On Thursday, 17 August 2023 at 09:28:05 UTC, Joel wrote:
.map!(std.uni.toLower) .sort!"a<b" .writeln; } ```onlineapp.d(8): Error: none of the overloads of template `std.algorithm.sorting.sort` are callable using argument types `!("a<b")(MapResult!(toLower, ByCodeUnitImpl))` /dlang/dmd/linux/bin64/../../src/phobos/std/algorithm/sorting.d(1925): Candidate is: `sort(alias less = "a < b", SwapStrategy ss = SwapStrategy.unstable, Range)(Range r)`with `less = "a<b", ss = SwapStrategy.unstable, Range = MapResult!(toLower, ByCodeUnitImpl)` must satisfy one of the following constraints: ` hasSwappableElements!Range hasAssignableElements!Range ss != SwapStrategy.unstable`
`map` generates a range `r` whose elements can be accessed by mutable reference only if the result of calling the map function (on a source element) is a mutable reference. But `std.uni.toLower` returns by value, and `sort` requires `r.front` to be a mutable reference.
I'll look at improving the docs.
