Commit | Line | Data |
7a63380c |
1 | package Function::Parameters; |
2 | |
7dd35535 |
3 | use v5.14.0; |
4 | |
7a63380c |
5 | use warnings; |
6 | |
63915d26 |
7 | use Carp qw(confess); |
8 | |
db81d362 |
9 | use XSLoader; |
10 | BEGIN { |
e1e43949 |
11 | our $VERSION = '1.00'; |
db81d362 |
12 | XSLoader::load; |
7a63380c |
13 | } |
14 | |
2d5cf47a |
15 | sub _assert_valid_identifier { |
16 | my ($name, $with_dollar) = @_; |
17 | my $bonus = $with_dollar ? '\$' : ''; |
18 | $name =~ /^${bonus}[^\W\d]\w*\z/ |
19 | or confess qq{"$name" doesn't look like a valid identifier}; |
20 | } |
21 | |
b72eb6ee |
22 | sub _assert_valid_attributes { |
23 | my ($attrs) = @_; |
24 | $attrs =~ /^\s*:\s*[^\W\d]\w*\s*(?:(?:\s|:\s*)[^\W\d]\w*\s*)*(?:\(|\z)/ |
25 | or confess qq{"$attrs" doesn't look like valid attributes}; |
26 | } |
27 | |
125c067e |
28 | my @bare_arms = qw(function method); |
2d5cf47a |
29 | my %type_map = ( |
63915d26 |
30 | function => { |
31 | name => 'optional', |
32 | default_arguments => 1, |
33 | check_argument_count => 0, |
e158cf8f |
34 | named_parameters => 1, |
63915d26 |
35 | }, |
7947f7ce |
36 | method => { |
37 | name => 'optional', |
63915d26 |
38 | default_arguments => 1, |
39 | check_argument_count => 0, |
e158cf8f |
40 | named_parameters => 1, |
7947f7ce |
41 | attrs => ':method', |
63915d26 |
42 | shift => '$self', |
d8e5d540 |
43 | invocant => 1, |
7947f7ce |
44 | }, |
a23979e1 |
45 | classmethod => { |
46 | name => 'optional', |
63915d26 |
47 | default_arguments => 1, |
48 | check_argument_count => 0, |
e158cf8f |
49 | named_parameters => 1, |
698e861c |
50 | attributes => ':method', |
63915d26 |
51 | shift => '$class', |
d8e5d540 |
52 | invocant => 1, |
a23979e1 |
53 | }, |
2d5cf47a |
54 | ); |
7817d698 |
55 | for my $k (keys %type_map) { |
56 | $type_map{$k . '_strict'} = { |
57 | %{$type_map{$k}}, |
58 | check_argument_count => 1, |
59 | }; |
60 | } |
c9a39f6b |
61 | |
db81d362 |
62 | sub import { |
63 | my $class = shift; |
7a63380c |
64 | |
fcaf7811 |
65 | if (!@_) { |
66 | @_ = { |
67 | fun => 'function', |
68 | method => 'method', |
69 | }; |
70 | } |
71 | if (@_ == 1 && $_[0] eq ':strict') { |
72 | @_ = { |
73 | fun => 'function_strict', |
74 | method => 'method_strict', |
75 | }; |
76 | } |
125c067e |
77 | if (@_ == 1 && ref($_[0]) eq 'HASH') { |
fcaf7811 |
78 | @_ = map [$_, $_[0]{$_}], keys %{$_[0]}; |
125c067e |
79 | } |
7a63380c |
80 | |
125c067e |
81 | my %spec; |
82 | |
83 | my $bare = 0; |
84 | for my $proto (@_) { |
85 | my $item = ref $proto |
86 | ? $proto |
87 | : [$proto, $bare_arms[$bare++] || confess(qq{Don't know what to do with "$proto"})] |
88 | ; |
ae6e00b5 |
89 | my ($name, $proto_type) = @$item; |
2d5cf47a |
90 | _assert_valid_identifier $name; |
91 | |
ae6e00b5 |
92 | unless (ref $proto_type) { |
93 | # use '||' instead of 'or' to preserve $proto_type in the error message |
94 | $proto_type = $type_map{$proto_type} |
95 | || confess qq["$proto_type" doesn't look like a valid type (one of ${\join ', ', sort keys %type_map})]; |
2d5cf47a |
96 | } |
b72eb6ee |
97 | |
ae6e00b5 |
98 | my %type = %$proto_type; |
99 | my %clean; |
10acc8b1 |
100 | |
ae6e00b5 |
101 | $clean{name} = delete $type{name} || 'optional'; |
102 | $clean{name} =~ /^(?:optional|required|prohibited)\z/ |
103 | or confess qq["$clean{name}" doesn't look like a valid name attribute (one of optional, required, prohibited)]; |
10acc8b1 |
