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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 Carp qw(confess); |
9 | |
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10 | use XSLoader; |
11 | BEGIN { |
1d143321 |
12 | our $VERSION = '0.06'; |
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13 | XSLoader::load; |
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14 | } |
15 | |
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16 | sub _assert_valid_identifier { |
17 | my ($name, $with_dollar) = @_; |
18 | my $bonus = $with_dollar ? '\$' : ''; |
19 | $name =~ /^${bonus}[^\W\d]\w*\z/ |
20 | or confess qq{"$name" doesn't look like a valid identifier}; |
21 | } |
22 | |
b72eb6ee |
23 | sub _assert_valid_attributes { |
24 | my ($attrs) = @_; |
25 | $attrs =~ /^\s*:\s*[^\W\d]\w*\s*(?:(?:\s|:\s*)[^\W\d]\w*\s*)*(?:\(|\z)/ |
26 | or confess qq{"$attrs" doesn't look like valid attributes}; |
27 | } |
28 | |
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29 | my @bare_arms = qw(function method); |
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30 | my %type_map = ( |
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31 | function => { |
32 | name => 'optional', |
33 | default_arguments => 1, |
34 | check_argument_count => 0, |
35 | }, |
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36 | method => { |
37 | name => 'optional', |
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38 | default_arguments => 1, |
39 | check_argument_count => 0, |
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40 | attrs => ':method', |
63915d26 |
41 | shift => '$self', |
7947f7ce |
42 | }, |
a23979e1 |
43 | classmethod => { |
44 | name => 'optional', |
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45 | default_arguments => 1, |
46 | check_argument_count => 0, |
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47 | attributes => ':method', |
63915d26 |
48 | shift => '$class', |
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49 | }, |
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50 | ); |
7817d698 |
51 | for my $k (keys %type_map) { |
52 | $type_map{$k . '_strict'} = { |
53 | %{$type_map{$k}}, |
54 | check_argument_count => 1, |
55 | }; |
56 | } |
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57 | |
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58 | sub import { |
59 | my $class = shift; |
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60 | |
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61 | @_ or @_ = { |
62 | fun => 'function', |
63 | method => 'method', |
64 | }; |
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65 | if (@_ == 1 && ref($_[0]) eq 'HASH') { |
66 | @_ = map [$_, $_[0]{$_}], keys %{$_[0]} |
67 | or return; |
68 | } |
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69 | |
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70 | my %spec; |
71 | |
72 | my $bare = 0; |
73 | for my $proto (@_) { |
74 | my $item = ref $proto |
75 | ? $proto |
76 | : [$proto, $bare_arms[$bare++] || confess(qq{Don't know what to do with "$proto"})] |
77 | ; |
ae6e00b5 |
78 | my ($name, $proto_type) = @$item; |
2d5cf47a |
79 | _assert_valid_identifier $name; |
80 | |
ae6e00b5 |
81 | unless (ref $proto_type) { |
82 | # use '||' instead of 'or' to preserve $proto_type in the error message |
83 | $proto_type = $type_map{$proto_type} |
84 | || confess qq["$proto_type" doesn't look like a valid type (one of ${\join ', ', sort keys %type_map})]; |
2d5cf47a |
85 | } |
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86 | |
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87 | my %type = %$proto_type; |
88 | my %clean; |
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89 | |
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90 | $clean{name} = delete $type{name} || 'optional'; |
91 | $clean{name} =~ /^(?:optional|required|prohibited)\z/ |
92 | or confess qq["$clean{name}" doesn't look like a valid name attribute (one of optional, required, prohibited)]; |
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93 | |
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94 | $clean{shift} = delete $type{shift} || ''; |
10acc8b1 |
95 | _assert_valid_identifier $clean{shift}, 1 if $clean{shift}; |
96 | |
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97 | $clean{attrs} = join ' ', map delete $type{$_} || (), qw(attributes attrs); |
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98 | _assert_valid_attributes $clean{attrs} if $clean{attrs}; |
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99 | |
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100 | $clean{default_arguments} = |
