Re: [Json] Unpaired surrogates in JSON strings

[Tim Bray <[e-mail]>]

On Wed, Jun 5, 2013 at 5:58 PM, Paul Hoffman <[e-mail]> wrote:

> > Escape sequences between \uD800 and \uDFFF SHOULD be generated only as
> > valid UTF16 surrogate pairs
>

Turn it into MUST. The intent of 4627 is perfectly clear, even if the BNF
is buggy.  I don’t think this rewrite should allow things that the previous
spec didn’t. -T



> (this SHOULD is only to allow backward
> > compatibility).  When encountering an invalid surrogate pair (such as
> > "foo\uD834bar" or "\uDD1E\uD834"), parsers MAY either throw an error
> > (taking the risk of some backward incompatibility with old generators) or
> > MAY ignore the sequence.
>
> Alternate proposal:
>
> Code points between U+D800 and U+DFFF SHOULD be generated only as
> valid UTF16 surrogate pairs; this SHOULD is only to allow backward
> compatibility with applications that ignored the restriction that
> strings consist of Unicode characters. A parser that encounters
> an invalid surrogate pair (such as "foo\uD834bar" or "\uDD1E\uD834"),
> SHOULD throw an error because the string does not consist of characters;
> it might ignore the errant code points, but at the risk of allowing
> strings that other parsers would find illegal.
>
> --Paul Hoffman
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