Commit | Line | Data |
3176feef |
1 | package Try::Tiny; |
12b7dc6c |
2 | use 5.006; |
3 | # ABSTRACT: minimal try/catch with proper preservation of $@ |
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4 | |
5 | use strict; |
f9d19a00 |
6 | use warnings; |
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7 | |
f9d19a00 |
8 | use base 'Exporter'; |
9 | our @EXPORT = our @EXPORT_OK = qw(try catch finally); |
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10 | |
f9d19a00 |
11 | use Carp; |
6f114080 |
12 | $Carp::Internal{+__PACKAGE__}++; |
13 | |
5c9d800f |
14 | BEGIN { eval "use Sub::Name; 1" or *{subname} = sub {1} } |
15 | |
7195fc08 |
16 | # Need to prototype as @ not $$ because of the way Perl evaluates the prototype. |
17 | # Keeping it at $$ means you only ever get 1 sub because we need to eval in a list |
18 | # context & not a scalar one |
19 | |
20 | sub try (&;@) { |
8d2ee831 |
21 | my ( $try, @code_refs ) = @_; |
22 | |
23 | # we need to save this here, the eval block will be in scalar context due |
24 | # to $failed |
25 | my $wantarray = wantarray; |
26 | |
27 | my ( $catch, @finally ); |
28 | |
29 | # find labeled blocks in the argument list. |
30 | # catch and finally tag the blocks by blessing a scalar reference to them. |
31 | foreach my $code_ref (@code_refs) { |
8d2ee831 |
32 | |
4c5b99d6 |
33 | if ( ref($code_ref) eq 'Try::Tiny::Catch' ) { |
9d0e0466 |
34 | croak 'A try() may not be followed by multiple catch() blocks' |
35 | if $catch; |
8d2ee831 |
36 | $catch = ${$code_ref}; |
4c5b99d6 |
37 | } elsif ( ref($code_ref) eq 'Try::Tiny::Finally' ) { |
8d2ee831 |
38 | push @finally, ${$code_ref}; |
39 | } else { |
4c5b99d6 |
40 | croak( |
41 | 'try() encountered an unexpected argument (' |
42 | . ( defined $code_ref ? $code_ref : 'undef' ) |
43 | . ') - perhaps a missing semi-colon before or' |
44 | ); |
8d2ee831 |
45 | } |
46 | } |
47 | |
2b0d579d |
48 | # FIXME consider using local $SIG{__DIE__} to accumulate all errors. It's |
49 | # not perfect, but we could provide a list of additional errors for |
50 | # $catch->(); |
51 | |
5c9d800f |
52 | # name the blocks if we have Sub::Name installed |
1131a831 |
53 | my $caller = caller; |
faa955ce |
54 | subname("${caller}::try {...} " => $try); |
1131a831 |
55 | subname("${caller}::catch {...} " => $catch) if $catch; |
56 | subname("${caller}::finally {...} " => $_) foreach @finally; |
5c9d800f |
57 | |
8d2ee831 |
58 | # save the value of $@ so we can set $@ back to it in the beginning of the eval |
2b0d579d |
59 | # and restore $@ after the eval finishes |
8d2ee831 |
60 | my $prev_error = $@; |
61 | |
2b0d579d |
62 | my ( @ret, $error ); |
8d2ee831 |
63 | |
2b0d579d |
64 | # failed will be true if the eval dies, because 1 will not be returned |
65 | # from the eval body |
66 | my $failed = not eval { |
67 | $@ = $prev_error; |
8d2ee831 |
68 | |
2b0d579d |
69 | # evaluate the try block in the correct context |
70 | if ( $wantarray ) { |
71 | @ret = $try->(); |
72 | } elsif ( defined $wantarray ) { |
73 | $ret[0] = $try->(); |
74 | } else { |
75 | $try->(); |
8d2ee831 |
76 | }; |
77 | |
2b0d579d |
78 | return 1; # properly set $fail to false |
3db0dca6 |
79 | }; |
2b0d579d |
80 | |
3db0dca6 |
81 | # preserve the current error and reset the original value of $@ |
82 | $error = $@; |
2b0d579d |
83 | $@ = $prev_error; |
8d2ee831 |
84 | |
85 | # set up a scope guard to invoke the finally block at the end |
86 | my @guards = |