101 | exists $type{default_arguments} |
102 | ? !!delete $type{default_arguments} |
103 | : 1 |
104 | ; |
63915d26 |
105 | $clean{check_argument_count} = !!delete $type{check_argument_count}; |
106 | |
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107 | %type and confess "Invalid keyword property: @{[keys %type]}"; |
108 | |
109 | $spec{$name} = \%clean; |
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110 | } |
111 | |
db81d362 |
112 | for my $kw (keys %spec) { |
113 | my $type = $spec{$kw}; |
114 | |
63915d26 |
115 | my $flags = |
116 | $type->{name} eq 'prohibited' ? FLAG_ANON_OK : |
117 | $type->{name} eq 'required' ? FLAG_NAME_OK : |
118 | FLAG_ANON_OK | FLAG_NAME_OK |
119 | ; |
120 | $flags |= FLAG_DEFAULT_ARGS if $type->{default_arguments}; |
121 | $flags |= FLAG_CHECK_NARGS if $type->{check_argument_count}; |
122 | $^H{HINTK_FLAGS_ . $kw} = $flags; |
ae6e00b5 |
123 | $^H{HINTK_SHIFT_ . $kw} = $type->{shift}; |
10acc8b1 |
124 | $^H{HINTK_ATTRS_ . $kw} = $type->{attrs}; |
db81d362 |
125 | $^H{+HINTK_KEYWORDS} .= "$kw "; |
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126 | } |
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127 | } |
128 | |
db81d362 |
129 | sub unimport { |
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130 | my $class = shift; |
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131 | |
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132 | if (!@_) { |
133 | delete $^H{+HINTK_KEYWORDS}; |
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134 | return; |
135 | } |
136 | |
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137 | for my $kw (@_) { |
138 | $^H{+HINTK_KEYWORDS} =~ s/(?<![^ ])\Q$kw\E //g; |
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139 | } |
140 | } |
141 | |
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142 | |
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143 | 'ok' |
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144 | |
145 | __END__ |
146 | |
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147 | =encoding UTF-8 |
148 | |
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149 | =head1 NAME |
150 | |
151 | Function::Parameters - subroutine definitions with parameter lists |
152 | |
153 | =head1 SYNOPSIS |
154 | |
155 | use Function::Parameters; |
156 | |
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157 | # simple function |
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158 | fun foo($bar, $baz) { |
159 | return $bar + $baz; |
160 | } |
161 | |
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162 | # function with prototype |
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163 | fun mymap($fun, @args) :(&@) { |
164 | my @res; |
165 | for (@args) { |
166 | push @res, $fun->($_); |
167 | } |
168 | @res |
169 | } |
170 | |
171 | print "$_\n" for mymap { $_ * 2 } 1 .. 4; |
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172 | |
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173 | # method with implicit $self |
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174 | method set_name($name) { |
175 | $self->{name} = $name; |
176 | } |
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177 | |
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178 | # function with default arguments |
179 | fun search($haystack, $needle = qr/^(?!)/, $offset = 0) { |
180 | ... |
181 | } |
182 | |
183 | # method with default arguments |
184 | method skip($amount = 1) { |
185 | $self->{position} += $amount; |
186 | } |
187 | |
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188 | =cut |
189 | |
190 | =pod |
191 | |
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192 | # use different keywords |
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193 | use Function::Parameters { |
194 | proc => 'function', |
195 | meth => 'method', |
196 | }; |
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197 | |
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198 | my $f = proc ($x) { $x * 2 }; |
199 | meth get_age() { |
200 | return $self->{age}; |
201 | } |
202 | |
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203 | =head1 DESCRIPTION |
204 | |
205 | This module lets you use parameter lists in your subroutines. Thanks to |
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206 | L<PL_keyword_plugin|perlapi/PL_keyword_plugin> it works without source filters. |
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207 | |
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208 | WARNING: This is my first attempt at writing L<XS code|perlxs> and I have |
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209 | almost no experience with perl's internals. So while this module might |
