Well, that’s to be expected - the implementation of map expects a function that takes ownership of its inputs, so you get a type mismatch.
If you really want to golf things, you can tack your own map_ref (and friends) onto the Iterator trait. It’s not very useful - the output can’t reference the input - but it’s possible!
I imagine you could possibly extend this to a combinator that returns a tuple of (Input, ref_map'd output) to get around that limitation, although I can’t think of any cases where that would actually be useful.
Except when Type::Method takes a reference, then it doesn't just work
Well, that’s to be expected - the implementation of
mapexpects a function that takes ownership of its inputs, so you get a type mismatch.If you really want to golf things, you can tack your own
map_ref(and friends) onto theIteratortrait. It’s not very useful - the output can’t reference the input - but it’s possible!I imagine you could possibly extend this to a combinator that returns a tuple of
(Input, ref_map'd output)to get around that limitation, although I can’t think of any cases where that would actually be useful.