I've seen that now this handy code is allowed:
#![feature(inclusive_range_syntax)]
fn main() {
for b in 0u8 ... 255u8 {
println!("{}", b);
}
for bc in b'a' ... b'z' {
print!("{} ", bc as char);
}
println!("");
}
(Some languages prefer to denote inclusive ranges with a syntax like "..>" or similar, to better distinguish it visually from the ".." syntax).
But I'd also like to avoid casts:
#![feature(inclusive_range_syntax)]
fn main() {
for c in 'a' ... 'z' {
print!("{} ", c);
}
println!("");
}
Is it planned to support this too?
Thank you for your answer. The RFC says:
'a'..'{' is equivalent to the inclusive range 'a'...'z': there's absolutely no reason that { is after z other than a quirk of the representation.
But in that page I can't see an answer to my question, if the support for 'a'...'z' is planned.
As you may already know, ranges of chars are tricky because not all 32-bit values represent valid Unicode characters. Because of this, char does not implement the Add trait which is required by the Iterator implementation for RangeInclusive.
The char-iter crate has a custom iterator which contains the necessary logic, so you can write:
for c in char_iter::new('a', 'z') {
// ...
}
The Add trait is used only in the implementation of RangeInclusive::size_hint. Specialization might make it possible to provide an impl that only requires the Step trait (which isn’t implemented by char but could be), and add the size_hint only for types that implement Add.
3 Likes