210 | appear to work, it could also conceivably make your programs segfault. |
211 | Consider this module alpha quality. |
212 | |
213 | =head2 Basic stuff |
214 | |
215 | To use this new functionality, you have to use C<fun> instead of C<sub> - |
216 | C<sub> continues to work as before. The syntax is almost the same as for |
217 | C<sub>, but after the subroutine name (or directly after C<fun> if you're |
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218 | writing an anonymous sub) you can write a parameter list in parentheses. This |
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219 | list consists of comma-separated variables. |
220 | |
221 | The effect of C<fun foo($bar, $baz) {> is as if you'd written |
222 | C<sub foo { my ($bar, $baz) = @_; >, i.e. the parameter list is simply |
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223 | copied into L<my|perlfunc/my-EXPR> and initialized from L<@_|perlvar/"@_">. |
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224 | |
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225 | In addition you can use C<method>, which understands the same syntax as C<fun> |
226 | but automatically creates a C<$self> variable for you. So by writing |
227 | C<method foo($bar, $baz) {> you get the same effect as |
228 | C<sub foo { my $self = shift; my ($bar, $baz) = @_; >. |
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229 | |
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230 | =head2 Customizing the generated keywords |
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231 | |
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232 | You can customize the names of the keywords injected into your scope. To do |
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233 | that you pass a reference to a hash mapping keywords to types in the import |
234 | list: |
235 | |
236 | use Function::Parameters { |
237 | KEYWORD1 => TYPE1, |
238 | KEYWORD2 => TYPE2, |
239 | ... |
240 | }; |
241 | |
242 | Or more concretely: |
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243 | |
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244 | use Function::Parameters { proc => 'function', meth => 'method' }; # -or- |
245 | use Function::Parameters { proc => 'function' }; # -or- |
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246 | use Function::Parameters { meth => 'method' }; # etc. |
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247 | |
248 | The first line creates two keywords, C<proc> and C<meth> (for defining |
249 | functions and methods, respectively). The last two lines only create one |
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250 | keyword. Generally the hash keys (keywords) can be any identifiers you want |
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251 | while the values (types) have to be either a hash reference (see below) or |
252 | C<'function'>, C<'method'>, C<'classmethod'>, C<'function_strict'>, |
253 | C<'method_strict'>, or C<'classmethod_strict'>. The main difference between |
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254 | C<'function'> and C<'method'> is that C<'method'>s automatically |
255 | L<shift|perlfunc/shift> their first argument into C<$self> (C<'classmethod'>s |
256 | are similar but shift into C<$class>). |
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257 | |
258 | The following shortcuts are available: |
259 | |
260 | use Function::Parameters; |
261 | # is equivalent to # |
262 | use Function::Parameters { fun => 'function', method => 'method' }; |
263 | |
264 | =cut |
265 | |
266 | =pod |
267 | |
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268 | The following shortcuts are deprecated and may be removed from a future version |
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269 | of this module: |
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270 | |
271 | # DEPRECATED |
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272 | use Function::Parameters 'foo'; |
273 | # is equivalent to # |
274 | use Function::Parameters { 'foo' => 'function' }; |
275 | |
276 | =cut |
277 | |
278 | =pod |
279 | |
63a24d7c |
280 | # DEPRECATED |
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281 | use Function::Parameters 'foo', 'bar'; |
282 | # is equivalent to # |
283 | use Function::Parameters { 'foo' => 'function', 'bar' => 'method' }; |
284 | |
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285 | That is, if you want to pass arguments to L<Function::Parameters>, use a |
286 | hashref, not a list of strings. |
287 | |
