Re: [Jcardcal] Integers in jCard

The header of each section does include a reference to the corresponding
section of the vCard specification.  Is that enough?  I agree that these
limitations are unlikely to be encountered in the majority of use-cases.

Mike

On Sun, Sep 1, 2013 at 10:19 PM, Bert Greevenbosch <
Bert.Greevenbosch@huawei.com> wrote:

> Hi all,
>
> @Michael: thanks for pointing out the issue with floats. Indeed floats may
> require conversion too.
>
> There may be some problems with the conversion though. For example, it
> seems hard to convert a floating point number 3.456*10^-127 to a form
> without exponential. It is quite interesting to note that the vCard
> specification RFC 6350 forbids usage of exponentials (scientific notation),
> but at the same time requires similar precision as binary64.
>
> This does not hold for huge integers, such as 2.84*10^127, as RFC 6350
> gives explicit boundaries for integers (9223372036854775807 to
> -9223372036854775808) and the converter can break off and output an error
> in case these boundaries are not obeyed. With integers an issue could be a
> "false integer", which is actually a non-integer number with "integer"
> value type.
>
> So I guess the jCard to vCard converter needs to make some decisions on
> which values are acceptable, and for which values it should abort the
> conversion and generate an error. It may need to round values to a certain
> precision, in which case there would be some semantic loss. I have the
> suspicion that this is more a theoretical problem than a practical problem,
> as in practice arbitrary precision or number height may not be required.
> However, something could have gone wrong (whether or not on purpose), and
> implementations should be ready for this.
>
> Before I propose some extra text on this, I would like to gather related
> opinions?
>
> Thanks and best regards,
> Bert
>
>
> ---
> From: Michael Angstadt [mailto:mike.angstadt@gmail.com]
> Sent: 2013年8月30日 20:59
> To: Bert Greevenbosch
> Cc: jcardcal@ietf.org; Barry Leiba; Philipp Kewisch
> Subject: Re: [Jcardcal] Integers in jCard
>
>
> On Thu, Aug 29, 2013 at 10:12 PM, Bert Greevenbosch <
> Bert.Greevenbosch@huawei.com> wrote:
> To me, it seems impractical to forbid using decimals and exponents for
> jCard integers. A general JSON parser (which is oblivious of jCard) would
> ignore any such requirement anyway.
>
> Agreed.  A similar statement should be added to the "float" section
> (3.4.10) about permitting exponents to be used.
>
> BEGIN
>   Note: Neither JSON nor jCard prohibits using exponents to form
>   a float number. However, since vCard does not support
>   exponents in floats, any exponents MUST be eliminated when
>   converting a "float" value type property from jCard to vCard.
> END;
>
> Perhaps these changes should be applied to the jCal draft as well, since
> jCal also defines "integer" and "float" data types.
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