On Wed, 12 Jun 2013 22:54:19 -0400, deadalnix <[email protected]> wrote:
On Wednesday, 12 June 2013 at 19:00:28 UTC, Steven Schveighoffer wrote:
Yes, I could introduce it like this:
struct range(inout U) if(is(U == T))
{
size_t length;
U *ptr;
}
but it feels unnecessary. I also find the usage for this solution
clumsy.
Why would you need to do it ? Why not simply do :
class Container(T) {
struct range {
size_t length;
T* ptr;
}
}
if, for instance, I want to accept a container and promise not to modify
the elements, I would have:
void foo(const Container!int cont);
OK, so, in order to access a range of elements from the container, the
container would have some kind of function, like:
range findAll(T elem);
How to mark up this function so it's callable on a const Container?
For C++, their solution (at least for C++03, I haven't checked how this
works for C++11) is to simply define iterator and const_iterator
separately, and then each function is duplicated, one that returns
iterator and one that is const and returns const_iterator.
But I don't like that :) I want to use inout to avoid duplication. I
*also* want to have a function like this:
void processRange(R)(R r) if(isInputRange!R)
And mark up processRange so *it* states that it won't modify the data.
Then I can do:
processRange(cont.findAll(1));
on a mutable C named cont.
Basically, I'm spoiled by how well D slices work :) I want the same power.
-Steve
