On Monday, 8 June 2015 at 01:15:30 UTC, Mike Parker wrote:
I know how to use a range :) What I'm asking about is a
requirement on implementing front on a custom range. Is there a
rule that says when I implement my own range, consecutive calls
to front must return the same value until popFront is called?
Example:
Is this a valid implementation of front?
auto front() { return _member++; }
Or must it be this:
auto front() { return _member; }
void popFront() { ++_member; }
My current understanding is that the former is incorrect, but
I'm looking for confirmation of that. I can't find it written
down anywhere.
Here is how it is implemented in the book of Andrew:
@property bool empty(T)(T[] a) { return a.length == 0; }
@property ref T front(T)(T[] a) { return a[0]; }
void popFront(T)(ref T[] a) { a = a[1 .. $]; }
