On 03/02/2012 01:08 PM, Andrej Mitrovic wrote:
> Is there a reason why there's no .empty property for hashes? std.array
> defines it for arrays, and range types must have it defined.
Yes, empty is a part of the InputRange interface. Slices are InputRange
ranges but associative arrays are not. Unless they also provide front,
which would returns a tuple of key and value I guess, and popFront()
which would remove that key and value.
But things get interesting again because implementing empty, front, and
popFront() on the AA interface would conflate the collection with a range.
A better approach might be to continue using byKey() and byValue(),
which are ranges and follow the recent proposal of byPair(). (I can't
locate the thread for that. (?))
> But
> hashes are left out even though they define .length. This could be put
> in std.array:
>
> @property bool empty(T)(in T a)
> if (isAssociativeArray!T)
> {
> return !a.length;
> }
>
> I can't mark it as neither pure, nothrow, nor safe. I guess that's an
> implementation detail at this point.
Ali
