Re: [boost] [gsoc 2008] JSON Archives for Boost.serialization

From: Robin Redeker (elmex_at_[hidden])
Date: 2008-03-20 20:35:15

Hello Esteve!

On Thu, Mar 20, 2008 at 10:10:07PM +0100, Esteve Fernandez wrote:
> - the JSON spec is quite simple, but given that it's a subset of YAML 
> (actually Syck parses JSON as well), should it support it in the future as 
> well?

Actually JSON is not really a subset of YAML, see also the documentation
of the Perl module of Marc Lehmann, who wrote a fully standards
compliant JSON parser in (C, bound to Perl):

   http://search.cpan.org/~mlehmann/JSON-XS-2.1/XS.pm

Look at the comparsion in the section 'YAML and JSON'.

> - what about Unicode? I know that Boost.Regex supports Unicode if compiled 
> against ICU and the JSON spec states that everything must be in Unicode 
> (correct me if I'm wrong)

Yes, the JSON spec states that JSON is Unicode text, encoded in (any)
Unicode encoding (usually UTF-8). However, there is one hard part when
writing a JSON parser, you have to take care to handle the \uXXXX
literals in strings correctly. The JSON spec (RFC 4627,
http://www.ietf.org/rfc/rfc4627.txt ) states in section 2.5:

      To escape an extended character that is not in the Basic
      Multilingual Plane, the character is represented as a
      twelve-character sequence, encoding the UTF-16 surrogate pair.
      So, for example, a string containing only the G clef character
      (U+1D11E) may be represented as "\uD834\uDD1E".

So care must be taken not to overlook this small detail.

> - TinyJSON and JSON.Spirit both use a MIT-like license (JSON.Spirit is 
> licensed under CPOL). The Boost license is compatible with them but, could it 
> pose a problem? There's JSONcpp [1] as well, which is public domain.

I wrote a JSON parser in C++, which I didn't release yet, which should
be almost 100% compliant with the JSON RFC. However, I defined my own
bytebuffer class with special UTF-8 handling, as I only have to deal
with UTF-8 in my problem domain.

But I could release the code under the boost license anytime if someone
is interested. But I guess for Boost inclusion there still has to be
done some work.

Greetings,
   Robin Redeker

-- 
Robin Redeker                         | Deliantra, the free code+content MORPG
elmex_at_[hidden] / r.redeker_at_[hidden] | http://www.deliantra.net
http://www.ta-sa.org/                 |