On Jun 8, 2010, at 8:46 PM, Garrett Smith wrote:
> Today I looked for a good json regexp tester and finding nothing,
> decided to write one.
>
> The strategy that occurred to me was to first define a regex for the
> literal components (ES5 lumps literal value into the JSONValue
> alongside JSONObject and JSONArray). That way, I could reuse the
> literal components to define JSONObject and JSONArray.
>
> In the process, I noticed that the grammar defined for JSONNumber is
> different than that defiend by json2.js, which I had just looked at,
> and which has similar numeric parsing as seen in The GOod parts. That
> is, it allows DecimalLiteral, which includes this production:
>
> DecimalIntegerLiteral .
>
> In contrast, JSONNumber does not allow that.
>
> JSONNumber ::
> -opt DecimalIntegerLiteral JSONFractionopt ExponentPartopt
>
> Am I misreading the spec, or is "1." not valid JSON?
>
> Next step was to see what the browsers do.
>
> Mozilla and IE accept it, while Webkit and Opera throws an error.
>
> JSON.parse("1.")
>
> Firefox 3.6, IE8, Besen r27:
> 1
>
> Safari, Opera
> SyntaxError
>
> IF anyone has a correct JSON parser, I would appreciate it. Also, are
> there any good test suites for JSON?
I spent quite a bit of time ensuring JSC's JSON parser exactly matched the spec
grammar, and hence exhibits this behaviour so I believe the parser in JSC is
"correct" -- if you're interested the code can be found at (note that it's
under an MIT style license)
http://trac.webkit.org/browser/trunk/JavaScriptCore/runtime/LiteralParser.cpp
At the time I recall talking a bit with Hallvord Steen of Opera, and he was
working on a testsuite of some sort but I can no longer recall the url.
That said I think allowing '1.' (etc) makes sense as it's fairly standard
across multiple programming languages, and I am unaware of any specific reason
for disallowing it.
In the long term I don't see changing the grammar to allow a trailing period as
being harmful as it's a relaxation. In the short term vendors that follow the
spec may fail to parse content :-(
--Oliver
>
> Garrett
> _______________________________________________
> es-discuss mailing list
> [email protected]
> https://mail.mozilla.org/listinfo/es-discuss
_______________________________________________
es-discuss mailing list
[email protected]
https://mail.mozilla.org/listinfo/es-discuss
