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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 $VERSION = '0.05_02'; |
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11 | XSLoader::load; |
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12 | } |
13 | |
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14 | use B::Hooks::EndOfScope qw(on_scope_end); |
15 | use Carp qw(confess); |
16 | use bytes (); |
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17 | |
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18 | sub _assert_valid_identifier { |
19 | my ($name, $with_dollar) = @_; |
20 | my $bonus = $with_dollar ? '\$' : ''; |
21 | $name =~ /^${bonus}[^\W\d]\w*\z/ |
22 | or confess qq{"$name" doesn't look like a valid identifier}; |
23 | } |
24 | |
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25 | my @bare_arms = qw(function method); |
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26 | my %type_map = ( |
27 | function => { name => 'optional' }, |
28 | method => { name => 'optional', shift => '$self' }, |
29 | ); |
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30 | |
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31 | sub import { |
32 | my $class = shift; |
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33 | |
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34 | @_ or @_ = ('fun', 'method'); |
35 | if (@_ == 1 && ref($_[0]) eq 'HASH') { |
36 | @_ = map [$_, $_[0]{$_}], keys %{$_[0]} |
37 | or return; |
38 | } |
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39 | |
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40 | my %spec; |
41 | |
42 | my $bare = 0; |
43 | for my $proto (@_) { |
44 | my $item = ref $proto |
45 | ? $proto |
46 | : [$proto, $bare_arms[$bare++] || confess(qq{Don't know what to do with "$proto"})] |
47 | ; |
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48 | my ($name, $proto_type) = @$item; |
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49 | _assert_valid_identifier $name; |
50 | |
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51 | unless (ref $proto_type) { |
52 | # use '||' instead of 'or' to preserve $proto_type in the error message |
53 | $proto_type = $type_map{$proto_type} |
54 | || confess qq["$proto_type" doesn't look like a valid type (one of ${\join ', ', sort keys %type_map})]; |
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55 | } |
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56 | my %type = %$proto_type; |
57 | my %clean; |
58 | $clean{name} = delete $type{name} || 'optional'; |
59 | $clean{name} =~ /^(?:optional|required|prohibited)\z/ |
60 | or confess qq["$clean{name}" doesn't look like a valid name attribute (one of optional, required, prohibited)]; |
61 | $clean{shift} = delete $type{shift} || ''; |
62 | if ($clean{shift}) { |
63 | _assert_valid_identifier $clean{shift}, 1; |
64 | bytes::length($clean{shift}) < SHIFT_NAME_LIMIT |
65 | or confess qq["$clean{shift}" is longer than I can handle]; |
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66 | } |
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67 | |
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68 | %type and confess "Invalid keyword property: @{[keys %type]}"; |
69 | |
70 | $spec{$name} = \%clean; |
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71 | } |
72 | |
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73 | for my $kw (keys %spec) { |
74 | my $type = $spec{$kw}; |
75 | |
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76 | $^H{HINTK_SHIFT_ . $kw} = $type->{shift}; |
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77 | $^H{HINTK_NAME_ . $kw} = |
78 | $type->{name} eq 'prohibited' ? FLAG_NAME_PROHIBITED : |
79 | $type->{name} eq 'required' ? FLAG_NAME_REQUIRED : |
80 | FLAG_NAME_OPTIONAL |
81 | ; |
82 | $^H{+HINTK_KEYWORDS} .= "$kw "; |
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83 | } |
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84 | } |
85 | |
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86 | sub unimport { |
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87 | my $class = shift; |
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88 | |
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89 | if (!@_) { |
90 | delete $^H{+HINTK_KEYWORDS}; |
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91 | return; |
92 | } |
93 | |
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94 | for my $kw (@_) { |
95 | $^H{+HINTK_KEYWORDS} =~ s/(?<![^ ])\Q$kw\E //g; |
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96 | } |
97 | } |
98 | |
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99 | sub _fini { |
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100 | on_scope_end { |
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101 | xs_fini; |
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102 | }; |
103 | } |
104 | |
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105 | |
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106 | 'ok' |
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107 | |
108 | __END__ |
109 | |
110 | =head1 NAME |
111 | |
112 | Function::Parameters - subroutine definitions with parameter lists |
113 | |
