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1 | package Sub::Quote; |
2 | |
3 | use strictures 1; |
4 | |
5 | sub _clean_eval { eval $_[0] } |
6 | |
7 | use Sub::Defer; |
8 | use B 'perlstring'; |
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9 | use Scalar::Util qw(weaken); |
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10 | use base qw(Exporter); |
11 | |
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12 | our @EXPORT = qw(quote_sub unquote_sub quoted_from_sub); |
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13 | |
14 | our %QUOTE_OUTSTANDING; |
15 | |
16 | our %QUOTED; |
17 | |
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18 | our %WEAK_REFS; |
19 | |
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20 | sub capture_unroll { |
21 | my ($from, $captures, $indent) = @_; |
22 | join( |
23 | '', |
24 | map { |
25 | /^([\@\%\$])/ |
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26 | or die "capture key should start with \@, \% or \$: $_"; |
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27 | (' ' x $indent).qq{my ${_} = ${1}{${from}->{${\perlstring $_}}};\n}; |
28 | } keys %$captures |
29 | ); |
30 | } |
31 | |
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32 | sub inlinify { |
33 | my ($code, $args, $extra, $local) = @_; |
34 | my $do = 'do { '.($extra||''); |
35 | if (my ($code_args, $body) = $code =~ / +my \(([^)]+)\) = \@_;(.*)$/s) { |
36 | if ($code_args eq $args) { |
37 | $do.$body.' }' |
38 | } else { |
f537c364 |
39 | $do.'my ('.$code_args.') = ('.$args.'); '.$body.' }'; |
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40 | } |
41 | } else { |
42 | $do.($local ? 'local ' : '').'@_ = ('.$args.'); '.$code.' }'; |
43 | } |
44 | } |
45 | |
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46 | sub _unquote_all_outstanding { |
47 | return unless %QUOTE_OUTSTANDING; |
48 | my ($assembled_code, @assembled_captures, @localize_these) = ''; |
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49 | # we sort the keys in order to make debugging more predictable |
50 | foreach my $outstanding (sort keys %QUOTE_OUTSTANDING) { |
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51 | my ($name, $code, $captures) = @{$QUOTE_OUTSTANDING{$outstanding}}; |
52 | |
53 | push @localize_these, $name if $name; |
54 | |
55 | my $make_sub = "{\n"; |
56 | |
57 | if (keys %$captures) { |
58 | my $ass_cap_count = @assembled_captures; |
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59 | $make_sub .= capture_unroll("\$_[1][${ass_cap_count}]", $captures, 2); |
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60 | push @assembled_captures, $captures; |
61 | } |
62 | |
63 | my $o_quoted = perlstring $outstanding; |
64 | $make_sub .= ( |
65 | $name |
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66 | # disable the 'variable $x will not stay shared' warning since |
67 | # we're not letting it escape from this scope anyway so there's |
68 | # nothing trying to share it |
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69 | ? " no warnings 'closure';\n sub ${name} {\n" |
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70 | : " \$Sub::Quote::QUOTED{${o_quoted}}[3] = sub {\n" |
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71 | ); |
72 | $make_sub .= $code; |
73 | $make_sub .= " }".($name ? '' : ';')."\n"; |
74 | if ($name) { |
75 | $make_sub .= " \$Sub::Quote::QUOTED{${o_quoted}}[3] = \\&${name}\n"; |
76 | } |
77 | $make_sub .= "}\n"; |
78 | $assembled_code .= $make_sub; |
79 | } |
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80 | my $debug_code = $assembled_code; |
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81 | if (@localize_these) { |
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82 | $debug_code = |
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83 | "# localizing: ".join(', ', @localize_these)."\n" |
84 | .$assembled_code; |
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85 | $assembled_code = join("\n", |
86 | (map { "local *${_};" } @localize_these), |
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87 | 'eval '.perlstring($assembled_code).'; die $@ if $@;' |
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88 | ); |
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89 | } else { |
90 | $ENV{SUB_QUOTE_DEBUG} && warn $assembled_code; |
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91 | } |
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92 | $assembled_code .= "\n1;"; |
93 | unless (_clean_eval $assembled_code, \@assembled_captures) { |
94 | die "Eval went very, very wrong:\n\n${debug_code}\n\n$@"; |
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95 | } |
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96 | $ENV{SUB_QUOTE_DEBUG} && warn $debug_code; |
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97 | %QUOTE_OUTSTANDING = (); |
98 | } |
99 | |
100 | sub quote_sub { |
101 | # HOLY DWIMMERY, BATMAN! |
6f68f022 |
102 | # $name => $code => \%captures => \%options |
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103 | # $name => $code => \%captures |
104 | # $name => $code |
6f68f022 |
105 | # $code => \%captures => \%options |
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106 | # $code |
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107 | my $options = |
108 | (ref($_[-1]) eq 'HASH' and ref($_[-2]) eq 'HASH') |
109 | ? pop |
110 | : {}; |
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111 | my $captures = pop if ref($_[-1]) eq 'HASH'; |
