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Comparing JSON-XS/XS.pm (file contents):
Revision 1.94 by root, Tue Mar 25 07:46:15 2008 UTC vs.
Revision 1.99 by root, Thu Mar 27 06:37:35 2008 UTC

103 103
104package JSON::XS; 104package JSON::XS;
105 105
106use strict; 106use strict;
107 107
108our $VERSION = '2.1'; 108our $VERSION = '2.2';
109our @ISA = qw(Exporter); 109our @ISA = qw(Exporter);
110 110
111our @EXPORT = qw(encode_json decode_json to_json from_json); 111our @EXPORT = qw(encode_json decode_json to_json from_json);
112 112
113sub to_json($) { 113sub to_json($) {
462Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, 462Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,
463resulting in an invalid JSON text: 463resulting in an invalid JSON text:
464 464
465 JSON::XS->new->allow_nonref->encode ("Hello, World!") 465 JSON::XS->new->allow_nonref->encode ("Hello, World!")
466 => "Hello, World!" 466 => "Hello, World!"
467
468=item $json = $json->allow_unknown ([$enable])
469
470=item $enabled = $json->get_allow_unknown
471
472If C<$enable> is true (or missing), then C<encode> will I<not> throw an
473exception when it encounters values it cannot represent in JSON (for
474example, filehandles) but instead will encode a JSON C<null> value. Note
475that blessed objects are not included here and are handled separately by
476c<allow_nonref>.
477
478If C<$enable> is false (the default), then C<encode> will throw an
479exception when it encounters anything it cannot encode as JSON.
480
481This option does not affect C<decode> in any way, and it is recommended to
482leave it off unless you know your communications partner.
467 483
468=item $json = $json->allow_blessed ([$enable]) 484=item $json = $json->allow_blessed ([$enable])
469 485
470=item $enabled = $json->get_allow_blessed 486=item $enabled = $json->get_allow_blessed
471 487
683=back 699=back
684 700
685 701
686=head1 INCREMENTAL PARSING 702=head1 INCREMENTAL PARSING
687 703
688[This section is still EXPERIMENTAL] 704[This section and the API it details is still EXPERIMENTAL]
689 705
690In some cases, there is the need for incremental parsing of JSON 706In some cases, there is the need for incremental parsing of JSON
691texts. While this module always has to keep both JSON text and resulting 707texts. While this module always has to keep both JSON text and resulting
692Perl data structure in memory at one time, it does allow you to parse a 708Perl data structure in memory at one time, it does allow you to parse a
693JSON stream incrementally. It does so by accumulating text until it has 709JSON stream incrementally. It does so by accumulating text until it has
714return without doing anything further. This can be used to add more text 730return without doing anything further. This can be used to add more text
715in as many chunks as you want. 731in as many chunks as you want.
716 732
717If the method is called in scalar context, then it will try to extract 733If the method is called in scalar context, then it will try to extract
718exactly I<one> JSON object. If that is successful, it will return this 734exactly I<one> JSON object. If that is successful, it will return this
719object, otherwise it will return C<undef>. This is the most common way of 735object, otherwise it will return C<undef>. If there is a parse error,
736this method will croak just as C<decode> would do (one can then use
737C<incr_skip> to skip the errornous part). This is the most common way of
720using the method. 738using the method.
721 739
722And finally, in list context, it will try to extract as many objects 740And finally, in list context, it will try to extract as many objects
723from the stream as it can find and return them, or the empty list 741from the stream as it can find and return them, or the empty list
724otherwise. For this to work, there must be no separators between the JSON 742otherwise. For this to work, there must be no separators between the JSON
725objects or arrays, instead they must be concatenated back-to-back. 743objects or arrays, instead they must be concatenated back-to-back. If
744an error occurs, an exception will be raised as in the scalar context
745case. Note that in this case, any previously-parsed JSON texts will be
746lost.
726 747
727=item $lvalue_string = $json->incr_text 748=item $lvalue_string = $json->incr_text
728 749
729This method returns the currently stored JSON fragment as an lvalue, that 750This method returns the currently stored JSON fragment as an lvalue, that
730is, you can manipulate it. This I<only> works when a preceding call to 751is, you can manipulate it. This I<only> works when a preceding call to
735method before having parsed anything. 756method before having parsed anything.
736 757
737This function is useful in two cases: a) finding the trailing text after a 758This function is useful in two cases: a) finding the trailing text after a
738JSON object or b) parsing multiple JSON objects separated by non-JSON text 759JSON object or b) parsing multiple JSON objects separated by non-JSON text
739(such as commas). 760(such as commas).