114 | =head1 SYNOPSIS |
115 | |
116 | use Function::Parameters; |
117 | |
118 | fun foo($bar, $baz) { |
119 | return $bar + $baz; |
120 | } |
121 | |
122 | fun mymap($fun, @args) :(&@) { |
123 | my @res; |
124 | for (@args) { |
125 | push @res, $fun->($_); |
126 | } |
127 | @res |
128 | } |
129 | |
130 | print "$_\n" for mymap { $_ * 2 } 1 .. 4; |
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131 | |
132 | method set_name($name) { |
133 | $self->{name} = $name; |
134 | } |
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135 | |
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136 | =cut |
137 | |
138 | =pod |
139 | |
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140 | use Function::Parameters { |
141 | proc => 'function', |
142 | meth => 'method', |
143 | }; |
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144 | |
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145 | my $f = proc ($x) { $x * 2 }; |
146 | meth get_age() { |
147 | return $self->{age}; |
148 | } |
149 | |
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150 | =head1 DESCRIPTION |
151 | |
152 | This module lets you use parameter lists in your subroutines. Thanks to |
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153 | L<PL_keyword_plugin|perlapi/PL_keyword_plugin> it works without source filters. |
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154 | |
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155 | WARNING: This is my first attempt at writing L<XS code|perlxs> and I have |
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156 | almost no experience with perl's internals. So while this module might |
157 | appear to work, it could also conceivably make your programs segfault. |
158 | Consider this module alpha quality. |
159 | |
160 | =head2 Basic stuff |
161 | |
162 | To use this new functionality, you have to use C<fun> instead of C<sub> - |
163 | C<sub> continues to work as before. The syntax is almost the same as for |
164 | C<sub>, but after the subroutine name (or directly after C<fun> if you're |
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165 | writing an anonymous sub) you can write a parameter list in parentheses. This |
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166 | list consists of comma-separated variables. |
167 | |
168 | The effect of C<fun foo($bar, $baz) {> is as if you'd written |
169 | C<sub foo { my ($bar, $baz) = @_; >, i.e. the parameter list is simply |
170 | copied into C<my> and initialized from L<@_|perlvar/"@_">. |
171 | |
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172 | In addition you can use C<method>, which understands the same syntax as C<fun> |
173 | but automatically creates a C<$self> variable for you. So by writing |
174 | C<method foo($bar, $baz) {> you get the same effect as |
175 | C<sub foo { my $self = shift; my ($bar, $baz) = @_; >. |
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176 | |
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177 | =head2 Customizing the generated keywords |
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178 | |
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179 | You can customize the names of the keywords injected into your scope. To do |
180 | that you pass a hash reference in the import list: |
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181 | |
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182 | use Function::Parameters { proc => 'function', meth => 'method' }; # -or- |
183 | use Function::Parameters { proc => 'function' }; # -or- |
184 | use Function::Parameters { meth => 'method' }; |
185 | |
186 | The first line creates two keywords, C<proc> and C<meth> (for defining |
187 | functions and methods, respectively). The last two lines only create one |
188 | keyword. Generally the hash keys can be any identifiers you want while the |
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189 | values have to be either C<function>, C<method>, or a hash reference (see |
190 | below). The difference between C<function> and C<method> is that C<method>s |
191 | automatically L<shift|perlfunc/shift> their first argument into C<$self>. |
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192 | |
193 | The following shortcuts are available: |
194 | |
195 | use Function::Parameters; |
196 | # is equivalent to # |
197 | use Function::Parameters { fun => 'function', method => 'method' }; |
198 | |
199 | =cut |
200 | |
201 | =pod |
202 | |
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203 | The following shortcuts are deprecated and may be removed from a future version |
204 | of the module: |
205 | |
206 | # DEPRECATED |
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207 | use Function::Parameters 'foo'; |
208 | # is equivalent to # |
209 | use Function::Parameters { 'foo' => 'function' }; |
210 | |
211 | =cut |
212 | |
213 | =pod |
214 | |
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215 | # DEPRECATED |
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216 | use Function::Parameters 'foo', 'bar'; |
217 | # is equivalent to # |
218 | use Function::Parameters { 'foo' => 'function', 'bar' => 'method' }; |
219 | |