104 | |
ae6e00b5 |
105 | $clean{shift} = delete $type{shift} || ''; |
10acc8b1 |
106 | _assert_valid_identifier $clean{shift}, 1 if $clean{shift}; |
107 | |
698e861c |
108 | $clean{attrs} = join ' ', map delete $type{$_} || (), qw(attributes attrs); |
10acc8b1 |
109 | _assert_valid_attributes $clean{attrs} if $clean{attrs}; |
125c067e |
110 | |
59f51b8b |
111 | $clean{default_arguments} = |
112 | exists $type{default_arguments} |
113 | ? !!delete $type{default_arguments} |
114 | : 1 |
115 | ; |
63915d26 |
116 | $clean{check_argument_count} = !!delete $type{check_argument_count}; |
d8e5d540 |
117 | $clean{invocant} = !!delete $type{invocant}; |
e158cf8f |
118 | $clean{named_parameters} = !!delete $type{named_parameters}; |
63915d26 |
119 | |
ae6e00b5 |
120 | %type and confess "Invalid keyword property: @{[keys %type]}"; |
121 | |
122 | $spec{$name} = \%clean; |
125c067e |
123 | } |
124 | |
db81d362 |
125 | for my $kw (keys %spec) { |
126 | my $type = $spec{$kw}; |
127 | |
63915d26 |
128 | my $flags = |
129 | $type->{name} eq 'prohibited' ? FLAG_ANON_OK : |
130 | $type->{name} eq 'required' ? FLAG_NAME_OK : |
131 | FLAG_ANON_OK | FLAG_NAME_OK |
132 | ; |
133 | $flags |= FLAG_DEFAULT_ARGS if $type->{default_arguments}; |
134 | $flags |= FLAG_CHECK_NARGS if $type->{check_argument_count}; |
d8e5d540 |
135 | $flags |= FLAG_INVOCANT if $type->{invocant}; |
e158cf8f |
136 | $flags |= FLAG_NAMED_PARAMS if $type->{named_parameters}; |
63915d26 |
137 | $^H{HINTK_FLAGS_ . $kw} = $flags; |
ae6e00b5 |
138 | $^H{HINTK_SHIFT_ . $kw} = $type->{shift}; |
10acc8b1 |
139 | $^H{HINTK_ATTRS_ . $kw} = $type->{attrs}; |
db81d362 |
140 | $^H{+HINTK_KEYWORDS} .= "$kw "; |
125c067e |
141 | } |
eeb7df5f |
142 | } |
143 | |
db81d362 |
144 | sub unimport { |
eeb7df5f |
145 | my $class = shift; |
125c067e |
146 | |
db81d362 |
147 | if (!@_) { |
148 | delete $^H{+HINTK_KEYWORDS}; |
125c067e |
149 | return; |
150 | } |
151 | |
db81d362 |
152 | for my $kw (@_) { |
153 | $^H{+HINTK_KEYWORDS} =~ s/(?<![^ ])\Q$kw\E //g; |
125c067e |
154 | } |
155 | } |
156 | |
db81d362 |
157 | |
125c067e |
158 | 'ok' |
7a63380c |
159 | |
160 | __END__ |
161 | |
f2541b7d |
162 | =encoding UTF-8 |
163 | |
7a63380c |
164 | =head1 NAME |
165 | |
166 | Function::Parameters - subroutine definitions with parameter lists |
167 | |
168 | =head1 SYNOPSIS |
169 | |
81203272 |
170 | use Function::Parameters qw(:strict); |
7a63380c |
171 | |
698e861c |
172 | # simple function |
7a63380c |
173 | fun foo($bar, $baz) { |
174 | return $bar + $baz; |
175 | } |
176 | |
698e861c |
177 | # function with prototype |
d71d548b |
178 | fun mymap($fun, @args) |
179 | :(&@) |
180 | { |
7a63380c |
181 | my @res; |
182 | for (@args) { |
183 | push @res, $fun->($_); |
184 | } |
185 | @res |
186 | } |
187 | |
188 | print "$_\n" for mymap { $_ * 2 } 1 .. 4; |
125c067e |
189 | |
698e861c |
190 | # method with implicit $self |
125c067e |
191 | method set_name($name) { |
192 | $self->{name} = $name; |
193 | } |
d8e5d540 |
194 | |
195 | # method with explicit invocant |
196 | method new($class: %init) { |
197 | return bless { %init }, $class; |
198 | } |
199 | |
81203272 |
200 | # function with optional parameters |
698e861c |
201 | fun search($haystack, $needle = qr/^(?!)/, $offset = 0) { |
202 | ... |
203 | } |
d8e5d540 |
204 | |
81203272 |
205 | # method with named parameters |
206 | method resize(:$width, :$height) { |
