On 02/03/2011 08:41 AM, Lars T. Kyllingstad wrote:
On Wed, 02 Feb 2011 18:38:02 +0100, spir wrote:
I guess the only solution would be for the compiler to support a kind of
reange type syntax?
I'm not sure I understand what you mean here. Perhaps you're looking for
something like concepts, which have been discussed for both D and C++0x
but rejected in both languages:
http://en.wikipedia.org/wiki/Concept_%28generic_programming%29
Yes, I know about concepts ;-) (and typestates, and such). That's not what I
mean but I could not find how to express it. What I have in mind is a way to
simply express <range of T> just like <array of T> is expressed by "T[]". But
indeed the issue is there is only one type of array of T, while there are an
infinity of types of ranges of T.
Your solution below is a good alternative.
Anyway, if the source and target range are of the same (known) kind,
something like this should work:
struct MyRange(T) { ... }
MyRange!Out map(In, Out)(MyRange!In input, Out delegate(In) f)
{
...
}
If they are of different kinds, but still known, this should work:
struct MySourceRange(T) { ... }
struct MyTargetRange(T) { ... }
MyTargetRange!Out map(In, Out)
(MySourceRange!In input, Out delegate(In) f)
{
...
}
Note that I am only talking about what the compiler should be able to
figure out through IFTI (implicit function template instantiation), and
not about actual implementation.
Right, this is more or less what I was looking for. And I think I can restrict
cases to ranges beeing of the same "kind". If necessary, the result can then be
mapped onto another kind of range (hopefully lazily).
The only "un-workaround-able" situation is, I guess, when the source range is
infinite ;-)
Denis
--
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vita es estrany
spir.wikidot.com
