[phobos] std.array.ilength

[David Simcha]

Hey guys,

Kagamin just came up with a simple but great idea to mitigate the 
pedantic nature of 64-bit to 32-bit integer conversions in cases where 
using size_t doesn't cut it.  Examples are storing arrays of indices 
into other arrays, where using size_t would be a colossal waste of space 
if it's safe to assume none of the arrays will be billions of elements long.

int ilength(T)(T[] arr) {
     assert(arr.length <= int.max);
     return cast(int) arr.length;
}

Usage:

int[] indices;
auto array = returnsArray();
indices ~= array.ilength;

This cuts down on the excessive verbosity of an explicit cast that's 
safe 99.999 % of the time and encourages sprinkling it into code even if 
for the foreseeable future it will be compiled in 32-bit mode.

Two questions:

1.  Is everyone ok with me adding this as a convenience function to 
std.array?
2.  int or uint?  I used int only b/c that was the example on the 
newsgroup, but I think uint makes more sense.

--David Simcha