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[Python-Dev] PEP 3144 review.

"Martin v. Löwis" martin at v.loewis.de
Mon Sep 28 23:29:42 CEST 2009 
> I would say that there certainly are precedents in other areas for
> keeping the information about the input form around. For example,
> occasionally it would be handy if parsing a hex integer returned an
> object that was compatible with other integers but somehow kept a hint
> that would cause printing it to use hex by default.

At the risk of bringing in false analogies: it seems that Python
typically represents values of some type in their canonical form,
rather than remembering the form in which they arrived in the program:
- integer values "forget" how many preceding zeroes they have
- string literals forget which of the characters had been escaped, and
  whether the string was single- or double-quoted
- floating point values forget a lot more about their literal
  representation (including even the literal decimal value)

I guess a close case would be rational numbers: clearly, 3÷2 == 6÷4;
would a Python library still remember (and repr) the original numerator
and denominator?

Regards,
Martin
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