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Re: [Json] -0.0

Carsten Bormann <cabo@tzi.org> Sun, 29 September 2013 08:31 UTC

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From: Carsten Bormann <cabo@tzi.org>
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Date: Sun, 29 Sep 2013 10:31:40 +0200
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To: R S <sayrer@gmail.com>
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Subject: Re: [Json] -0.0
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On Sep 28, 2013, at 00:15, R S <sayrer@gmail.com> wrote:

>> Yes. The text in the current draft refers to both -0 and -0.0 as though they are interoperable.
> 
> Rather, it refers to them both as though they have the same interoperability considerations.

Rightly so.

While the probability of being hit is lower (more JSON implementations do seem to implement -0.0 as distinct from 0.0), it would still be foolish to rely on interoperability of any form of negative zero.

(Two minutes of googling:
https://android.googlesource.com/platform/libcore/+/014aa1a70743ae7e6ec0de1555f5b43d43844cf4/json/src/main/java/org/json/JSONObject.java
I haven't investigated further.)

Note also the result on -0e0.

More importantly, the JSON specification so far has been mute on negative zeros (random quote from someone trying to interpret the specification: "The JSON specification allows that number, but does not define what it means"*).

(Going forward, it would probably be a good thing to recommend that JSON decoders represent all of -0, -0e0 etc. in a number representation that keeps negative zeros distinct; that is for most of them, treat -0 as a floating point value.  Examples of implementations that do so: Erlang's, JSONKit, demjson.)

Grüße, Carsten

*) http://deron.meranda.us/python/comparing_json_modules/numbers

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