Re: [Modeling-users] Money and Modeling

[Yannick G. <ygi...@yg...>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tuesday 08 July 2003 17:19, you wrote:
> Fixed point doesn't exist in the default python so . You always retrieve
> a numeric but it's map to
> a float in python.  And please be carefull about this as, python do some
> strange round while
> using print() and stuff like that . I got a quick explain here in my
> bookmark but it's in french .
>
>  >>> 6+1
> 7 this is a integer
>  >>> 6.0 + 1
> 7.0  this is a float
>
>  >>> print "%s" % ( 6.0 + 1)
> 7.0
>  >>> print "%d" % ( 6.0 + 1)
> 7

Argh !

  >>> val = 1.1
  >>> val
  1.1000000000000001

I just created a small amount of money from nowhere.  A really small one but 
imprecision of floats adds up and financial controllers really hate when some 
money appears from nowhere...

  >>> 45.678
  45.677999999999997

I just lost a small amount of money in the deep void.  A really small
one but...

How about : 

  class FixedPoint:
     def __init__(self):
        self._val = 0 # int
        self._pointPos = 0 # int too

With a few operators overloaded it would map nicely with the SQL decimal and 
could easily serialize to a simple tuple (like mx.DateTime.tuple())

If it make sense I can send a sketchy class that could be shipped with
Modeling.

- -- 
Yannick Gingras
Coder for OBB : Omniscient Behaviouristic Baroque
http://OpenBeatBox.org
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.7 (GNU/Linux)

iD8DBQE/CtAqrhy5Fqn/MRARAqNyAJ9w3WxZSYiJpQDO1lbWtFSLexBZxwCfWr4T
b96i1XQ5ozrPY8N7UmSn6l4=
=Q7Uf
-----END PGP SIGNATURE-----