Re: [Scheme-reports] digit-value

[John Cowan <cowan@x>]

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@x>   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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