Hidden Features of Erlang [closed]

Answer 1

Not necessarily "hidden", but I don't see this often. Anonymous functions can have multiple clauses, just like module functions, i.e.

-module(foo).
-compile(export_all).

foo(0) -> "zero";
foo(1) -> "one";
foo(_) -> "many".

anon() ->
    fun(0) ->
            "zero";
       (1) ->
            "one";
       (_) ->
            "many"
    end.


1> foo:foo(0).
"zero"
2> foo:foo(1).
"one"
3> foo:foo(2).
"many"

4> (foo:anon())(0).
"zero"
5> (foo:anon())(1).
"one"
6> (foo:anon())(2).
"many"