207 | $self->{width} = $width; |
208 | $self->{height} = $height; |
698e861c |
209 | } |
8dbfd12d |
210 | |
81203272 |
211 | $obj->resize(height => 4, width => 5); |
8dbfd12d |
212 | |
81203272 |
213 | # function with named optional parameters |
214 | fun search($haystack, :$needle = qr/^(?!)/, :$offset = 0) { |
215 | ... |
216 | } |
8dbfd12d |
217 | |
81203272 |
218 | my $results = search $text, offset => 200; |
8dbfd12d |
219 | |
81203272 |
220 | =head1 DESCRIPTION |
8dbfd12d |
221 | |
81203272 |
222 | This module extends Perl with keywords that let you define functions with |
223 | parameter lists. It uses Perl's L<keyword plugin|perlapi/PL_keyword_plugin> |
224 | API, so it works reliably and doesn't require a source filter. |
225 | |
226 | =head2 Basics |
227 | |
228 | The anatomy of a function (as recognized by this module): |
229 | |
230 | =over |
8dbfd12d |
231 | |
81203272 |
232 | =item 1. |
233 | |
234 | The keyword introducing the function. |
235 | |
236 | =item 2. |
237 | |
238 | The function name (optional). |
239 | |
240 | =item 3. |
241 | |
242 | The parameter list (optional). |
243 | |
244 | =item 4. |
245 | |
246 | The prototype (optional). |
247 | |
248 | =item 5. |
249 | |
250 | The attribute list (optional). |
251 | |
252 | =item 6. |
253 | |
254 | The function body. |
255 | |
256 | =back |
257 | |
258 | Example: |
259 | |
260 | # (1) (2) (3) (4) (5) (6) |
261 | fun foo ($x, $y) :($$) :lvalue { ... } |
c9a39f6b |
262 | |
81203272 |
263 | # (1) (6) |
264 | my $f = fun { ... }; |
125c067e |
265 | |
81203272 |
266 | In the following section I'm going to describe all parts in order from simplest to most complex. |
7a63380c |
267 | |
81203272 |
268 | =head3 Body |
7a63380c |
269 | |
81203272 |
270 | This is just a normal block of statements, as with L<C<sub>|perlsub>. No surprises here. |
7a63380c |
271 | |
81203272 |
272 | =head3 Name |
7a63380c |
273 | |
81203272 |
274 | If present, it specifies the name of the function being defined. As with |
275 | L<C<sub>|perlsub>, if a name is present, the whole declaration is syntactically |
276 | a statement and its effects are performed at compile time (i.e. at runtime you |
277 | can call functions whose definitions only occur later in the file). If no name |
278 | is present, the declaration is an expression that evaluates to a reference to |
279 | the function in question. No surprises here either. |
7a63380c |
280 | |
81203272 |
281 | =head3 Attributes |
7a63380c |
282 | |
81203272 |
283 | Attributes are relatively unusual in Perl code, but if you want them, they work |
284 | exactly the same as with L<C<sub>|perlsub/Subroutine-Attributes>. |
c9a39f6b |
285 | |
81203272 |
286 | =head3 Prototype |
698e861c |
287 | |
81203272 |
288 | As with L<C<sub>|perlsub/Prototypes>, a prototype, if present, contains hints as to how |
289 | the compiler should parse calls to this function. This means prototypes have no |
290 | effect if the function call is compiled before the function declaration has |
291 | been seen by the compiler or if the function to call is only determined at |
292 | runtime (e.g. because it's called as a method or through a reference). |
698e861c |
293 | |
81203272 |
294 | With L<C<sub>|perlsub>, a prototype comes directly after the function name (if |
295 | any). C<Function::Parameters> reserves this spot for the |
296 | L<parameter list|/"Parameter list">. To specify a prototype, put it as the |