b611f396 |
87 | map { Try::Tiny::ScopeGuard->_new($_, $failed ? $error : ()) } |
88 | @finally; |
82ef0e61 |
89 | |
8d2ee831 |
90 | # at this point $failed contains a true value if the eval died, even if some |
91 | # destructor overwrote $@ as the eval was unwinding. |
92 | if ( $failed ) { |
93 | # if we got an error, invoke the catch block. |
94 | if ( $catch ) { |
95 | # This works like given($error), but is backwards compatible and |
96 | # sets $_ in the dynamic scope for the body of C<$catch> |
97 | for ($error) { |
98 | return $catch->($error); |
99 | } |
100 | |
101 | # in case when() was used without an explicit return, the C<for> |
102 | # loop will be aborted and there's no useful return value |
103 | } |
104 | |
105 | return; |
106 | } else { |
107 | # no failure, $@ is back to what it was, everything is fine |
108 | return $wantarray ? @ret : $ret[0]; |
109 | } |
3176feef |
110 | } |
111 | |
7195fc08 |
112 | sub catch (&;@) { |
8d2ee831 |
113 | my ( $block, @rest ) = @_; |
7195fc08 |
114 | |
d2ae14ad |
115 | croak 'Useless bare catch()' unless wantarray; |
9d0e0466 |
116 | |
8d2ee831 |
117 | return ( |
118 | bless(\$block, 'Try::Tiny::Catch'), |
119 | @rest, |
120 | ); |
3176feef |
121 | } |
122 | |
7195fc08 |
123 | sub finally (&;@) { |
8d2ee831 |
124 | my ( $block, @rest ) = @_; |
7195fc08 |
125 | |
d2ae14ad |
126 | croak 'Useless bare finally()' unless wantarray; |
9d0e0466 |
127 | |
8d2ee831 |
128 | return ( |
129 | bless(\$block, 'Try::Tiny::Finally'), |
130 | @rest, |
131 | ); |
7195fc08 |
132 | } |
3176feef |
133 | |
b611f396 |
134 | { |
3ef3a4f0 |
135 | package # hide from PAUSE |
136 | Try::Tiny::ScopeGuard; |
b611f396 |
137 | |
5f5e92c0 |
138 | use constant UNSTABLE_DOLLARAT => ($] < '5.013002') ? 1 : 0; |
139 | |
b611f396 |
140 | sub _new { |
141 | shift; |
142 | bless [ @_ ]; |
143 | } |
144 | |
145 | sub DESTROY { |
5f5e92c0 |
146 | my ($code, @args) = @{ $_[0] }; |
147 | |
148 | local $@ if UNSTABLE_DOLLARAT; |
149 | eval { |
150 | $code->(@args); |
151 | 1; |
152 | } or do { |
153 | warn |
154 | "Execution of finally() block $code resulted in an exception, which " |
155 | . '*CAN NOT BE PROPAGATED* due to fundamental limitations of Perl. ' |
156 | . 'Your program will continue as if this event never took place. ' |
157 | . "Original exception text follows:\n\n" |
158 | . (defined $@ ? $@ : '$@ left undefined...') |
159 | . "\n" |
160 | ; |
161 | } |
b611f396 |
162 | } |
82ef0e61 |
163 | } |
164 | |
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165 | __PACKAGE__ |
166 | |
167 | __END__ |
168 | |
169 | =pod |
170 | |
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171 | =head1 SYNOPSIS |
172 | |
a2358317 |
173 | You can use Try::Tiny's C<try> and C<catch> to expect and handle exceptional |
174 | conditions, avoiding quirks in Perl and common mistakes: |
175 | |
8d2ee831 |
176 | # handle errors with a catch handler |
177 | try { |
178 | die "foo"; |
179 | } catch { |
180 | warn "caught error: $_"; # not $@ |
181 | }; |
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182 | |
b999823d |
183 | You can also use it like a standalone C<eval> to catch and ignore any error |
a2358317 |
184 | conditions. Obviously, this is an extreme measure not to be undertaken |
185 | lightly: |
186 | |
8d2ee831 |
187 | # just silence errors |
188 | try { |
189 | die "foo"; |
190 | }; |
3176feef |
191 | |
192 | =head1 DESCRIPTION |
193 | |
7195fc08 |