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288 | You can customize the properties of the generated keywords even more by passing |
289 | a hashref instead of a string. This hash can have the following keys: |
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290 | |
291 | =over |
292 | |
293 | =item C<name> |
294 | |
295 | Valid values: C<optional> (default), C<required> (all uses of this keyword must |
296 | specify a function name), and C<prohibited> (all uses of this keyword must not |
297 | specify a function name). This means a C<< name => 'prohibited' >> keyword can |
298 | only be used for defining anonymous functions. |
299 | |
300 | =item C<shift> |
301 | |
302 | Valid values: strings that look like a scalar variable. Any function created by |
303 | this keyword will automatically L<shift|perlfunc/shift> its first argument into |
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304 | a local variable whose name is specified here. |
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305 | |
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306 | =item C<attributes>, C<attrs> |
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307 | |
308 | Valid values: strings that are valid source code for attributes. Any value |
309 | specified here will be inserted as a subroutine attribute in the generated |
310 | code. Thus: |
311 | |
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312 | use Function::Parameters { sub_l => { attributes => ':lvalue' } }; |
273c6544 |
313 | sub_l foo() { |
314 | ... |
315 | } |
316 | |
317 | turns into |
318 | |
319 | sub foo :lvalue { |
320 | ... |
321 | } |
322 | |
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323 | It is recommended that you use C<attributes> in new code but C<attrs> is also |
324 | accepted for now. |
325 | |
326 | =item C<default_arguments> |
327 | |
328 | Valid values: booleans. This property is on by default, so you have to pass |
329 | C<< default_arguments => 0 >> to turn it off. If it is disabled, using C<=> in |
330 | a parameter list causes a syntax error. Otherwise it lets you specify |
331 | default arguments directly in the parameter list: |
332 | |
333 | fun foo($x, $y = 42, $z = []) { |
334 | ... |
335 | } |
336 | |
337 | turns into |
338 | |
339 | sub foo { |
340 | my ($x, $y, $z) = @_; |
341 | $y = 42 if @_ < 2; |
342 | $z = [] if @_ < 3; |
343 | ... |
344 | } |
345 | |
1e0f1595 |
346 | You can even refer to previous parameters in the same parameter list: |
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347 | |
1e0f1595 |
348 | print fun ($x, $y = $x + 1) { "$x and $y" }->(9); # "9 and 10" |
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349 | |
1e0f1595 |
350 | This also works with the implicit first parameter of methods: |
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351 | |
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352 | method scale($factor = $self->default_factor) { |
353 | $self->{amount} *= $factor; |
354 | } |
698e861c |
355 | |
356 | =item C<check_argument_count> |
357 | |
358 | Valid values: booleans. This property is off by default. If it is enabled, the |
359 | generated code will include checks to make sure the number of passed arguments |
360 | is correct (and otherwise throw an exception via L<Carp::croak|Carp>): |
361 | |
362 | fun foo($x, $y = 42, $z = []) { |
363 | ... |
364 | } |
365 | |
366 | turns into |
367 | |
368 | sub foo { |
369 | Carp::croak "Not enough arguments for fun foo" if @_ < 1; |
370 | Carp::croak "Too many arguments for fun foo" if @_ > 3; |
371 | my ($x, $y, $z) = @_; |
372 | $y = 42 if @_ < 2; |
373 | $z = [] if @_ < 3; |
374 | ... |
375 | } |
376 | |
ce052c57 |
377 | =back |
378 | |
698e861c |
379 | Plain C<'function'> is equivalent to: |
380 | |
381 | { |
382 | name => 'optional', |
383 | default_arguments => 1, |
384 | check_argument_count => 0, |
385 | } |
386 | |
387 | (These are all default values so C<'function'> is also equivalent to C<{}>.) |
388 | |
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389 | C<'function_strict'> is like C<'function'> but with |
390 | C<< check_argument_count => 1 >>. |
391 | |
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392 | C<'method'> is equivalent to: |
393 | |
394 | { |
395 | name => 'optional', |
396 | default_arguments => 1, |
397 | check_argument_count => 0, |
398 | attributes => ':method', |
399 | shift => '$self', |
400 | } |
401 | |
7817d698 |
402 | C<'method_strict'> is like C<'method'> but with |
403 | C<< check_argument_count => 1 >>. |
404 | |
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405 | C<'classmethod'> is equivalent to: |
406 | |
407 | { |
408 | name => 'optional', |
409 | default_arguments => 1, |
