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85 | |
85 | |
86 | package JSON::XS; |
86 | package JSON::XS; |
87 | |
87 | |
88 | use strict; |
88 | use strict; |
89 | |
89 | |
90 | BEGIN { |
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91 | our $VERSION = '1.24'; |
90 | our $VERSION = '1.4'; |
92 | our @ISA = qw(Exporter); |
91 | our @ISA = qw(Exporter); |
93 | |
92 | |
94 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
93 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
95 | require Exporter; |
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96 | |
94 | |
97 | require XSLoader; |
95 | use Exporter; |
98 | XSLoader::load JSON::XS::, $VERSION; |
96 | use XSLoader; |
99 | } |
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100 | |
97 | |
101 | =head1 FUNCTIONAL INTERFACE |
98 | =head1 FUNCTIONAL INTERFACE |
102 | |
99 | |
103 | The following convinience methods are provided by this module. They are |
100 | The following convinience methods are provided by this module. They are |
104 | exported by default: |
101 | exported by default: |
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126 | This function call is functionally identical to: |
123 | This function call is functionally identical to: |
127 | |
124 | |
128 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
125 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
129 | |
126 | |
130 | except being faster. |
127 | except being faster. |
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128 | |
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129 | =item $is_boolean = JSON::XS::is_bool $scalar |
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130 | |
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131 | Returns true if the passed scalar represents either JSON::XS::true or |
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132 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
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133 | and are used to represent JSON C<true> and C<false> values in Perl. |
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134 | |
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135 | See MAPPING, below, for more information on how JSON values are mapped to |
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136 | Perl. |
131 | |
137 | |
132 | =back |
138 | =back |
133 | |
139 | |
134 | |
140 | |
135 | =head1 OBJECT-ORIENTED INTERFACE |
141 | =head1 OBJECT-ORIENTED INTERFACE |
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309 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
315 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
310 | resulting in an invalid JSON text: |
316 | resulting in an invalid JSON text: |
311 | |
317 | |
312 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
318 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
313 | => "Hello, World!" |
319 | => "Hello, World!" |
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320 | |
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321 | =item $json = $json->allow_blessed ([$enable]) |
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322 | |
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323 | If C<$enable> is true (or missing), then the C<encode> method will not |
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324 | barf when it encounters a blessed reference. Instead, the value of the |
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325 | B<convert_blessed> option will decide wether C<null> (C<convert_blessed> |
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326 | disabled or no C<to_json> method found) or a representation of the |
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327 | object (C<convert_blessed> enabled and C<to_json> method found) is being |
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328 | encoded. Has no effect on C<decode>. |
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329 | |
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330 | If C<$enable> is false (the default), then C<encode> will throw an |
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331 | exception when it encounters a blessed object. |
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332 | |
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333 | =item $json = $json->convert_blessed ([$enable]) |
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334 | |
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335 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
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336 | blessed object, will check for the availability of the C<TO_JSON> method |
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337 | on the object's class. If found, it will be called in scalar context |
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338 | and the resulting scalar will be encoded instead of the object. If no |
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339 | C<TO_JSON> method is found, the value of C<allow_blessed> will decide what |
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340 | to do. |
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341 | |
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342 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
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343 | returns other blessed objects, those will be handled in the same |
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344 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
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345 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
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346 | methods called by the Perl core (== not by the user of the object) are |
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347 | usually in upper case letters and to avoid collisions with the C<to_json> |
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348 | function. |
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349 | |
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350 | This setting does not yet influence C<decode> in any way, but in the |
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351 | future, global hooks might get installed that influence C<decode> and are |
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352 | enabled by this setting. |
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353 | |
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354 | If C<$enable> is false, then the C<allow_blessed> setting will decide what |