194 | This module provides bare bones C<try>/C<catch>/C<finally> statements that are designed to |
1f7c5af6 |
195 | minimize common mistakes with eval blocks, and NOTHING else. |
3176feef |
196 | |
197 | This is unlike L<TryCatch> which provides a nice syntax and avoids adding |
ad10a9e2 |
198 | another call stack layer, and supports calling C<return> from the C<try> block to |
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199 | return from the parent subroutine. These extra features come at a cost of a few |
200 | dependencies, namely L<Devel::Declare> and L<Scope::Upper> which are |
1f7c5af6 |
201 | occasionally problematic, and the additional catch filtering uses L<Moose> |
202 | type constraints which may not be desirable either. |
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203 | |
1f7c5af6 |
204 | The main focus of this module is to provide simple and reliable error handling |
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205 | for those having a hard time installing L<TryCatch>, but who still want to |
206 | write correct C<eval> blocks without 5 lines of boilerplate each time. |
207 | |
208 | It's designed to work as correctly as possible in light of the various |
b999823d |
209 | pathological edge cases (see L</BACKGROUND>) and to be compatible with any style |
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210 | of error values (simple strings, references, objects, overloaded objects, etc). |
211 | |
ad10a9e2 |
212 | If the C<try> block dies, it returns the value of the last statement executed in |
213 | the C<catch> block, if there is one. Otherwise, it returns C<undef> in scalar |
c065237e |
214 | context or the empty list in list context. The following examples all |
ad10a9e2 |
215 | assign C<"bar"> to C<$x>: |
a5cd5f73 |
216 | |
8d2ee831 |
217 | my $x = try { die "foo" } catch { "bar" }; |
218 | my $x = try { die "foo" } || { "bar" }; |
219 | my $x = (try { die "foo" }) // { "bar" }; |
a5cd5f73 |
220 | |
8d2ee831 |
221 | my $x = eval { die "foo" } || "bar"; |
a5cd5f73 |
222 | |
ad10a9e2 |
223 | You can add C<finally> blocks, yielding the following: |
7195fc08 |
224 | |
8d2ee831 |
225 | my $x; |
226 | try { die 'foo' } finally { $x = 'bar' }; |
227 | try { die 'foo' } catch { warn "Got a die: $_" } finally { $x = 'bar' }; |
7195fc08 |
228 | |
ad10a9e2 |
229 | C<finally> blocks are always executed making them suitable for cleanup code |
230 | which cannot be handled using local. You can add as many C<finally> blocks to a |
231 | given C<try> block as you like. |
7195fc08 |
232 | |
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233 | =head1 EXPORTS |
234 | |
1f7c5af6 |
235 | All functions are exported by default using L<Exporter>. |
3176feef |
236 | |
7195fc08 |
237 | If you need to rename the C<try>, C<catch> or C<finally> keyword consider using |
6157bcb8 |
238 | L<Sub::Import> to get L<Sub::Exporter>'s flexibility. |
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239 | |
240 | =over 4 |
241 | |
7195fc08 |
242 | =item try (&;@) |
3176feef |
243 | |
ad10a9e2 |
244 | Takes one mandatory C<try> subroutine, an optional C<catch> subroutine and C<finally> |
7195fc08 |
245 | subroutine. |
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246 | |
247 | The mandatory subroutine is evaluated in the context of an C<eval> block. |
248 | |
1f7c5af6 |
249 | If no error occurred the value from the first block is returned, preserving |
250 | list/scalar context. |
3176feef |
251 | |
