A modest PEP0238 suggestion

Chris Barker chrishbarker at home.net
Wed Jul 25 19:36:04 CEST 2001

Guido van Rossum wrote:

>Changing 1/2
> from returning a float to returning a rational won't have to break
> code, since the mathematical value of the result is the same.

No, it's not. We should all be aware now that 1/10 as a rational is not
the same value as 1/10 stored as binary floating point. After all, how
many times does someone post a question about why a loop like the
following doesn't terminate?

>>> i = 0.
>>> while i <> 1:
...     i+=0.1

Anyway, while the difference is far more subtle, and far less likely to
break code, a rational is NOT a float (nor is a float a real, so I'm
glad you didn't name them that). And there are a few of us that
occasionally make use of or at least accomodate the difference (not to
mention performance issues!)


Christopher Barker,
ChrisHBarker at home.net                 ---           ---           ---
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