297 | first attribute (e.g. C<fun foo :(&$$)>). This is syntactically unambiguous |
298 | because normal L<attributes|/Attributes> need a name after the colon. |
7a63380c |
299 | |
81203272 |
300 | =head3 Parameter list |
125c067e |
301 | |
81203272 |
302 | The parameter list is a list of variables enclosed in parentheses, except it's |
303 | actually a bit more complicated than that. A parameter list can include the |
304 | following 6 parts, all of which are optional: |
125c067e |
305 | |
81203272 |
306 | =over |
125c067e |
307 | |
81203272 |
308 | =item 1. Invocant |
125c067e |
309 | |
81203272 |
310 | This is a scalar variable followed by a colon (C<:>) and no comma. If an |
311 | invocant is present in the parameter list, the first element of |
312 | L<C<@_>|perlvar/@ARG> is automatically L<C<shift>ed|perlfunc/shift> off and |
313 | placed in this variable. This is intended for methods: |
125c067e |
314 | |
81203272 |
315 | method new($class: %init) { |
316 | return bless { %init }, $class; |
317 | } |
318 | |
319 | method throw($self:) { |
320 | die $self; |
321 | } |
125c067e |
322 | |
81203272 |
323 | =item 2. Required positional parameters |
fcaf7811 |
324 | |
81203272 |
325 | The most common kind of parameter. This is simply a comma-separated list of |
326 | scalars, which are filled from left to right with the arguments that the caller |
327 | passed in: |
fcaf7811 |
328 | |
81203272 |
329 | fun add($x, $y) { |
330 | return $x + $y; |
331 | } |
332 | |
333 | say add(2, 3); # "5" |
334 | |
335 | =item 3. Optional positional parameters |
336 | |
337 | Parameters can be marked as optional by putting an equals sign (C<=>) and an |
338 | expression (the "default argument") after them. If no corresponding argument is |
339 | passed in by the caller, the default argument will be used to initialize the |
340 | parameter: |
341 | |
342 | fun scale($base, $factor = 2) { |
343 | return $base * $factor; |
344 | } |
345 | |
346 | say scale(3, 5); # "15" |
347 | say scale(3); # "6" |
348 | |
349 | The default argument is I<not> cached. Every time a function is called with |
350 | some optional arguments missing, the corresponding default arguments are |
351 | evaluated from left to right. This makes no difference for a value like C<2> |
352 | but it is important for expressions with side effects, such as reference |
353 | constructors (C<[]>, C<{}>) or function calls. |
354 | |
355 | Default arguments see not only the surrounding lexical scope of their function |
356 | but also any preceding parameters. This allows the creation of dynamic defaults |
357 | based on previous arguments: |
358 | |
359 | method set_name($self: $nick = $self->default_nick, $real_name = $nick) { |
360 | $self->{nick} = $nick; |
361 | $self->{real_name} = $real_name; |
362 | } |
363 | |
364 | $obj->set_name("simplicio"); # same as: $obj->set_name("simplicio", "simplicio"); |
63a24d7c |
365 | |
81203272 |
366 | Because default arguments are actually evaluated as part of the function body, |
367 | you can also do silly things like this: |
368 | |
369 | fun foo($n = return "nope") { |
370 | "you gave me $n" |
371 | } |
372 | |
373 | say foo(2 + 2); # "you gave me 4" |
374 | say foo(); # "nope" |
375 | |
376 | =item 4. Required named parameters |
377 | |
378 | By putting a colon (C<:>) in front of a parameter you can make it named |
379 | instead of positional: |
