Fwd: [Yaml-core] Fwd: Hash style comments

From: Oren Ben-Kiki <oren at ben-kiki.org>
Date: Thu, Aug 9, 2012 at 3:21 AM
Subject: Re: [Yaml-core] Fwd: Hash style comments
To: Trans <transfire at gmail.com>
Cc: Yaml-core <yaml-core at lists.sourceforge.net>

>
> Pedantry alert: someone noticed that JSON does not treat U+2028 and
> U+2029 (line terminators in JS) as space characters. So these can
> occur (unescaped) in JSON string literals, but not in JS string
> literals. Therefore JSON accepts sentences not legal in JS:
>
> js> JSON.parse('{"a":"\u2028","b":2}')
> ({a:"\u2028", b:2})
> js> eval('({"a":"\u2028","b":2})')
> typein:11: SyntaxError: unterminated string literal:
> typein:11: ({"a":"(
> typein:11: ......^
>
> Does YAML treat U+2028 and U+2029 the same as JSON does, or as JS does?

YAML doesn't do any special treatment of characters above 0xFF;  it
assumes all valid Unicode code points above 0xFF are
non-break-non-white "printable" characters and allows them to be used
most anywhere.

We used to treat NEL, LS, PS as line breaks but we gave it up to
maintain JSON compatibility. We are OK as long as YAML is a superset
of JSON, which seems to be the case.

Oren.

just in case, since mentioned here ...

https://github.com/WebReflection/JSONH#javascript-and-native-json-escape-problems

to make stringified JSON safer so that

JSONH.stringify(data).replace(
    /\u2028|\u2029/g,
    function (m) {
        return "\\u202" + (m === "\u2028" ? "8" : "9");
    })

cheers

On Thu, Aug 9, 2012 at 2:18 PM, Trans <transfire at gmail.com> wrote:

> From: Oren Ben-Kiki <oren at ben-kiki.org>
> Date: Thu, Aug 9, 2012 at 3:21 AM
> Subject: Re: [Yaml-core] Fwd: Hash style comments
> To: Trans <transfire at gmail.com>
> Cc: Yaml-core <yaml-core at lists.sourceforge.net>
>
> >
> > Pedantry alert: someone noticed that JSON does not treat U+2028 and
> > U+2029 (line terminators in JS) as space characters. So these can
> > occur (unescaped) in JSON string literals, but not in JS string
> > literals. Therefore JSON accepts sentences not legal in JS:
> >
> > js> JSON.parse('{"a":"\u2028","b":2}')
> > ({a:"\u2028", b:2})
> > js> eval('({"a":"\u2028","b":2})')
> > typein:11: SyntaxError: unterminated string literal:
> > typein:11: ({"a":"(
> > typein:11: ......^
> >
> > Does YAML treat U+2028 and U+2029 the same as JSON does, or as JS does?
>
> YAML doesn't do any special treatment of characters above 0xFF;  it
> assumes all valid Unicode code points above 0xFF are
> non-break-non-white "printable" characters and allows them to be used
> most anywhere.
>
> We used to treat NEL, LS, PS as line breaks but we gave it up to
> maintain JSON compatibility. We are OK as long as YAML is a superset
> of JSON, which seems to be the case.
>
> Oren.
> _______________________________________________
> es-discuss mailing list
> es-discuss at mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
>
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