[Python-Dev] Python and the Unicode Character Database

[Stephen J. Turnbull]

Lennart Regebro writes:
 > On Tue, Nov 30, 2010 at 09:23, Stephen J. Turnbull <stephen at xemacs.org> wrote:
 > > Sure you can.  In Python program text, all keywords will be ASCII
 > 
 > Yes, yes, sure, but not the contents of variables,

Irrelevant, you're not converting these to a string representation.
If you're generating numerals for internal use, I don't see why you
would want to do arithmetic on them; conversion is a YAGNI.  This is
only interesting to allow naive users to input in a comfortable way.

As yet there is no evidence that there are *any* such naive users, 1.3
billion of "possibles" are shut out, and at least two cultures which
use non-ASCII numerals every day, representing 1.3 billion naive users
(the coincidence of numbers is no coincidence), have reported that
nobody in their right mind would would *input* the numbers that way,
and at least for Japanese, the use cases are not really numeric anyway.

 > > I see no reason not to make a similar promise for numeric literals.
 > 
 > Wait what, literas?

Sorry, my bad.
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 > Why would this be a problem:
 > 
 > >>> T1234 = float('~~~~.~~')
 > >>> T1234
 > 1234.56
 > 
 > But this OK?
 > 
 > >>> T~~~~ = float('1234.56')
 > >>> T~~~~
 > 1234.56

(Sorry, the Arabic is going to get munged, my mailer is beta and
somebody screwed up.)

Because the characters in the identifier are uninterpreted and have no
syntactic content other than their identity.  They're arbitrary.
That's not true of numerics.

Because that works, but

print(T1234)

doesn't (it prints ASCII).  You can't round-trip, but users will
want/expect that.

Because that works but this doesn't:
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T1000 = float('?.???')

Violates TOOWTDI.

If you're proposing to fix the numeric parsers, I still don't like it
but I could go to -0 on it.  However as Alexander points out and MAL
admits, it's apparently not so easy to do that.