380 | |
381 | fun rectangle(:$width, :$height) { |
382 | ... |
383 | } |
384 | |
385 | rectangle(width => 2, height => 5); |
386 | rectangle(height => 5, width => 2); # same thing! |
387 | |
388 | That is, the caller must specify a key name in addition to the value, but in |
389 | exchange the order of the arguments doesn't matter anymore. As with hash |
390 | initialization, you can specify the same key multiple times and the last |
391 | occurrence wins: |
392 | |
393 | rectangle(height => 1, width => 2, height => 2, height => 5; |
394 | # same as: rectangle(width => 2, height => 5); |
395 | |
396 | You can combine positional and named parameters as long as the positional |
397 | parameters come first: |
398 | |
399 | fun named_rectangle($name, :$width, :$height) { |
400 | ... |
401 | } |
402 | |
403 | named_rectangle("Avocado", width => 0.5, height => 1.2); |
404 | |
405 | =item 5. Optional named parameters |
406 | |
407 | As with positional parameters, you can make named parameters optional by |
408 | specifying a default argument after an equals sign (C<=>): |
409 | |
410 | fun rectangle(:$width, :$height, :$color = "chartreuse") { |
411 | ... |
412 | } |
413 | |
414 | rectangle(height => 10, width => 5); |
415 | # same as: rectangle(height => 10, width => 5, color => "chartreuse"); |
125c067e |
416 | |
417 | =cut |
418 | |
419 | =pod |
81203272 |
420 | |
421 | fun get($url, :$cookie_jar = HTTP::Cookies->new(), :$referrer = $url) { |
422 | ... |
423 | } |
125c067e |
424 | |
81203272 |
425 | my $data = get "http://www.example.com/", referrer => undef; # overrides $referrer = $url |
125c067e |
426 | |
81203272 |
427 | The above example shows that passing any value (even C<undef>) will override |
428 | the default argument. |
63a24d7c |
429 | |
81203272 |
430 | =item 6. Slurpy parameter |
ce052c57 |
431 | |
81203272 |
432 | Finally you can put an array or hash in the parameter list, which will gobble |
433 | up the remaining arguments (if any): |
ce052c57 |
434 | |
81203272 |
435 | fun foo($x, $y, @rest) { ... } |
436 | |
437 | foo "a", "b"; # $x = "a", $y = "b", @rest = () |
438 | foo "a", "b", "c"; # $x = "a", $y = "b", @rest = ("c") |
439 | foo "a", "b", "c", "d"; # $x = "a", $y = "b", @rest = ("c", "d") |
ce052c57 |
440 | |
81203272 |
441 | If you combine this with named parameters, the slurpy parameter will end up |
442 | containing all unrecognized keys: |
ce052c57 |
443 | |
81203272 |
444 | fun bar(:$size, @whatev) { ... } |
445 | |
446 | bar weight => 20, size => 2, location => [0, -3]; |
447 | # $size = 2, @whatev = ('weight', 20, 'location', [0, -3]) |
ce052c57 |
448 | |
81203272 |
449 | =back |
ce052c57 |
450 | |
81203272 |
451 | Apart from the L<C<shift>|perlfunc/shift> performed by the L<invocant|/"1. |
452 | Invocant">, all of the above leave L<C<@_>|perlvar/@ARG> unchanged; and if you |
453 | don't specify a parameter list at all, L<C<@_>|perlvar/@ARG> is all you get. |
d8e5d540 |
454 | |
81203272 |
455 | =head3 Keyword |
d8e5d540 |
456 | |
81203272 |
457 | The keywords provided by C<Function::Parameters> are customizable. Since |
458 | C<Function::Parameters> is actually a L<pragma|perlpragma>, the provided |
459 | keywords have lexical scope. The following import variants can be used: |
d8e5d540 |
460 | |
81203272 |
461 | =over |
273c6544 |
462 | |
81203272 |
463 | =item C<use Function::Parameters ':strict'> |
273c6544 |
464 | |
