On Fri, 27 Apr 2012 12:37:41 -0400, Joseph Rushton Wakeling
<[email protected]> wrote:
I have to say I'm somewhat confused about whether the pure markings are
really accurate. The reputation() modifies the reputationUser_ and
reputationObject_ internal arrays and hence the returned values of
reputationUser() and reputationObject(). It's true that for a given
input to reputation(), the outcome will always be the same, but there's
nevertheless mutability involved: if I pass one input to reputation(),
and then another, the reputationObject() and ...User() outputs will
change as a result.
weak purity, I think, is one of the most revolutionary ideas to come from
D. Essentially, we get compiler-checked pure functions that can be
written imperatively instead of functionally.
If the function is weakly pure, then it cannot be optimized based on
purity, so I don't think there is any way marking it pure *hurts*.
-Steve