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112 | undef($captures) if $captures && !keys %$captures; |
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113 | my $code = pop; |
114 | my $name = $_[0]; |
115 | my $outstanding; |
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116 | my $deferred = defer_sub +($options->{no_install} ? undef : $name) => sub { |
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117 | unquote_sub($outstanding); |
118 | }; |
119 | $outstanding = "$deferred"; |
120 | $QUOTE_OUTSTANDING{$outstanding} = $QUOTED{$outstanding} = [ |
121 | $name, $code, $captures |
122 | ]; |
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123 | weaken($WEAK_REFS{$outstanding} = $deferred); |
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124 | return $deferred; |
125 | } |
126 | |
127 | sub quoted_from_sub { |
128 | my ($sub) = @_; |
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129 | $WEAK_REFS{$sub||''} and $QUOTED{$sub||''}; |
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130 | } |
131 | |
132 | sub unquote_sub { |
133 | my ($sub) = @_; |
134 | _unquote_all_outstanding; |
135 | $QUOTED{$sub}[3]; |
136 | } |
137 | |
138 | 1; |
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139 | |
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140 | =head1 NAME |
141 | |
142 | Sub::Quote - efficient generation of subroutines via string eval |
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143 | |
144 | =head1 SYNOPSIS |
145 | |
146 | package Silly; |
147 | |
148 | use Sub::Quote qw(quote_sub unquote_sub quoted_from_sub); |
149 | |
150 | quote_sub 'Silly::kitty', q{ print "meow" }; |
151 | |
152 | quote_sub 'Silly::doggy', q{ print "woof" }; |
153 | |
154 | my $sound; $$sound = 0; |
155 | |
156 | quote_sub 'Silly::dagron', |
157 | q{ print ++$$sound % 2 ? 'burninate' : 'roar' }, |
158 | { '$sound' => \$sound }; |
159 | |
160 | And elsewhere: |
161 | |
162 | Silly->kitty; # meow |
163 | Silly->doggy; # woof |
164 | Silly->dagron; # burninate |
165 | Silly->dagron; # roar |
166 | Silly->dagron; # burninate |
167 | |
168 | =head1 DESCRIPTION |
169 | |
170 | This package provides performant ways to generate subroutines from strings. |
171 | |
172 | =head1 SUBROUTINES |
173 | |
174 | =head2 quote_sub |
175 | |
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176 | my $coderef = quote_sub 'Foo::bar', q{ print $x++ . "\n" }, { '$x' => \0 }; |
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177 | |
178 | Arguments: ?$name, $code, ?\%captures, ?\%options |
179 | |
180 | C<$name> is the subroutine where the coderef will be installed. |
181 | |
182 | C<$code> is a string that will be turned into code. |
183 | |
184 | C<\%captures> is a hashref of variables that will be made available to the |
185 | code. See the L</SYNOPSIS>'s C<Silly::dagron> for an example using captures. |
186 | |
187 | =head3 options |
188 | |
189 | =over 2 |
190 | |
191 | =item * no_install |
192 | |
193 | B<Boolean>. Set this option to not install the generated coderef into the |
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194 | passed subroutine name on undefer. |
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195 | |
196 | =back |
197 | |
198 | =head2 unquote_sub |
199 | |
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200 | my $coderef = unquote_sub $sub; |
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201 | |
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202 | Forcibly replace subroutine with actual code. Note that for performance |
203 | reasons all quoted subs declared so far will be globally unquoted/parsed in |
204 | a single eval. This means that if you have a syntax error in one of your |
205 | quoted subs you may find out when some other sub is unquoted. |
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206 | |
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207 | If $sub is not a quoted sub, this is a no-op. |
208 | |
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209 | =head2 quoted_from_sub |
210 | |
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211 | my $data = quoted_from_sub $sub; |
212 | |
213 | my ($name, $code, $captures, $compiled_sub) = @$data; |
214 | |
215 | Returns original arguments to quote_sub, plus the compiled version if this |
216 | sub has already been unquoted. |
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217 | |
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218 | Note that $sub can be either the original quoted version or the compiled |
219 | version for convenience. |
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220 | |
221 | =head2 inlinify |
222 | |
223 | my $prelude = capture_unroll { |
224 | '$x' => 1, |
225 | '$y' => 2, |
226 | }; |
227 | |
228 | my $inlined_code = inlinify q{ |
229 | my ($x, $y) = @_; |
230 | |
231 | print $x + $y . "\n"; |
232 | }, '$x, $y', $prelude; |
233 | |
234 | Takes a string of code, a string of arguments, a string of code which acts as a |
235 | "prelude", and a B<Boolean> representing whether or not to localize the |
236 | arguments. |
237 | |
238 | =head2 capture_unroll |
239 | |
240 | my $prelude = capture_unroll { |
241 | '$x' => 1, |
242 | '$y' => 2, |
243 | }; |
244 | |
245 | Generates a snippet of code which is suitable to be used as a prelude for |
246 | L</inlinify>. The keys are the names of the variables and the values are (duh) |
247 | the values. Note that references work as values. |