PEP 327: Decimal Data Type

[Aahz]

In article <qeq520pv7kbd1s3ojmn3idetjuljhtk5md at 4ax.com>,
Stephen Horne  <steve at ninereeds.fsnet.co.uk> wrote:
>On 5 Feb 2004 09:18:12 -0500, aahz at pythoncraft.com (Aahz) wrote:
>>In article <ad052e5c.0401310101.1c5bd5aa at posting.google.com>,
>>Dan Bishop <danb_83 at yahoo.com> wrote:
>>>
>>>For money, it means that I have *exactly* $1.80.  This is because
>>>"dollars" are just a notational convention for large numbers of cents.
>>> I can just as accuately say that have an (integer) 180 cents, and
>>>indeed, that's exactly the way it would be stored in my financial
>>>institution's database.  (I know because I used to work there.)  So
>>>all you really need here is "int".  But I do agree with the idea of
>>>having a class to hide the decimal/integer conversion from the user.
>>
>>Really.  What kind of financial institution was this?  They didn't need
>>to deal with any form of fractional pennies?
>
>Does it really matter if they did? They may not deal in whole pennies,
>but I seriously doubt that they need infinite precision - integers
>with a predefined scaling factor (ie fixed point arithmetic) will, I
>suspect, handle those few jobs that counting in pennies can't.

That's mostly true (witness Tim Peters's FixedPoint.py).  If you really
want to debate this issue, read Cowlishaw first:
http://www2.hursley.ibm.com/decimal/decarith.html
-- 
Aahz (aahz at pythoncraft.com)           <*>         http://www.pythoncraft.com/

"The joy of coding Python should be in seeing short, concise, readable
classes that express a lot of action in a small amount of clear code -- 
not in reams of trivial code that bores the reader to death."  --GvR