[Python-Dev] Money module

[Raymond Hettinger]

[Facundo]
> The pre-PEP is almost done, and the corresponding
> test cases are all written.

What is the part about the pre-PEP?  Something like this probably
shouldn't go in the standard library until it has been proven in the
field.  This doubly true for a module that has made some unusual OO
design choices and has an unconventional decomposition of financial
functions.  

* The exchange rate mechanism may end-up not being workable as it does
not incorporate rate changes over time, differing forward and reverse
rates, non-linear factors such as commission/fees, source currency, or
multiple suppliers.

* Time value of money computations are typically dimensionless (not
sensitive to currency type or formatting) and they often have algorithm
specific rounding needs (round at the end of compounding period or each
year or only at the end).

* The absence of a division operator may prove problematic for
allocation routines.

* Usually numeric formatting is kept independent from the rest of the
design.  It will be interesting to see how workable it is to make it
part of the Context object.  In Excel for instance, formatting is a
property of some part of the hierarchy of worksheet, row or column, or
specific cell.  It is not linked to the context for mathematical
operations.

While the Money module remains experimental, it should remain a
third-party package.



Raymond