Steven D'Aprano <[EMAIL PROTECTED]> wrote:
> The less your function does, the more constrained it is, the less
> testing you have to do -- but the less useful it is, and the more work
> you put onto the users of your function. Instead of saying something
> like
> a = MyNumericClass(1)
> b = MyNumericClass(6)
> # more code in here...
> # ...
> result = f(a, b)
> you force them to do this:
> a = MyNumericClass(1)
> b = MyNumericClass(6)
> # more code in here...
> # ...
> # type-cast a and b to keep your function happy
> result = f(int(a), int(b))
> # and type-cast the result to what I want
> result = MyNumericClass(result)
I have a question for you. Consider this function:
def f(n):
"""Return the largest natural power of 2 which does not exceed n."""
if n < 1:
raise ValueError
i = 1
while i <= n:
j = i
i *= 2
return j
If I pass it an instance of MyNumericClass, it will return an int or a
long, not an instance of MyNumericClass.
In your view, is this a weakness of the implementation? Should the
author of the function make an effort to have it return a value of the
same type that it was passed?
-M-
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