Re: [Json] Limitations on number size?

Tim Bray <tbray@textuality.com> Thu, 11 July 2013 22:56 UTC

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Date: Thu, 11 Jul 2013 15:56:30 -0700
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From: Tim Bray <tbray@textuality.com>
To: Francis Galiegue <fgaliegue@gmail.com>
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Subject: Re: [Json] Limitations on number size?
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On Thu, Jul 11, 2013 at 3:41 PM, Francis Galiegue <fgaliegue@gmail.com>wrote;wrote:

> I agree, but then it is up to the protocols to define that. Say you
> want to exchange prices over JSON, then it makes sense to require that
> numbers be limited to two digits after the decimal point and, why not,
> require that scientific notation not be used. (and 0.01 cannot be
> represented reliably with a 64bit IEEE 754 floating point number, too)
>

Well yeah, but most programmers want to use generic non-app-sensitive
libraries to deserialize JSON into structs or objects or database records
or whatever, and if you send a 78-digit number that will usually break.  So
as long as you have pre-agreement and a flexible enough library, you’re
probably good.  This is the main reason I thought I-JSON was worth
defining, to maximize the chance that you can use a nice simple library at
both ends and have the lowest possible chance of breakage. -T


>
> But I believe this is not the role of JSON proper to define that.
>
> > [...] If we specify no semantics then we're stuck with either the
> > maximal interpretation of the grammar (binary strings! bignums! allow
> > dup names! [since no specific handling of dup names can be considered
> > a maximal interpretation...]) or an agreed subset, de facto or de
> > jure.
> >
>
> I don't believe duplicate object names are quite the same level. This
> was rather an oversight of RFC 4627 imho.
>
> --
> Francis Galiegue, fgaliegue@gmail.com
> JSON Schema in Java: http://json-schema-validator.herokuapp.com
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