Re: [Scheme-reports] digit-value Marc Feeley (01 Jul 2012 12:55 UTC)
Re: [Scheme-reports] digit-value Alex Shinn (01 Jul 2012 20:28 UTC)
Re: [Scheme-reports] digit-value Marc Feeley (02 Jul 2012 12:08 UTC)
Re: [Scheme-reports] digit-value Alaric Snell-Pym (02 Jul 2012 12:21 UTC)
Re: [Scheme-reports] digit-value John Cowan (03 Jul 2012 07:16 UTC)
Re: [Scheme-reports] digit-value Alaric Snell-Pym (03 Jul 2012 08:50 UTC)
Re: [Scheme-reports] digit-value Pierpaolo Bernardi (03 Jul 2012 09:11 UTC)
Re: [Scheme-reports] digit-value John Cowan (03 Jul 2012 14:45 UTC)
Re: [Scheme-reports] digit-value Pierpaolo Bernardi (03 Jul 2012 15:58 UTC)
Re: [Scheme-reports] digit-value John Cowan (04 Jul 2012 04:22 UTC)
(missing)
Re: [Scheme-reports] digit-value John Cowan (05 Jul 2012 02:25 UTC)
Re: [Scheme-reports] digit-value John Cowan (03 Jul 2012 03:19 UTC)

Re: [Scheme-reports] digit-value John Cowan 03 Jul 2012 03:19 UTC

Marc Feeley scripsit:

> Your arguments suggest to me that string->number should be extended to
> Unicode (if that's supported by the implementation), and digit-value
> dropped from the standard.

Once more, where do we stop?  If `string->number` gets support,
why not `read`?  If `read` gets support, why not numeric literals?
No programming language I know of, indeed no implementation I know of,
goes so far as to support non-European digits in its numeric literals.
That's going well beyond anything we have precedent for.

The WG needed to redefine `char-numeric?` because the R6RS definition,
while basically sound, referred to a Unicode character class "Numeric"
that doesn't exist, and nobody noticed, not even me.  :-)  The WG settled
that it returns `#t` on Unicode's decimal digits only.  Given that,
it makes sense to be able to ask for the value of those decimal digits
as well.  That is already going where no Scheme has gone before, something
the WG has tried to avoid.

--
John Cowan   <cowan@ccil.org>   http://www.ccil.org/~cowan
One time I called in to the central system and started working on a big
thick 'sed' and 'awk' heavy duty data bashing script.  One of the geologists
came by, looked over my shoulder and said 'Oh, that happens to me too.
Try hanging up and phoning in again.'  --Beverly Erlebacher

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