252 | If there was an error and the second subroutine was given it will be invoked |
253 | with the error in C<$_> (localized) and as that block's first and only |
254 | argument. |
255 | |
2dc64249 |
256 | C<$@> does B<not> contain the error. Inside the C<catch> block it has the same |
257 | value it had before the C<try> block was executed. |
258 | |
1f7c5af6 |
259 | Note that the error may be false, but if that happens the C<catch> block will |
1d64c1ad |
260 | still be invoked. |
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261 | |
ad10a9e2 |
262 | Once all execution is finished then the C<finally> block, if given, will execute. |
7195fc08 |
263 | |
ae5ed1be |
264 | =item catch (&;@) |
1f7c5af6 |
265 | |
266 | Intended to be used in the second argument position of C<try>. |
3176feef |
267 | |
7195fc08 |
268 | Returns a reference to the subroutine it was given but blessed as |
269 | C<Try::Tiny::Catch> which allows try to decode correctly what to do |
270 | with this code reference. |
3176feef |
271 | |
8d2ee831 |
272 | catch { ... } |
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273 | |
ad10a9e2 |
274 | Inside the C<catch> block the caught error is stored in C<$_>, while previous |
2dc64249 |
275 | value of C<$@> is still available for use. This value may or may not be |
276 | meaningful depending on what happened before the C<try>, but it might be a good |
277 | idea to preserve it in an error stack. |
ac4f5f9f |
278 | |
0a0641f9 |
279 | For code that captures C<$@> when throwing new errors (i.e. |
280 | L<Class::Throwable>), you'll need to do: |
281 | |
8d2ee831 |
282 | local $@ = $_; |
0a0641f9 |
283 | |
ae5ed1be |
284 | =item finally (&;@) |
7195fc08 |
285 | |
286 | try { ... } |
287 | catch { ... } |
288 | finally { ... }; |
289 | |
290 | Or |
291 | |
292 | try { ... } |
293 | finally { ... }; |
294 | |
295 | Or even |
296 | |
297 | try { ... } |
298 | finally { ... } |
299 | catch { ... }; |
300 | |
ad10a9e2 |
301 | Intended to be the second or third element of C<try>. C<finally> blocks are always |
7195fc08 |
302 | executed in the event of a successful C<try> or if C<catch> is run. This allows |
303 | you to locate cleanup code which cannot be done via C<local()> e.g. closing a file |
304 | handle. |
305 | |
ad10a9e2 |
306 | When invoked, the C<finally> block is passed the error that was caught. If no |
307 | error was caught, it is passed nothing. (Note that the C<finally> block does not |
308 | localize C<$_> with the error, since unlike in a C<catch> block, there is no way |
658a90e5 |
309 | to know if C<$_ == undef> implies that there were no errors.) In other words, |
310 | the following code does just what you would expect: |
d6e0f0df |
311 | |
312 | try { |
313 | die_sometimes(); |
314 | } catch { |
315 | # ...code run in case of error |
316 | } finally { |
317 | if (@_) { |
318 | print "The try block died with: @_\n"; |
319 | } else { |
320 | print "The try block ran without error.\n"; |
321 | } |
322 | }; |
323 | |
ad10a9e2 |
324 | B<You must always do your own error handling in the C<finally> block>. C<Try::Tiny> will |
7195fc08 |
325 | not do anything about handling possible errors coming from code located in these |
326 | blocks. |
327 | |
5f5e92c0 |
328 | Furthermore B<exceptions in C<finally> blocks are not trappable and are unable |
329 | to influence the execution of your program>. This is due to limitation of |
330 | C<DESTROY>-based scope guards, which C<finally> is implemented on top of. This |