81203272 |
465 | Provides the keywords C<fun> and C<method> (described below) and enables |
466 | argument checks so that calling a function and omitting a required argument (or |
467 | passing too many arguments) will throw an error. |
273c6544 |
468 | |
81203272 |
469 | =item C<use Function::Parameters> |
273c6544 |
470 | |
81203272 |
471 | Provides the keywords C<fun> and C<method> (described below) and enables |
472 | "lax" mode: Omitting a required argument sets it to C<undef> while excess |
473 | arguments are silently ignored. |
273c6544 |
474 | |
81203272 |
475 | =item C<< use Function::Parameters { KEYWORD1 => TYPE1, KEYWORD2 => TYPE2, ... } >> |
698e861c |
476 | |
81203272 |
477 | Provides completely custom keywords as described by their types. A "type" is |
478 | either a string (one of the predefined types C<function>, C<method>, |
479 | C<classmethod>, C<function_strict>, C<method_strict>, C<classmethod_strict>) or |
480 | a reference to a hash with the following keys: |
698e861c |
481 | |
81203272 |
482 | =over |
698e861c |
483 | |
81203272 |
484 | =item C<name> |
698e861c |
485 | |
81203272 |
486 | Valid values: C<optional> (default), C<required> (all functions defined with |
487 | this keyword must have a name), and C<prohibited> (functions defined with this |
488 | keyword must be anonymous). |
698e861c |
489 | |
81203272 |
490 | =item C<shift> |
698e861c |
491 | |
81203272 |
492 | Valid values: strings that look like scalar variables. This lets you specify a |
493 | default L<invocant|/"1. Invocant">, i.e. a function defined with this keyword |
494 | that doesn't have an explicit invocant in its parameter list will automatically |
495 | L<C<shift>|perlfunc/shift> its first argument into the variable specified here. |
698e861c |
496 | |
81203272 |
497 | =item C<invocant> |
698e861c |
498 | |
81203272 |
499 | Valid values: booleans. If you set this to a true value, the keyword will |
500 | accept L<invocants|/"1. Invocant"> in parameter lists; otherwise specifying |
501 | an invocant in a function defined with this keyword is a syntax error. |
698e861c |
502 | |
81203272 |
503 | =item C<attributes> |
698e861c |
504 | |
81203272 |
505 | Valid values: strings containing (source code for) attributes. This causes any |
506 | function defined with this keyword to have the specified |
507 | L<attributes|attributes> (in addition to any attributes specified in the |
508 | function definition itself). |
698e861c |
509 | |
81203272 |
510 | =item C<default_arguments> |
698e861c |
511 | |
81203272 |
512 | Valid values: booleans. This property is on by default; use |
513 | C<< default_arguments => 0 >> to turn it off. This controls whether optional |
514 | parameters are allowed. If it is turned off, using C<=> in parameter lists is |
515 | a syntax error. |
698e861c |
516 | |
81203272 |
517 | =item C<check_argument_count> |
698e861c |
518 | |
81203272 |
519 | Valid values: booleans. If turned on, functions defined with this keyword will |
520 | automatically check that they have been passed all required arguments and no |
521 | excess arguments. If this check fails, an exception will by thrown via |
522 | L<C<Carp::croak>|Carp>. |
698e861c |
523 | |
ce052c57 |
524 | =back |
525 | |
81203272 |
526 | The predefined type C<function> is equivalent to: |
698e861c |
527 | |
528 | { |
529 | name => 'optional', |
81203272 |
530 | invocant => 0, |