761
762=item $json->incr_skip
763
764This will reset the state of the incremental parser and will remove the
765parsed text from the input buffer. This is useful after C<incr_parse>
766died, in which case the input buffer and incremental parser state is left
767unchanged, to skip the text parsed so far and to reset the parse state.
740 768
741=back 769=back
742 770
743=head2 LIMITATIONS 771=head2 LIMITATIONS
744 772
1133as UTF-8, ISO-8859-1, ASCII, KOI8-R or most about any character set and 1161as UTF-8, ISO-8859-1, ASCII, KOI8-R or most about any character set and
11348-bit-encoding, and still get the same data structure back. This is useful 11628-bit-encoding, and still get the same data structure back. This is useful
1135when your channel for JSON transfer is not 8-bit clean or the encoding 1163when your channel for JSON transfer is not 8-bit clean or the encoding
1136might be mangled in between (e.g. in mail), and works because ASCII is a 1164might be mangled in between (e.g. in mail), and works because ASCII is a
1137proper subset of most 8-bit and multibyte encodings in use in the world. 1165proper subset of most 8-bit and multibyte encodings in use in the world.
1138
1139=back
1140
1141
1142=head1 COMPARISON
1143
1144As already mentioned, this module was created because none of the existing
1145JSON modules could be made to work correctly. First I will describe the
1146problems (or pleasures) I encountered with various existing JSON modules,
1147followed by some benchmark values. JSON::XS was designed not to suffer
1148from any of these problems or limitations.
1149
1150=over 4
1151
1152=item JSON 2.xx
1153
1154A marvellous piece of engineering, this module either uses JSON::XS
1155directly when available (so will be 100% compatible with it, including
1156speed), or it uses JSON::PP, which is basically JSON::XS translated to
1157Pure Perl, which should be 100% compatible with JSON::XS, just a bit
1158slower.
1159
1160You cannot really lose by using this module, especially as it tries very
1161hard to work even with ancient Perl versions, while JSON::XS does not.
1162
1163=item JSON 1.07
1164
1165Slow (but very portable, as it is written in pure Perl).
1166
1167Undocumented/buggy Unicode handling (how JSON handles Unicode values is
1168undocumented. One can get far by feeding it Unicode strings and doing
1169en-/decoding oneself, but Unicode escapes are not working properly).
1170
1171No round-tripping (strings get clobbered if they look like numbers, e.g.
1172the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will
1173decode into the number 2.
1174
1175=item JSON::PC 0.01
1176
1177Very fast.
1178
1179Undocumented/buggy Unicode handling.
1180
1181No round-tripping.
1182
1183Has problems handling many Perl values (e.g. regex results and other magic
1184values will make it croak).
1185
1186Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}>
1187which is not a valid JSON text.
1188
1189Unmaintained (maintainer unresponsive for many months, bugs are not
1190getting fixed).
1191
1192=item JSON::Syck 0.21
1193
1194Very buggy (often crashes).
1195
1196Very inflexible (no human-readable format supported, format pretty much
1197undocumented. I need at least a format for easy reading by humans and a
1198single-line compact format for use in a protocol, and preferably a way to
1199generate ASCII-only JSON texts).
1200
1201Completely broken (and confusingly documented) Unicode handling (Unicode
1202escapes are not working properly, you need to set ImplicitUnicode to
1203I<different> values on en- and decoding to get symmetric behaviour).
1204
1205No round-tripping (simple cases work, but this depends on whether the scalar
1206value was used in a numeric context or not).
1207
1208Dumping hashes may skip hash values depending on iterator state.
1209
1210Unmaintained (maintainer unresponsive for many months, bugs are not
1211getting fixed).
1212
1213Does not check input for validity (i.e. will accept non-JSON input and
1214return "something" instead of raising an exception. This is a security
1215issue: imagine two banks transferring money between each other using
1216JSON. One bank might parse a given non-JSON request and deduct money,
1217while the other might reject the transaction with a syntax error. While a
1218good protocol will at least recover, that is extra unnecessary work and
1219the transaction will still not succeed).
1220
1221=item JSON::DWIW 0.04
1222
1223Very fast. Very natural. Very nice.
1224
1225Undocumented Unicode handling (but the best of the pack. Unicode escapes
1226still don't get parsed properly).
1227
1228Very inflexible.
1229
1230No round-tripping.
1231
1232Does not generate valid JSON texts (key strings are often unquoted, empty keys
1233result in nothing being output)
1234
1235Does not check input for validity.
1236 1166
1237=back 1167=back
1238 1168
1239 1169
1240=head2 JSON and YAML 1170=head2 JSON and YAML

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