[Python-Dev] Fixed-point numeric type

[Tim Peters]

[Kevin Jacobs]
> I'm finding that this is a problem in education, not desire.  Once you
> educate developers, they will demand decimal types.  Unfortunately, I've
> found that many db developers are completely ignorant of the
> caveats of both fixed and floating point arithmetic.  They naively "just
> want things to work" and aren't too worried about the details or the
> corner-cases.  (I blame this on the cruddy computer science content of
> many CIS degree programs, but that is a topic for a different rant.)

Or they have a COBOL background.  COBOL has always supported decimal
arithmetic, and it can be hard to get across to a COBOL'er that getting the
pennies right can be a problem in other languages.  It's part of the air
they breathe, beneath conscious attention.

> Nevertheless, I would like to seeing proper fixed point support in the
> Python standard library

What does "proper" mean?  The implementation of FixedPoint was easy for me,
but getting users to spell out what they really needed proved impossible.
"Proper" isn't a specification all by itself <wink>.

> with integration advise in a DB-API extension standard or PEP.  As it
> is, our applications patch many of the DB-API modules to add support
> for our own homebrew decimal types, and it is fairly cumbersome to
> maintain.

Is FixedPoint usable for you?  This person seemed to think it helped:

http://mailman.tux4web.de/pipermail/orm-devel/2002-December/000083.html

"""
  o I've created a numeric datatype and a numericColumn. They use the
    FixedPoint module you can find at

       http://fixedpoint.sourceforge.net/html/lib/module-FixedPoint.html

    This lets you use arbitrary precision/exact math just like pgsql
    does internally.
"""