On Wednesday, 16 February 2022 at 15:55:55 UTC, bachmeier wrote:
On Wednesday, 16 February 2022 at 15:21:11 UTC, jmh530 wrote:
On Tuesday, 15 February 2022 at 22:24:53 UTC, bachmeier wrote:
[snip]
After looking at the documentation and seeing
CommonType!(int, uint) is uint, I have to say that iota's
behavior doesn't make much sense.
What do you propose as an alternative? What about the
narrowest type that fits both int and uint? That would be a
long.
My preference (in order)
1. Change everything to long. That way it works as anyone other
than the author of std.range.iota would expect.
2. Throw an error when casting from signed to unsigned. That
would at least prevent wrong output. The current behavior
delivers incorrect output 100% of the time, excluding the
trivial case where the correct output has zero elements.
3. Require the step to be positive.
4. Remove iota from Phobos because it silently changes correct
code to incorrect code that compiles and runs.
I've got an idea for combining 1 and 2.
Step 1: In the integral overloads, use allSatisfy!(isSigned, B,
E) || allSatisfy!(isUnsigned, T, U) for the current behavior
Step 2: When !(allSatisfy!(isSigned, B, E) ||
allSatisfy!(isUnsigned, T, U)), then convert to narrowest common
type as I mentioned (long in your case).
This would preserve the current size when the types are both
either signed or unsigned and then would expand it only when
there are different signed-ness. This also makes the behavior
change at compile-time instead of throwing at runtime.