331 | may change in a future version of Try::Tiny. |
332 | |
7195fc08 |
333 | In the same way C<catch()> blesses the code reference this subroutine does the same |
334 | except it bless them as C<Try::Tiny::Finally>. |
335 | |
3176feef |
336 | =back |
337 | |
338 | =head1 BACKGROUND |
339 | |
340 | There are a number of issues with C<eval>. |
341 | |
342 | =head2 Clobbering $@ |
343 | |
ad10a9e2 |
344 | When you run an C<eval> block and it succeeds, C<$@> will be cleared, potentially |
a717a876 |
345 | clobbering an error that is currently being caught. |
3176feef |
346 | |
1f7c5af6 |
347 | This causes action at a distance, clearing previous errors your caller may have |
348 | not yet handled. |
349 | |
350 | C<$@> must be properly localized before invoking C<eval> in order to avoid this |
351 | issue. |
3176feef |
352 | |
8e5b4441 |
353 | More specifically, C<$@> is clobbered at the beginning of the C<eval>, which |
511c05ca |
354 | also makes it impossible to capture the previous error before you die (for |
355 | instance when making exception objects with error stacks). |
356 | |
2b0d579d |
357 | For this reason C<try> will actually set C<$@> to its previous value (the one |
358 | available before entering the C<try> block) in the beginning of the C<eval> |
359 | block. |
511c05ca |
360 | |
3176feef |
361 | =head2 Localizing $@ silently masks errors |
362 | |
ad10a9e2 |
363 | Inside an C<eval> block, C<die> behaves sort of like: |
3176feef |
364 | |
8d2ee831 |
365 | sub die { |
366 | $@ = $_[0]; |
367 | return_undef_from_eval(); |
368 | } |
3176feef |
369 | |
370 | This means that if you were polite and localized C<$@> you can't die in that |
1f7c5af6 |
371 | scope, or your error will be discarded (printing "Something's wrong" instead). |
3176feef |
372 | |
373 | The workaround is very ugly: |
374 | |
8d2ee831 |
375 | my $error = do { |
376 | local $@; |
377 | eval { ... }; |
378 | $@; |
379 | }; |
3176feef |
380 | |
8d2ee831 |
381 | ... |
382 | die $error; |
3176feef |
383 | |
384 | =head2 $@ might not be a true value |
385 | |
386 | This code is wrong: |
387 | |
8d2ee831 |
388 | if ( $@ ) { |
389 | ... |
390 | } |
3176feef |
391 | |
1f7c5af6 |
392 | because due to the previous caveats it may have been unset. |
393 | |
1d64c1ad |
394 | C<$@> could also be an overloaded error object that evaluates to false, but |
395 | that's asking for trouble anyway. |
3176feef |
396 | |
397 | The classic failure mode is: |
398 | |
8d2ee831 |
399 | sub Object::DESTROY { |
400 | eval { ... } |
401 | } |
3176feef |
402 | |
8d2ee831 |
403 | eval { |
404 | my $obj = Object->new; |
3176feef |
405 | |
8d2ee831 |
406 | die "foo"; |
407 | }; |
3176feef |
408 | |
8d2ee831 |
409 | if ( $@ ) { |
3176feef |
410 | |
8d2ee831 |
411 | } |
3176feef |
412 | |
1f7c5af6 |
413 | In this case since C<Object::DESTROY> is not localizing C<$@> but still uses |
1d64c1ad |
414 | C<eval>, it will set C<$@> to C<"">. |
3176feef |
415 | |
1f7c5af6 |
416 | The destructor is called when the stack is unwound, after C<die> sets C<$@> to |
3176feef |
417 | C<"foo at Foo.pm line 42\n">, so by the time C<if ( $@ )> is evaluated it has |
1f7c5af6 |
418 | been cleared by C<eval> in the destructor. |
3176feef |
419 | |
1f7c5af6 |
420 | The workaround for this is even uglier than the previous ones. Even though we |
421 | can't save the value of C<$@> from code that doesn't localize, we can at least |
ad10a9e2 |