410 | check_argument_count => 0, |
411 | attributes => ':method', |
412 | shift => '$class', |
413 | } |
ce052c57 |
414 | |
7817d698 |
415 | C<'classmethod_strict'> is like C<'classmethod'> but with |
416 | C<< check_argument_count => 1 >>. |
417 | |
63a24d7c |
418 | =head2 Syntax and generated code |
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419 | |
420 | Normally, Perl subroutines are not in scope in their own body, meaning the |
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421 | parser doesn't know the name C<foo> or its prototype while processing the body |
422 | of C<sub foo ($) { foo $bar[1], $bar[0]; }>, parsing it as |
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423 | C<$bar-E<gt>foo([1], $bar[0])>. Yes. You can add parens to change the |
424 | interpretation of this code, but C<foo($bar[1], $bar[0])> will only trigger |
425 | a I<foo() called too early to check prototype> warning. This module attempts |
698e861c |
426 | to fix all of this by adding a subroutine declaration before the function body, |
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427 | so the parser knows the name (and possibly prototype) while it processes the |
428 | body. Thus C<fun foo($x) :($) { $x }> really turns into |
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429 | C<sub foo ($) { sub foo ($); my ($x) = @_; $x }>. |
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430 | |
95915793 |
431 | If you need L<subroutine attributes|perlsub/Subroutine-Attributes>, you can |
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432 | put them after the parameter list with their usual syntax. |
433 | |
434 | Syntactically, these new parameter lists live in the spot normally occupied |
435 | by L<prototypes|perlsub/"Prototypes">. However, you can include a prototype by |
436 | specifying it as the first attribute (this is syntactically unambiguous |
63a24d7c |
437 | because normal attributes have to start with a letter while a prototype starts |
438 | with C<(>). |
439 | |
698e861c |
440 | As an example, the following declaration uses every available feature |
441 | (subroutine name, parameter list, default arguments, prototype, default |
442 | attributes, attributes, argument count checks, and implicit C<$self>): |
63a24d7c |
443 | |
698e861c |
444 | method foo($x, $y, $z = sqrt 5) :($$$;$) :lvalue :Banana(2 + 2) { |
63a24d7c |
445 | ... |
446 | } |
447 | |
448 | And here's what it turns into: |
449 | |
698e861c |
450 | sub foo ($$$;$) :method :lvalue :Banana(2 + 2) { |
451 | sub foo ($$$;$); |
452 | Carp::croak "Not enough arguments for method foo" if @_ < 2; |
453 | Carp::croak "Too many arguments for method foo" if @_ > 4; |
454 | my $self = shift; |
455 | my ($x, $y, $z) = @_; |
456 | $z = sqrt 5 if @_ < 3; |
63a24d7c |
457 | ... |
458 | } |
459 | |
460 | Another example: |
461 | |
462 | my $coderef = fun ($p, $q) :(;$$) |
463 | :lvalue |
464 | :Gazebo((>:O)) { |
465 | ... |
466 | }; |
467 | |
468 | And the generated code: |
469 | |
698e861c |
470 | my $coderef = sub (;$$) :lvalue :Gazebo((>:O)) { |
471 | # vvv only if check_argument_count is enabled vvv |
472 | Carp::croak "Not enough arguments for fun (anon)" if @_ < 2; |
473 | Carp::croak "Too many arguments for fun (anon)" if @_ > 2; |
7817d698 |
474 | # ^^^ ^^^ |
698e861c |
475 | my ($p, $q) = @_; |
63a24d7c |
476 | ... |
477 | }; |
478 | |
479 | =head2 Wrapping Function::Parameters |
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480 | |
db81d362 |
481 | If you want to wrap L<Function::Parameters>, you just have to call its |
482 | C<import> method. It always applies to the file that is currently being parsed |
95915793 |
483 | and its effects are L<lexical|perlpragma> (i.e. it works like L<warnings> or |
484 | L<strict>). |
63a24d7c |
485 | |
486 | package Some::Wrapper; |
487 | use Function::Parameters (); |
488 | sub import { |
489 | Function::Parameters->import; |
698e861c |
490 | # or Function::Parameters->import(@custom_import_args); |
63a24d7c |
491 | } |
eeb7df5f |
492 | |
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493 | =head1 AUTHOR |
494 | |
495 | Lukas Mai, C<< <l.mai at web.de> >> |
496 | |
497 | =head1 COPYRIGHT & LICENSE |
498 | |
db81d362 |
499 | Copyright 2010, 2011, 2012 Lukas Mai. |
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500 | |
501 | This program is free software; you can redistribute it and/or modify it |
502 | under the terms of either: the GNU General Public License as published |
503 | by the Free Software Foundation; or the Artistic License. |
504 | |
505 | See http://dev.perl.org/licenses/ for more information. |
506 | |
507 | =cut |