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355 | to do when a blessed object is found. |
314 | |
356 | |
315 | =item $json = $json->shrink ([$enable]) |
357 | =item $json = $json->shrink ([$enable]) |
316 | |
358 | |
317 | Perl usually over-allocates memory a bit when allocating space for |
359 | Perl usually over-allocates memory a bit when allocating space for |
318 | strings. This flag optionally resizes strings generated by either |
360 | strings. This flag optionally resizes strings generated by either |
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351 | given character in a string. |
393 | given character in a string. |
352 | |
394 | |
353 | Setting the maximum depth to one disallows any nesting, so that ensures |
395 | Setting the maximum depth to one disallows any nesting, so that ensures |
354 | that the object is only a single hash/object or array. |
396 | that the object is only a single hash/object or array. |
355 | |
397 | |
356 | The argument to C<max_depth> will be rounded up to the next nearest power |
398 | The argument to C<max_depth> will be rounded up to the next highest power |
357 | of two. |
399 | of two. If no argument is given, the highest possible setting will be |
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400 | used, which is rarely useful. |
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401 | |
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402 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
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403 | |
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404 | =item $json = $json->max_size ([$maximum_string_size]) |
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405 | |
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406 | Set the maximum length a JSON text may have (in bytes) where decoding is |
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407 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
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408 | is called on a string longer then this number of characters it will not |
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409 | attempt to decode the string but throw an exception. This setting has no |
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410 | effect on C<encode> (yet). |
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411 | |
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412 | The argument to C<max_size> will be rounded up to the next B<highest> |
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413 | power of two (so may be more than requested). If no argument is given, the |
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414 | limit check will be deactivated (same as when C<0> is specified). |
358 | |
415 | |
359 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
416 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
360 | |
417 | |
361 | =item $json_text = $json->encode ($perl_scalar) |
418 | =item $json_text = $json->encode ($perl_scalar) |
362 | |
419 | |
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432 | conversion details, but an integer may take slightly less memory and might |
489 | conversion details, but an integer may take slightly less memory and might |
433 | represent more values exactly than (floating point) numbers. |
490 | represent more values exactly than (floating point) numbers. |
434 | |
491 | |
435 | =item true, false |
492 | =item true, false |
436 | |
493 | |
437 | These JSON atoms become C<0>, C<1>, respectively. Information is lost in |
494 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
438 | this process. Future versions might represent those values differently, |
495 | respectively. They are overloaded to act almost exactly like the numbers |
439 | but they will be guarenteed to act like these integers would normally in |
496 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
440 | Perl. |
497 | the C<JSON::XS::is_bool> function. |
441 | |
498 | |
442 | =item null |
499 | =item null |
443 | |
500 | |
444 | A JSON null atom becomes C<undef> in Perl. |
501 | A JSON null atom becomes C<undef> in Perl. |
445 | |
502 | |
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477 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
534 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
478 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
535 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
479 | |
536 | |
480 | to_json [\0,JSON::XS::true] # yields [false,true] |
537 | to_json [\0,JSON::XS::true] # yields [false,true] |
481 | |
538 | |
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539 | =item JSON::XS::true, JSON::XS::false |
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540 | |
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541 | These special values become JSON true and JSON false values, |
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542 | respectively. You cna alos use C<\1> and C<\0> directly if you want. |
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543 | |
482 | =item blessed objects |
544 | =item blessed objects |
483 | |
545 | |
484 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
546 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
485 | underlying representation (hash- or arrayref), but this behaviour might |
547 | underlying representation (hash- or arrayref), but this behaviour might |
486 | change in future versions. |
548 | change in future versions. |
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649 | It shows the number of encodes/decodes per second (JSON::XS uses |
711 | It shows the number of encodes/decodes per second (JSON::XS uses |
650 | the functional interface, while JSON::XS/2 uses the OO interface |
712 | the functional interface, while JSON::XS/2 uses the OO interface |
651 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
713 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
652 | shrink). Higher is better: |
714 | shrink). Higher is better: |
653 | |
715 | |
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716 | Storable | 15779.925 | 14169.946 | |
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717 | -----------+------------+------------+ |
654 | module | encode | decode | |
718 | module | encode | decode | |
655 | -----------|------------|------------| |
719 | -----------|------------|------------| |
656 | JSON | 7645.468 | 4208.613 | |
720 | JSON | 4990.842 | 4088.813 | |
657 | JSON::DWIW | 40721.398 | 77101.176 | |
721 | JSON::DWIW | 51653.990 | 71575.154 | |