698e861c |
531 | default_arguments => 1, |
532 | check_argument_count => 0, |
533 | } |
534 | |
81203272 |
535 | These are all default values, so C<function> is also equivalent to C<{}>. |
698e861c |
536 | |
81203272 |
537 | C<method> is equivalent to: |
698e861c |
538 | |
539 | { |
540 | name => 'optional', |
698e861c |
541 | shift => '$self', |
d8e5d540 |
542 | invocant => 1, |
81203272 |
543 | attributes => ':method', |
544 | default_arguments => 1, |
545 | check_argument_count => 0, |
698e861c |
546 | } |
547 | |
7817d698 |
548 | |
81203272 |
549 | C<classmethod> is equivalent to: |
698e861c |
550 | |
551 | { |
552 | name => 'optional', |
698e861c |
553 | shift => '$class', |
d8e5d540 |
554 | invocant => 1, |
81203272 |
555 | attributes => ':method', |
556 | default_arguments => 1, |
557 | check_argument_count => 0, |
698e861c |
558 | } |
ce052c57 |
559 | |
81203272 |
560 | C<function_strict>, C<method_strict>, and |
561 | C<classmethod_strict> are like C<function>, C<method>, and |
562 | C<classmethod>, respectively, but with C<< check_argument_count => 1 >>. |
63a24d7c |
563 | |
81203272 |
564 | =back |
63a24d7c |
565 | |
81203272 |
566 | Plain C<use Function::Parameters> is equivalent to |
567 | C<< use Function::Parameters { fun => 'function', method => 'method' } >>. |
63a24d7c |
568 | |
81203272 |
569 | C<use Function::Parameters qw(:strict)> is equivalent to |
570 | C<< use Function::Parameters { fun => 'function_strict', method => 'method_strict' } >>. |
63a24d7c |
571 | |
81203272 |
572 | =head2 Wrapping C<Function::Parameters> |
125c067e |
573 | |
81203272 |
574 | If you want to write a wrapper around C<Function::Parameters>, you only have to |
575 | call its C<import> method. Due to its L<pragma|perlpragma> nature it always |
576 | affects the file that is currently being compiled. |
63a24d7c |
577 | |
578 | package Some::Wrapper; |
579 | use Function::Parameters (); |
580 | sub import { |
581 | Function::Parameters->import; |
698e861c |
582 | # or Function::Parameters->import(@custom_import_args); |
63a24d7c |
583 | } |
eeb7df5f |
584 | |
81203272 |
585 | =head2 How it works |
586 | |
587 | The module is actually written in L<C|perlxs> and uses |
588 | L<C<PL_keyword_plugin>|perlapi/PL_keyword_plugin> to generate opcodes directly. |
589 | However, you can run L<C<perl -MO=Deparse ...>|B::Deparse> on your code to see |
590 | what happens under the hood. In the simplest case (no argument checks, possibly |
591 | an L<invocant|/"1. Invocant">, required positional/slurpy parameters only), the |
592 | generated code corresponds to: |
593 | |
594 | fun foo($x, $y, @z) { ... } |
595 | # ... turns into ... |
596 | sub foo { my ($x, $y, @z) = @_; sub foo; ... } |
597 | |
598 | method bar($x, $y, @z) { ... } |
599 | # ... turns into ... |
600 | sub bar :method { my $self = shift; my ($x, $y, @z) = @_; sub bar; ... } |
601 | |
7a63380c |
602 | =head1 AUTHOR |
603 | |
604 | Lukas Mai, C<< <l.mai at web.de> >> |
605 | |
606 | =head1 COPYRIGHT & LICENSE |
607 | |
db81d362 |
608 | Copyright 2010, 2011, 2012 Lukas Mai. |
7a63380c |
609 | |
610 | This program is free software; you can redistribute it and/or modify it |
611 | under the terms of either: the GNU General Public License as published |
612 | by the Free Software Foundation; or the Artistic License. |
613 | |
614 | See http://dev.perl.org/licenses/ for more information. |
615 | |
616 | =cut |