 | |
255 | The function body. |
256 | |
257 | =back |
258 | |
259 | Example: |
260 | |
261 | # (1) (2) (3) (4) (5) (6) |
262 | fun foo ($x, $y) :($$) :lvalue { ... } |
c9a39f6b |
263 | |
81203272 |
264 | # (1) (6) |
265 | my $f = fun { ... }; |
125c067e |
266 | |
81203272 |
267 | In the following section I'm going to describe all parts in order from simplest to most complex. |
7a63380c |
268 | |
81203272 |
269 | =head3 Body |
7a63380c |
270 | |
81203272 |
271 | This is just a normal block of statements, as with L<C<sub>|perlsub>. No surprises here. |
7a63380c |
272 | |
81203272 |
273 | =head3 Name |
7a63380c |
274 | |
81203272 |
275 | If present, it specifies the name of the function being defined. As with |
276 | L<C<sub>|perlsub>, if a name is present, the whole declaration is syntactically |
277 | a statement and its effects are performed at compile time (i.e. at runtime you |
278 | can call functions whose definitions only occur later in the file). If no name |
279 | is present, the declaration is an expression that evaluates to a reference to |
280 | the function in question. No surprises here either. |
7a63380c |
281 | |
81203272 |
282 | =head3 Attributes |
7a63380c |
283 | |
81203272 |
284 | Attributes are relatively unusual in Perl code, but if you want them, they work |
285 | exactly the same as with L<C<sub>|perlsub/Subroutine-Attributes>. |
c9a39f6b |
286 | |
81203272 |
287 | =head3 Prototype |
698e861c |
288 | |
81203272 |
289 | As with L<C<sub>|perlsub/Prototypes>, a prototype, if present, contains hints as to how |
290 | the compiler should parse calls to this function. This means prototypes have no |
291 | effect if the function call is compiled before the function declaration has |
292 | been seen by the compiler or if the function to call is only determined at |
293 | runtime (e.g. because it's called as a method or through a reference). |
698e861c |
294 | |
81203272 |
295 | With L<C<sub>|perlsub>, a prototype comes directly after the function name (if |
296 | any). C<Function::Parameters> reserves this spot for the |
297 | L<parameter list|/"Parameter list">. To specify a prototype, put it as the |
298 | first attribute (e.g. C<fun foo :(&$$)>). This is syntactically unambiguous |
299 | because normal L<attributes|/Attributes> need a name after the colon. |
7a63380c |
300 | |
81203272 |
301 | =head3 Parameter list |
125c067e |
302 | |
81203272 |
303 | The parameter list is a list of variables enclosed in parentheses, except it's |
304 | actually a bit more complicated than that. A parameter list can include the |
305 | following 6 parts, all of which are optional: |
125c067e |
306 | |
81203272 |
307 | =over |
125c067e |
308 | |
81203272 |
309 | =item 1. Invocant |
125c067e |
310 | |
81203272 |
311 | This is a scalar variable followed by a colon (C<:>) and no comma. If an |
312 | invocant is present in the parameter list, the first element of |
313 | L<C<@_>|perlvar/@ARG> is automatically L<C<shift>ed|perlfunc/shift> off and |
314 | placed in this variable. This is intended for methods: |
125c067e |
315 | |
81203272 |
316 | method new($class: %init) { |
317 | return bless { %init }, $class; |
318 | } |
319 | |
320 | method throw($self:) { |
321 | die $self; |
322 | } |
125c067e |
323 | |
81203272 |
324 | =item 2. Required positional parameters |
fcaf7811 |
325 | |
81203272 |
326 | The most common kind of parameter. This is simply a comma-separated list of |
327 | scalars, which are filled from left to right with the arguments that the caller |
328 | passed in: |
fcaf7811 |
329 | |
81203272 |
330 | fun add($x, $y) { |
331 | return $x + $y; |
332 | } |
333 | |
334 | say add(2, 3); # "5" |
335 | |
336 | =item 3. Optional positional parameters |
337 | |
338 | Parameters can be marked as optional by putting an equals sign (C<=>) and an |
339 | expression (the "default argument") after them. If no corresponding argument is |
