penny distribution

[Batista, Facundo]

austin at smartobject.biz wrote:

#- Let me try another way of saying this.  A number with a small number
#- of decimal places is equivalent to an integer, as was pointed out
#- before.  People don't expect division of integers, or multiplication
#- of integers by reals (and I still think the former is a subset of the
#- latter) to yield exact integer answers.  There will obviously be some
#- rounding involved, although some people might want to specify exactly
#- how that rounding takes place.  However, most people expect addition
#- and subtraction of integers to yield exact integer answers.  An
#- itemized invoice that contains percentage taxation or discounting
#- (i.e., most invoices I've seen) enforces some sort of 
#- distributive law
#- on inexact multiplication and exact addition.  A program that
#- generates such an invoice must have some way of adjusting the
#- multiplication to safisfy the distributive law.  Invariably, attempts
#- to adjust addition instead make customers very unhappy.

Get your point. But which side do you adjust? 

I think something like this is not the behaviour expected for a + or a *.

Of course, your point is still valid, but I think that the operation is not
the place to address it.

It's the same with .divideByN: a method that do that, because the standard
division don't. And you don't modify the standard division to return
something like this:

>>> Decimal(5) / 3
(1.66, 1.67, 1.67)

You just don't.

.	Facundo