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Rust could generate a bespoke internal proxy type.
by the_mitsuhiko 9y ago
Rust could generate a bespoke internal proxy type.
- Rusky 9y agoThat would still require dynamic dispatch of some kind.
- the_mitsuhiko 9y agoBut it wouldn’t require a heap allocation.
- lmm 9y agoWhere is the proxy implementation going to go if not the heap?
- GolDDranks 9y agoThe proxy object would have statically known size (maximum of the size of the types it dispatches between, plus some metadata such as a vtable pointer or an enum discriminant). Now, because you know the size statically, you can store it in the stack.
- shepmaster 9y agoUntil then, we use `Either` (https://stackoverflow.com/a/50204370/155423 https://stackoverflow.com/a/50204370/155423)
- leshow 9y agoTangentially, do you know why Rust never included an Either type? We have Result, which is great, but Either is useful for more things than errors (though that seems to be it's main use).
- steveklabnik 9y agoWe had it for a long time, as well as result, and literally no code used it, so we took it out. There’s a crate on crates.io for it if you want to use it for something.