340 | passed in by the caller, the default argument will be used to initialize the |
341 | parameter: |
342 | |
343 | fun scale($base, $factor = 2) { |
344 | return $base * $factor; |
345 | } |
346 | |
347 | say scale(3, 5); # "15" |
348 | say scale(3); # "6" |
349 | |
350 | The default argument is I<not> cached. Every time a function is called with |
351 | some optional arguments missing, the corresponding default arguments are |
352 | evaluated from left to right. This makes no difference for a value like C<2> |
353 | but it is important for expressions with side effects, such as reference |
354 | constructors (C<[]>, C<{}>) or function calls. |
355 | |
356 | Default arguments see not only the surrounding lexical scope of their function |
357 | but also any preceding parameters. This allows the creation of dynamic defaults |
358 | based on previous arguments: |
359 | |
360 | method set_name($self: $nick = $self->default_nick, $real_name = $nick) { |
361 | $self->{nick} = $nick; |
362 | $self->{real_name} = $real_name; |
363 | } |
364 | |
365 | $obj->set_name("simplicio"); # same as: $obj->set_name("simplicio", "simplicio"); |
63a24d7c |
366 | |
81203272 |
367 | Because default arguments are actually evaluated as part of the function body, |
368 | you can also do silly things like this: |
369 | |
370 | fun foo($n = return "nope") { |
371 | "you gave me $n" |
372 | } |
373 | |
374 | say foo(2 + 2); # "you gave me 4" |
375 | say foo(); # "nope" |
376 | |
377 | =item 4. Required named parameters |
378 | |
379 | By putting a colon (C<:>) in front of a parameter you can make it named |
380 | instead of positional: |
381 | |
382 | fun rectangle(:$width, :$height) { |
383 | ... |
384 | } |
385 | |
386 | rectangle(width => 2, height => 5); |
387 | rectangle(height => 5, width => 2); # same thing! |
388 | |
389 | That is, the caller must specify a key name in addition to the value, but in |
390 | exchange the order of the arguments doesn't matter anymore. As with hash |
391 | initialization, you can specify the same key multiple times and the last |
392 | occurrence wins: |
393 | |
394 | rectangle(height => 1, width => 2, height => 2, height => 5; |
395 | # same as: rectangle(width => 2, height => 5); |
396 | |
397 | You can combine positional and named parameters as long as the positional |
398 | parameters come first: |
399 | |
400 | fun named_rectangle($name, :$width, :$height) { |
401 | ... |
402 | } |
403 | |
404 | named_rectangle("Avocado", width => 0.5, height => 1.2); |
405 | |
406 | =item 5. Optional named parameters |
407 | |
408 | As with positional parameters, you can make named parameters optional by |
409 | specifying a default argument after an equals sign (C<=>): |
410 | |
411 | fun rectangle(:$width, :$height, :$color = "chartreuse") { |
412 | ... |
413 | } |
414 | |
415 | rectangle(height => 10, width => 5); |
416 | # same as: rectangle(height => 10, width => 5, color => "chartreuse"); |
125c067e |
417 | |
418 | =cut |
419 | |
420 | =pod |
81203272 |
421 | |
422 | fun get($url, :$cookie_jar = HTTP::Cookies->new(), :$referrer = $url) { |
423 | ... |
424 | } |
125c067e |
425 | |
81203272 |
426 | my $data = get "http://www.example.com/", referrer => undef; # overrides $referrer = $url |
125c067e |
427 | |
81203272 |
428 | The above example shows that passing any value (even C<undef>) will override |
429 | the default argument. |
63a24d7c |
430 | |
81203272 |
431 | =item 6. Slurpy parameter |
ce052c57 |
432 | |
81203272 |
433 | Finally you can put an array or hash in the parameter list, which will gobble |
434 | up the remaining arguments (if any): |
ce052c57 |
435 | |
81203272 |
436 | fun foo($x, $y, @rest) { ... } |
437 | |
438 | foo "a", "b"; # $x = "a", $y = "b", @rest = () |
439 | foo "a", "b", "c"; # $x = "a", $y = "b", @rest = ("c") |
440 | foo "a", "b", "c", "d"; # $x = "a", $y = "b", @rest = ("c", "d") |
ce052c57 |
441 | |
81203272 |
442 | If you combine this with named parameters, the slurpy parameter will end up |