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220 | That is, if you want to pass arguments to L<Function::Parameters>, use a |
221 | hashref, not a list of strings. |
222 | |
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223 | You can customize things even more by passing a hashref instead of C<function> |
224 | or C<method>. This hash can have the following keys: |
225 | |
226 | =over |
227 | |
228 | =item C<name> |
229 | |
230 | Valid values: C<optional> (default), C<required> (all uses of this keyword must |
231 | specify a function name), and C<prohibited> (all uses of this keyword must not |
232 | specify a function name). This means a C<< name => 'prohibited' >> keyword can |
233 | only be used for defining anonymous functions. |
234 | |
235 | =item C<shift> |
236 | |
237 | Valid values: strings that look like a scalar variable. Any function created by |
238 | this keyword will automatically L<shift|perlfunc/shift> its first argument into |
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239 | a local variable whose name is specified here. |
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240 | |
241 | =back |
242 | |
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243 | Plain C<'function'> is equivalent to C<< { name => 'optional' } >>, and plain |
244 | C<'method'> is equivalent to C<< { name => 'optional', shift => '$self' } >>. |
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245 | |
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246 | =head2 Syntax and generated code |
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247 | |
248 | Normally, Perl subroutines are not in scope in their own body, meaning the |
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249 | parser doesn't know the name C<foo> or its prototype while processing the body |
250 | of C<sub foo ($) { foo $bar[1], $bar[0]; }>, parsing it as |
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251 | C<$bar-E<gt>foo([1], $bar[0])>. Yes. You can add parens to change the |
252 | interpretation of this code, but C<foo($bar[1], $bar[0])> will only trigger |
253 | a I<foo() called too early to check prototype> warning. This module attempts |
254 | to fix all of this by adding a subroutine declaration before the definition, |
255 | so the parser knows the name (and possibly prototype) while it processes the |
256 | body. Thus C<fun foo($x) :($) { $x }> really turns into |
257 | C<sub foo ($); sub foo ($) { my ($x) = @_; $x }>. |
258 | |
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259 | If you need L<subroutine attributes|perlsub/"Subroutine Attributes">, you can |
260 | put them after the parameter list with their usual syntax. |
261 | |
262 | Syntactically, these new parameter lists live in the spot normally occupied |
263 | by L<prototypes|perlsub/"Prototypes">. However, you can include a prototype by |
264 | specifying it as the first attribute (this is syntactically unambiguous |
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265 | because normal attributes have to start with a letter while a prototype starts |
266 | with C<(>). |
267 | |
268 | As an example, the following declaration uses every feature available |
269 | (subroutine name, parameter list, prototype, attributes, and implicit |
270 | C<$self>): |
271 | |
272 | method foo($x, $y, @z) :($;$@) :lvalue :Banana(2 + 2) { |
273 | ... |
274 | } |
275 | |
276 | And here's what it turns into: |
277 | |
278 | sub foo ($;$@); sub foo ($;$@) :lvalue :Banana(2 + 2) { my $self = shift; my ($x, $y, @z) = @_; |
279 | ... |
280 | } |
281 | |
282 | Another example: |
283 | |
284 | my $coderef = fun ($p, $q) :(;$$) |
285 | :lvalue |
286 | :Gazebo((>:O)) { |
287 | ... |
288 | }; |
289 | |
290 | And the generated code: |
291 | |
292 | my $coderef = sub (;$$) :lvalue :Gazebo((>:O)) { my ($p, $q) = @_; |
293 | ... |
294 | }; |
295 | |
296 | =head2 Wrapping Function::Parameters |
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297 | |
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298 | If you want to wrap L<Function::Parameters>, you just have to call its |
299 | C<import> method. It always applies to the file that is currently being parsed |
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300 | and its effects are lexical (i.e. it works like L<warnings> or L<strict>): |
301 | |
302 | package Some::Wrapper; |
303 | use Function::Parameters (); |
304 | sub import { |
305 | Function::Parameters->import; |
306 | # or Function::Parameters->import(@other_import_args); |
307 | } |
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308 | |
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309 | =head1 AUTHOR |
310 | |
311 | Lukas Mai, C<< <l.mai at web.de> >> |
312 | |
313 | =head1 COPYRIGHT & LICENSE |
314 | |
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315 | Copyright 2010, 2011, 2012 Lukas Mai. |
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316 | |
317 | This program is free software; you can redistribute it and/or modify it |
318 | under the terms of either: the GNU General Public License as published |
319 | by the Free Software Foundation; or the Artistic License. |
320 | |
321 | See http://dev.perl.org/licenses/ for more information. |
322 | |
323 | =cut |