It basically steps through in a stride and sets the checkpoints
to false.
C++:
template <typename /*RandomAccessIterator*/ It, int /*Integer*/ N>
void mark(It begin, It end, N step) {
assert(begin != end)
*begin = false;
while (end - begin > step) {
begin = begin + step;
*begin = false;
}
}
For D this is what I figured would be the way?
void mark(R, N)(auto ref R range, N step)
if (
/* 1 */ isIntegral!N
/* 2 */ && isRandomAccessRange!R
/* 3 */ && is(ElementType!R == bool)
/* 4 */ && hasAssignableElements!R
) {
range.front = false;
while (!range.empty) {
range.popFrontN(N);
range.front = false;
}
}
I have a more specific question too:
1) I've seen some phobos code checking for assignability like
this:
is(typeof(range.front = false))
... is that an advantage of that over hasAssignableElements? Or
is that just basically combining constraints 3 and 4 which I have
above?
2) Say I wanted to restrict to only lvalue ranges passed in as
inputs. Does that mean I use hasLvalueElements as a constraint or
is remove the "auto" and just have a ref parameter sufficient?
Cheers