422 | be sure the C<eval> was aborted due to an error: |
3176feef |
423 | |
8d2ee831 |
424 | my $failed = not eval { |
425 | ... |
3176feef |
426 | |
8d2ee831 |
427 | return 1; |
428 | }; |
3176feef |
429 | |
1f7c5af6 |
430 | This is because an C<eval> that caught a C<die> will always return a false |
431 | value. |
3176feef |
432 | |
f9b91e2c |
433 | =head1 SHINY SYNTAX |
3176feef |
434 | |
1f7c5af6 |
435 | Using Perl 5.10 you can use L<perlsyn/"Switch statements">. |
3176feef |
436 | |
1f7c5af6 |
437 | The C<catch> block is invoked in a topicalizer context (like a C<given> block), |
438 | but note that you can't return a useful value from C<catch> using the C<when> |
27293e40 |
439 | blocks without an explicit C<return>. |
3176feef |
440 | |
441 | This is somewhat similar to Perl 6's C<CATCH> blocks. You can use it to |
442 | concisely match errors: |
443 | |
8d2ee831 |
444 | try { |
445 | require Foo; |
446 | } catch { |
447 | when (/^Can't locate .*?\.pm in \@INC/) { } # ignore |
448 | default { die $_ } |
449 | }; |
3176feef |
450 | |
451 | =head1 CAVEATS |
452 | |
453 | =over 4 |
454 | |
455 | =item * |
456 | |
013dca8f |
457 | C<@_> is not available within the C<try> block, so you need to copy your |
458 | arglist. In case you want to work with argument values directly via C<@_> |
459 | aliasing (i.e. allow C<$_[1] = "foo">), you need to pass C<@_> by reference: |
318cb1eb |
460 | |
8d2ee831 |
461 | sub foo { |
462 | my ( $self, @args ) = @_; |
463 | try { $self->bar(@args) } |
464 | } |
013dca8f |
465 | |
466 | or |
467 | |
8d2ee831 |
468 | sub bar_in_place { |
469 | my $self = shift; |
470 | my $args = \@_; |
471 | try { $_ = $self->bar($_) for @$args } |
472 | } |
318cb1eb |
473 | |
474 | =item * |
475 | |
476 | C<return> returns from the C<try> block, not from the parent sub (note that |
477 | this is also how C<eval> works, but not how L<TryCatch> works): |
478 | |
6651956b |
479 | sub parent_sub { |
8d2ee831 |
480 | try { |
481 | die; |
482 | } |
483 | catch { |
484 | return; |
485 | }; |
6651956b |
486 | |
8d2ee831 |
487 | say "this text WILL be displayed, even though an exception is thrown"; |
6651956b |
488 | } |
489 | |
490 | Instead, you should capture the return value: |
491 | |
492 | sub parent_sub { |
8d2ee831 |
493 | my $success = try { |
494 | die; |
495 | 1; |
86b8a58a |
496 | }; |
8d2ee831 |
497 | return unless $success; |
6651956b |
498 | |
8d2ee831 |
499 | say "This text WILL NEVER appear!"; |
6651956b |
500 | } |
318cb1eb |
501 | |
ad10a9e2 |
502 | Note that if you have a C<catch> block, it must return C<undef> for this to work, |
503 | since if a C<catch> block exists, its return value is returned in place of C<undef> |
6651956b |
504 | when an exception is thrown. |
318cb1eb |
505 | |
506 | =item * |
507 | |
1f7c5af6 |
508 | C<try> introduces another caller stack frame. L<Sub::Uplevel> is not used. L<Carp> |
c12e626f |
509 | will not report this when using full stack traces, though, because |
510 | C<%Carp::Internal> is used. This lack of magic is considered a feature. |
3176feef |
511 | |
512 | =item * |
513 | |
57c50f41 |
514 | The value of C<$_> in the C<catch> block is not guaranteed to be the value of |
515 | the exception thrown (C<$@>) in the C<try> block. There is no safe way to |
516 | ensure this, since C<eval> may be used unhygenically in destructors. The only |
517 | guarantee is that the C<catch> will be called if an exception is thrown. |
3176feef |
518 | |
a5cd5f73 |