443 | containing all unrecognized keys: |
ce052c57 |
444 | |
81203272 |
445 | fun bar(:$size, @whatev) { ... } |
446 | |
447 | bar weight => 20, size => 2, location => [0, -3]; |
448 | # $size = 2, @whatev = ('weight', 20, 'location', [0, -3]) |
ce052c57 |
449 | |
81203272 |
450 | =back |
ce052c57 |
451 | |
81203272 |
452 | Apart from the L<C<shift>|perlfunc/shift> performed by the L<invocant|/"1. |
453 | Invocant">, all of the above leave L<C<@_>|perlvar/@ARG> unchanged; and if you |
454 | don't specify a parameter list at all, L<C<@_>|perlvar/@ARG> is all you get. |
d8e5d540 |
455 | |
81203272 |
456 | =head3 Keyword |
d8e5d540 |
457 | |
81203272 |
458 | The keywords provided by C<Function::Parameters> are customizable. Since |
459 | C<Function::Parameters> is actually a L<pragma|perlpragma>, the provided |
460 | keywords have lexical scope. The following import variants can be used: |
d8e5d540 |
461 | |
81203272 |
462 | =over |
273c6544 |
463 | |
81203272 |
464 | =item C<use Function::Parameters ':strict'> |
273c6544 |
465 | |
81203272 |
466 | Provides the keywords C<fun> and C<method> (described below) and enables |
467 | argument checks so that calling a function and omitting a required argument (or |
468 | passing too many arguments) will throw an error. |
273c6544 |
469 | |
81203272 |
470 | =item C<use Function::Parameters> |
273c6544 |
471 | |
81203272 |
472 | Provides the keywords C<fun> and C<method> (described below) and enables |
473 | "lax" mode: Omitting a required argument sets it to C<undef> while excess |
474 | arguments are silently ignored. |
273c6544 |
475 | |
81203272 |
476 | =item C<< use Function::Parameters { KEYWORD1 => TYPE1, KEYWORD2 => TYPE2, ... } >> |
698e861c |
477 | |
81203272 |
478 | Provides completely custom keywords as described by their types. A "type" is |
479 | either a string (one of the predefined types C<function>, C<method>, |
480 | C<classmethod>, C<function_strict>, C<method_strict>, C<classmethod_strict>) or |
481 | a reference to a hash with the following keys: |
698e861c |
482 | |
81203272 |
483 | =over |
698e861c |
484 | |
81203272 |
485 | =item C<name> |
698e861c |
486 | |
81203272 |
487 | Valid values: C<optional> (default), C<required> (all functions defined with |
488 | this keyword must have a name), and C<prohibited> (functions defined with this |
489 | keyword must be anonymous). |
698e861c |
490 | |
81203272 |
491 | =item C<shift> |
698e861c |
492 | |
81203272 |
493 | Valid values: strings that look like scalar variables. This lets you specify a |
494 | default L<invocant|/"1. Invocant">, i.e. a function defined with this keyword |
495 | that doesn't have an explicit invocant in its parameter list will automatically |
496 | L<C<shift>|perlfunc/shift> its first argument into the variable specified here. |
698e861c |
497 | |
81203272 |
498 | =item C<invocant> |
698e861c |
499 | |
81203272 |
500 | Valid values: booleans. If you set this to a true value, the keyword will |
501 | accept L<invocants|/"1. Invocant"> in parameter lists; otherwise specifying |
502 | an invocant in a function defined with this keyword is a syntax error. |
698e861c |
503 | |
81203272 |
504 | =item C<attributes> |
698e861c |
505 | |
81203272 |
506 | Valid values: strings containing (source code for) attributes. This causes any |
507 | function defined with this keyword to have the specified |
508 | L<attributes|attributes> (in addition to any attributes specified in the |
509 | function definition itself). |
698e861c |
510 | |
81203272 |
511 | =item C<default_arguments> |
698e861c |
512 | |
81203272 |
513 | Valid values: booleans. This property is on by default; use |
514 | C<< default_arguments => 0 >> to turn it off. This controls whether optional |
515 | parameters are allowed. If it is turned off, using C<=> in parameter lists is |
516 | a syntax error. |
698e861c |
517 | |
81203272 |
518 | =item C<check_argument_count> |
