Rainer Deyke wrote: > Daniel Keep wrote: >> On the basis of how I understand pure to be implemented in D at the >> moment, it is impure. Purity only considers the bits passed on the >> stack. If the reference points to the same location in memory, it's >> considered the same argument. > > As I understand it, D doesn't attempt to do general memoization anyway > (and indeed, shouldn't). Given a reference to an object, if the > reference itself is not modified from one dynamic cast to another, then > the result of the former cast can be reused for the latter.
Which is memoisation, more or less. > The > existence of the reference prevents the object from being > garbage-collected, and manual deletion results in undefined behavior. http://digitalmars.com/d/2.0/expression.html#DeleteExpression Doesn't actually specify whether this case is kosher or not. I suppose that makes it undefined behaviour, although possibly not in quite the same way. :)
