On Thursday, 5 December 2013 at 18:26:48 UTC, Jonathan M Davis
wrote:
To be fair, you can't solve the problem automatically. It's
fundamentally
wrong to compare signed and unsigned values, and doing either
the conversion
to unsigned or to signed could be wrong (or both could be
wrong), depending on
the values.
*Actually*... that's not exactly true.
std.algorithm.max and std.algorithm.min actually do it perfectly
well.
It is completely feaseable to imagine having an:
std.functional.less(T, U)(T t, U u){}
Which could work for *any* (compatible) type, including those
with mixed signed-ness.
The only "issue" is that if the signs *are* mixed, the comparison
is a *bit* more costly. It involved *two* comparisons, and a
boolean condition:
https://github.com/D-Programming-Language/phobos/blob/ab34fb92addca61755474df04a0d0d6e0f1148a2/std/algorithm.d#L6698
Truth be told, "a < b" could work correctly 100% of the time, no
question asked, if the *language* wanted to. The (2) problems
would be:
1) Breaks backward compatibility with C and C++.
2) Higher (and hidden) comparison costs.
Try to convince Walter that these are worth it XD !
