JSON5 support for std.json

[Idan Arye via Digitalmars-d]

On Monday, 30 November 2015 at 01:02:38 UTC, Jonathan M Davis 
wrote:
> On Monday, 30 November 2015 at 00:30:07 UTC, Chris Wright wrote:
>> I'm considering adding JSON5 support to std.json and want to 
>> know how well this would be received.
>>
>> JSON5 is pretty much just modern JavaScript's object literal 
>> format, allowing things like comments, trailing commas, and 
>> single-quoted strings.
>>
>> I only plan to add support for parsing JSON5, not emitting it. 
>> So there should be no compatibility concerns with what 
>> std.json emits.
>>
>> Since it's technically a breaking change (people can use 
>> std.json currently to validate that a document is valid JSON), 
>> I am inclined to make JSON5 be off by default and add an 
>> option to parse JSON5 rather than JSON1. Anyone have strong 
>> feelings about this?
>
> Having a JSON 5 parser makes some sense, but I don't think that 
> it makes any sense to have one which can parse JSON 5 but not 
> emit it. Either you're dealing with JSON 5 or you're not, and 
> the historical approach of the internet to be lax in what you 
> accept and strict what you emit has proven to be a horrible 
> approach IMHO.

It's pointless to emit most of the JSON5 relaxations - I see no 
reason why the emitter should specifically add trailing commas, 
and I don't see how it can emit comments...

The only JSON5 feature that is not syntactic sugar is the special 
floating point values, and the current std.json halfway supports 
it if you use `JSONOptions.specialFloatLiterals` - 
http://dpaste.dzfl.pl/42bbe53e00f9. "NaN" is emitted the same as 
JSON5, but for infinity we emit "Infinite" while JSON5 specifies 
"Infinity".