698e861c |
519 | |
81203272 |
520 | Valid values: booleans. If turned on, functions defined with this keyword will |
521 | automatically check that they have been passed all required arguments and no |
522 | excess arguments. If this check fails, an exception will by thrown via |
523 | L<C<Carp::croak>|Carp>. |
698e861c |
524 | |
ce052c57 |
525 | =back |
526 | |
81203272 |
527 | The predefined type C<function> is equivalent to: |
698e861c |
528 | |
529 | { |
530 | name => 'optional', |
81203272 |
531 | invocant => 0, |
698e861c |
532 | default_arguments => 1, |
533 | check_argument_count => 0, |
534 | } |
535 | |
81203272 |
536 | These are all default values, so C<function> is also equivalent to C<{}>. |
698e861c |
537 | |
81203272 |
538 | C<method> is equivalent to: |
698e861c |
539 | |
540 | { |
541 | name => 'optional', |
698e861c |
542 | shift => '$self', |
d8e5d540 |
543 | invocant => 1, |
81203272 |
544 | attributes => ':method', |
545 | default_arguments => 1, |
546 | check_argument_count => 0, |
698e861c |
547 | } |
548 | |
7817d698 |
549 | |
81203272 |
550 | C<classmethod> is equivalent to: |
698e861c |
551 | |
552 | { |
553 | name => 'optional', |
698e861c |
554 | shift => '$class', |
d8e5d540 |
555 | invocant => 1, |
81203272 |
556 | attributes => ':method', |
557 | default_arguments => 1, |
558 | check_argument_count => 0, |
698e861c |
559 | } |
ce052c57 |
560 | |
81203272 |
561 | C<function_strict>, C<method_strict>, and |
562 | C<classmethod_strict> are like C<function>, C<method>, and |
563 | C<classmethod>, respectively, but with C<< check_argument_count => 1 >>. |
63a24d7c |
564 | |
81203272 |
565 | =back |
63a24d7c |
566 | |
81203272 |
567 | Plain C<use Function::Parameters> is equivalent to |
568 | C<< use Function::Parameters { fun => 'function', method => 'method' } >>. |
63a24d7c |
569 | |
81203272 |
570 | C<use Function::Parameters qw(:strict)> is equivalent to |
571 | C<< use Function::Parameters { fun => 'function_strict', method => 'method_strict' } >>. |
63a24d7c |
572 | |
81203272 |
573 | =head2 Wrapping C<Function::Parameters> |
125c067e |
574 | |
81203272 |
575 | If you want to write a wrapper around C<Function::Parameters>, you only have to |
576 | call its C<import> method. Due to its L<pragma|perlpragma> nature it always |
577 | affects the file that is currently being compiled. |
63a24d7c |
578 | |
579 | package Some::Wrapper; |
580 | use Function::Parameters (); |
581 | sub import { |
582 | Function::Parameters->import; |
698e861c |
583 | # or Function::Parameters->import(@custom_import_args); |
63a24d7c |
584 | } |
eeb7df5f |
585 | |
81203272 |
586 | =head2 How it works |
587 | |
588 | The module is actually written in L<C|perlxs> and uses |
589 | L<C<PL_keyword_plugin>|perlapi/PL_keyword_plugin> to generate opcodes directly. |
590 | However, you can run L<C<perl -MO=Deparse ...>|B::Deparse> on your code to see |
591 | what happens under the hood. In the simplest case (no argument checks, possibly |
592 | an L<invocant|/"1. Invocant">, required positional/slurpy parameters only), the |
593 | generated code corresponds to: |
594 | |
595 | fun foo($x, $y, @z) { ... } |
596 | # ... turns into ... |
597 | sub foo { my ($x, $y, @z) = @_; sub foo; ... } |
598 | |
599 | method bar($x, $y, @z) { ... } |
600 | # ... turns into ... |
601 | sub bar :method { my $self = shift; my ($x, $y, @z) = @_; sub bar; ... } |
602 | |
7a63380c |
603 | =head1 AUTHOR |
604 | |
605 | Lukas Mai, C<< <l.mai at web.de> >> |
606 | |
607 | =head1 COPYRIGHT & LICENSE |
608 | |
db81d362 |
609 | Copyright 2010, 2011, 2012 Lukas Mai. |
7a63380c |
610 | |
611 | This program is free software; you can redistribute it and/or modify it |
612 | under the terms of either: the GNU General Public License as published |
613 | by the Free Software Foundation; or the Artistic License. |
614 | |
615 | See http://dev.perl.org/licenses/ for more information. |
616 | |
617 | =cut |