519 | =item * |
520 | |
521 | The return value of the C<catch> block is not ignored, so if testing the result |
522 | of the expression for truth on success, be sure to return a false value from |
523 | the C<catch> block: |
524 | |
8d2ee831 |
525 | my $obj = try { |
526 | MightFail->new; |
527 | } catch { |
528 | ... |
a5cd5f73 |
529 | |
8d2ee831 |
530 | return; # avoid returning a true value; |
531 | }; |
a5cd5f73 |
532 | |
8d2ee831 |
533 | return unless $obj; |
a5cd5f73 |
534 | |
eaca95b7 |
535 | =item * |
536 | |
537 | C<$SIG{__DIE__}> is still in effect. |
538 | |
539 | Though it can be argued that C<$SIG{__DIE__}> should be disabled inside of |
540 | C<eval> blocks, since it isn't people have grown to rely on it. Therefore in |
541 | the interests of compatibility, C<try> does not disable C<$SIG{__DIE__}> for |
542 | the scope of the error throwing code. |
543 | |
cbfb5327 |
544 | =item * |
545 | |
546 | Lexical C<$_> may override the one set by C<catch>. |
547 | |
548 | For example Perl 5.10's C<given> form uses a lexical C<$_>, creating some |
549 | confusing behavior: |
550 | |
8d2ee831 |
551 | given ($foo) { |
552 | when (...) { |
553 | try { |
554 | ... |
555 | } catch { |
556 | warn $_; # will print $foo, not the error |
557 | warn $_[0]; # instead, get the error like this |
558 | } |
559 | } |
560 | } |
cbfb5327 |
561 | |
aaf0d61f |
562 | Note that this behavior was changed once again in L<Perl5 version 18 |
563 | |https://metacpan.org/module/perldelta#given-now-aliases-the-global-_>. |
564 | However, since the entirety of lexical C<$_> is now L<considired experimental |
565 | |https://metacpan.org/module/perldelta#Lexical-_-is-now-experimental>, it |
566 | is unclear whether the new version 18 behavior is final. |
567 | |
3176feef |
568 | =back |
569 | |
570 | =head1 SEE ALSO |
571 | |
572 | =over 4 |
573 | |
574 | =item L<TryCatch> |
575 | |
576 | Much more feature complete, more convenient semantics, but at the cost of |
577 | implementation complexity. |
578 | |
9bc603cb |
579 | =item L<autodie> |
580 | |
581 | Automatic error throwing for builtin functions and more. Also designed to |
582 | work well with C<given>/C<when>. |
583 | |
f8227e43 |
584 | =item L<Throwable> |
585 | |
586 | A lightweight role for rolling your own exception classes. |
587 | |
3176feef |
588 | =item L<Error> |
589 | |
590 | Exception object implementation with a C<try> statement. Does not localize |
591 | C<$@>. |
592 | |
593 | =item L<Exception::Class::TryCatch> |
594 | |
595 | Provides a C<catch> statement, but properly calling C<eval> is your |
596 | responsibility. |
597 | |
598 | The C<try> keyword pushes C<$@> onto an error stack, avoiding some of the |
1d64c1ad |
599 | issues with C<$@>, but you still need to localize to prevent clobbering. |
3176feef |
600 | |
601 | =back |
602 | |
faecd5a0 |
603 | =head1 LIGHTNING TALK |
604 | |
605 | I gave a lightning talk about this module, you can see the slides (Firefox |
606 | only): |
607 | |
9b3383e4 |
608 | L<http://web.archive.org/web/20100628040134/http://nothingmuch.woobling.org/talks/takahashi.xul> |
faecd5a0 |
609 | |
610 | Or read the source: |
611 | |
2245f1ae |
612 | L<http://web.archive.org/web/20100305133605/http://nothingmuch.woobling.org/talks/yapc_asia_2009/try_tiny.yml> |
faecd5a0 |
613 | |
3176feef |
614 | =head1 VERSION CONTROL |
615 | |
e5c5bdf1 |
616 | L<http://github.com/doy/try-tiny/> |
3176feef |
617 | |
3176feef |
618 | =cut |
619 | |