Difference between protocol & behaviour in elixir

Question

Behaviours define callbacks & protocols define methods without signatures. Modules implementing a protocol should give definition for all those methods. Same for modules

Answer 1

Protocol is type/data based polymorphism. When I call Enum.each(foo, ...), the concrete enumeration is determined from the type of foo.

Behaviour is a typeless plug-in mechanism. When I call GenServer.start(MyModule), I explicitly pass MyModule as a plug-in, and the generic code from GenServer will call into this module when needed.