658 | JSON::PC | 65948.176 | 78251.940 | |
722 | JSON::PC | 65948.176 | 74631.744 | |
659 | JSON::Syck | 22844.793 | 26479.192 | |
723 | JSON::PP | 8931.652 | 3817.168 | |
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724 | JSON::Syck | 24877.248 | 27776.848 | |
660 | JSON::XS | 388361.481 | 199728.762 | |
725 | JSON::XS | 388361.481 | 227951.304 | |
661 | JSON::XS/2 | 218453.333 | 192399.266 | |
726 | JSON::XS/2 | 227951.304 | 218453.333 | |
662 | JSON::XS/3 | 338250.323 | 192399.266 | |
727 | JSON::XS/3 | 338250.323 | 218453.333 | |
663 | Storable | 15779.925 | 14169.946 | |
728 | Storable | 16500.016 | 135300.129 | |
664 | -----------+------------+------------+ |
729 | -----------+------------+------------+ |
665 | |
730 | |
666 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
731 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
667 | about three times faster on decoding, and over fourty times faster |
732 | about three times faster on decoding, and over fourty times faster |
668 | than JSON, even with pretty-printing and key sorting. It also compares |
733 | than JSON, even with pretty-printing and key sorting. It also compares |
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671 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
736 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
672 | search API (http://nanoref.com/yahooapis/mgPdGg): |
737 | search API (http://nanoref.com/yahooapis/mgPdGg): |
673 | |
738 | |
674 | module | encode | decode | |
739 | module | encode | decode | |
675 | -----------|------------|------------| |
740 | -----------|------------|------------| |
676 | JSON | 254.685 | 37.665 | |
741 | JSON | 55.260 | 34.971 | |
677 | JSON::DWIW | 843.343 | 1049.731 | |
742 | JSON::DWIW | 825.228 | 1082.513 | |
678 | JSON::PC | 3602.116 | 2307.352 | |
743 | JSON::PC | 3571.444 | 2394.829 | |
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744 | JSON::PP | 210.987 | 32.574 | |
679 | JSON::Syck | 505.107 | 787.899 | |
745 | JSON::Syck | 552.551 | 787.544 | |
680 | JSON::XS | 5747.196 | 3690.220 | |
746 | JSON::XS | 5780.463 | 4854.519 | |
681 | JSON::XS/2 | 3968.121 | 3676.634 | |
747 | JSON::XS/2 | 3869.998 | 4798.975 | |
682 | JSON::XS/3 | 6105.246 | 3662.508 | |
748 | JSON::XS/3 | 5862.880 | 4798.975 | |
683 | Storable | 4417.337 | 5285.161 | |
749 | Storable | 4445.002 | 5235.027 | |
684 | -----------+------------+------------+ |
750 | -----------+------------+------------+ |
685 | |
751 | |
686 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
752 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
687 | decodes faster). |
753 | decodes faster). |
688 | |
754 | |
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705 | Second, you need to avoid resource-starving attacks. That means you should |
771 | Second, you need to avoid resource-starving attacks. That means you should |
706 | limit the size of JSON texts you accept, or make sure then when your |
772 | limit the size of JSON texts you accept, or make sure then when your |
707 | resources run out, thats just fine (e.g. by using a separate process that |
773 | resources run out, thats just fine (e.g. by using a separate process that |
708 | can crash safely). The size of a JSON text in octets or characters is |
774 | can crash safely). The size of a JSON text in octets or characters is |
709 | usually a good indication of the size of the resources required to decode |
775 | usually a good indication of the size of the resources required to decode |
710 | it into a Perl structure. |
776 | it into a Perl structure. While JSON::XS can check the size of the JSON |
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777 | text, it might be too late when you already have it in memory, so you |
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778 | might want to check the size before you accept the string. |
711 | |
779 | |
712 | Third, JSON::XS recurses using the C stack when decoding objects and |
780 | Third, JSON::XS recurses using the C stack when decoding objects and |
713 | arrays. The C stack is a limited resource: for instance, on my amd64 |
781 | arrays. The C stack is a limited resource: for instance, on my amd64 |
714 | machine with 8MB of stack size I can decode around 180k nested arrays but |
782 | machine with 8MB of stack size I can decode around 180k nested arrays but |
715 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
783 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
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738 | still relatively early in its development. If you keep reporting bugs they |
806 | still relatively early in its development. If you keep reporting bugs they |
739 | will be fixed swiftly, though. |
807 | will be fixed swiftly, though. |
740 | |
808 | |
741 | =cut |
809 | =cut |
742 | |
810 | |
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811 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
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812 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
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813 | |
743 | sub true() { \1 } |
814 | sub true() { $true } |
744 | sub false() { \0 } |
815 | sub false() { $false } |
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816 | |
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817 | sub is_bool($) { |
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818 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
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819 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
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820 | } |
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821 | |
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822 | XSLoader::load "JSON::XS", $VERSION; |
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823 | |
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824 | package JSON::XS::Boolean; |
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825 | |
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826 | use overload |
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827 | "0+" => sub { ${$_[0]} }, |
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828 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
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829 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
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830 | fallback => 1; |
745 | |
831 | |
746 | 1; |
832 | 1; |
747 | |
833 | |
748 | =head1 AUTHOR |
834 | =head1 AUTHOR |
749 | |
835 | |