On Fri, 03 Sep 2010 11:12:29 -0400, Andrej Mitrovic
<[email protected]> wrote:
I was reading about the various range templates in std.range and I found
this:
http://www.digitalmars.com/d/2.0/phobos/std_range.html#isInfinite
Seems simple enough. But I dont understand it's implementation, this
from range.d:
template isInfinite(Range)
{
static if (isInputRange!Range && is(char[1 + Range.empty]))
enum bool isInfinite = !Range.empty;
else
enum bool isInfinite = false;
}
What does char[1 + Range.empty] do? It looks rather cryptic..
char[1+Range.empty] is a type. If Range.empty is a compile-time constant,
then this type is valid, otherwise it's not valid (the is expression
results to true if the argument is a valid type).
If it's valid, then Range.empty never changes. If it never changes and
it's always false, then it's infinite.
-Steve
