[Pymoney-general] Currency's distrib() method

[Facundo B. <fac...@gm...>]

We've been thinking yesterday how the Currency's distrib method should
work.  We figured out three posibilities, but we're not be able to
choose a winner.

The basic idea is to distribute a Currency amount between different
parts, and being sure that you're not losing information (well, money,
;).  But we saw three methods of doing it:

1. Returning the different currencies, splitting almost equally::

    >>> Currency(1).distrib(3)
    [Currency("0.33"), Currency("0.33"), Currency("0.34")]
    >>> Currency(1).distrib(7)
    [Currency("0.14"), Currency("0.14"), Currency("0.14"),
Currency("0.14"), Currency("0.15"), Currency("0.15"),
Currency("0.14")]

The order of the results is not assured. The difference between
max(results) and min(results) will be only one Less significant Digit.


2. Returning the almost exact part, with the rest (a kind of divmod()
but not to integers)::

    >>> Currency(1).distrib(3)
    (Currency("0.33"), Currency("0.01"))
    >>> Currency(1).distrib(7)
    (Currency("0.14"), Currency("0.02"))

If with the original value OV splited in N parts, it returns the
division and the rest (DV, RS), the following applies:  DV * N + RS =3D
OV


3. Returning the different currencies, splitting differently::

    >>> Currency(1).distrib([1,2])
    [Currency("0.33"), Currency("0.67")]
    >>> Currency(3).distrib([2,1,3,3])
    [Currency("0.66"), Currency("0.33"), Currency("1.01"), Currency("1.00")=
]

The rest of the better-possible-division will be assigned to the
greatest(s) value(s) of the result.

What do you think?

.    Facundo

Blog: http://www.taniquetil.com.ar/plog/
PyAr: http://www.python.org/ar/