Re: [Scheme-reports] digit-value

[Pierpaolo Bernardi <olopierpa@x>]

On Tue, Jul 3, 2012 at 10:49 AM, Alaric Snell-Pym
<alaric@x> wrote:

>>> char-numeric? certainly seems to be of limited use without it, but
>>> is the char-numeric?/digit-value pair actually useful at all in the
>>> scope of WG1, given string->number?
>>
>> Unless we are to extend `string->number` to handle non-European
>> digits (and then `read`, and then numeric literals?), I think so.
>>
> Well, if digit-value exists and handles all those fun cases, then I
> think that read (and, therefore by definition, numeric literals), should
> do so too for consistency and to avoid having to have two parallel
> digit->number conversions lurking inside every implementation, one a
> subset of the other.

string->number and read accepting as numbers all characters satisfying
the current char-numeric? would be crazy.

Think roman numerals, just to take a simple example we all know about.
Assuming the I are the right unicode character for the roman numeral 1:

(string->number "II")   ==>  2?  11?

Solving this problem does not belong to a library at this level.

P.

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