Denis Koroskin wrote:
On Fri, 27 Feb 2009 16:44:31 +0300, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> wrote:
Michel Fortin wrote:
On 2009-02-27 04:43:46 -0500, bearophile <bearophileh...@lycos.com>
said:
D2 supports the interval syntax in the foreach:
foreach (i; 1..1000) {...}
Such intervals are useful in a very large number of situations. So,
with the new Range support, it may be useful to allow the interval
syntax to be used in other contexts as well.
So x..y may become a first-class lazy interval from x to y-1, that
can be passed to functions too, etc, and not just used into foreach
(the compiler can recognize it, and often optimize it away in many
situations, replacing it with a normal for() loop).
I agree that having first-class intervals in the language would make
it better, especially when you want to pass intervals as function
arguments.
I'm having trouble understanding what's wrong with the good old data
types and functions.
Andrei
The syntax. One may want to reuse 0..100 syntax to generate random number:
auto x = random(0..100); // gimme a random value in [0, 100)
or check if a value belongs to an interval:
T opIndex(size_t index)
{
assert(index in 0.._size);
// ...
}
Particularly, multi-dimensional slices. We have opSlice as a hacky
special case of opIndex. So desirable syntax like
auto y = x[2..$, 4, 3..8];
is impossible. You can only do something like:
auto y = x[Range(2,$), 4, Range(3,8)];
or perhaps
auto y = x[Range[2..$], 4, Range[3..8]];
