What actually checks for for defimpl in Elixir?

Question

Does "for" always check the type of the first argument in each function defined in the protocol?

EDIT (rephrasing): When a protocol method has only one argument, the implementation is determined based on the type of that single argument (direct or Any). When a protocol method has several arguments, which one is used to find the appropriate implementation? Is it always the first? Can I change it?

Answer 1

Implementation is always determined based on the first argument.

, . def , , .

, , ( t), ( t impl_for!, , ).

A defimpl , , defprotocol. , , .

Answer 2

, for , . , , , Elixir , . , , Any . , , , .

, :

https://github.com/elixir-lang/elixir/blob/150a8a1dcd3610d5ff875e00a1c8779894456ca6/lib/elixir/lib/protocol.ex#L522 https://github.com/elixir-lang/elixir/blob/150a8a1dcd3610d5ff875e00a1c8779894456ca6/lib/elixir/lib/protocol.ex#L456

, - , .

28 .ex, , , : https://github.com/elixir-lang/elixir/blob/150a8a1dcd3610d5ff875e00a1c8779894456ca6/lib/elixir/lib/protocol.ex#L28

, , . .