type_spec.erl

-module(test).

-export([ myfunc/1
        , myfunc/2
        ]).

%%Type alias:
type mywtf :: wtf(string, integer, atom).

%%Type constructor:
type wtf(A, B, C) :: {A, B, C} | {[A], [B], [C]} | (C -> A).

type generic_list(A, B) :: [{A, B}].

type fuzzy :: ok | error.
type error :: atom.
type ok :: atom.

myfun :: [A], (A -> B) -> [atom].
myfun(_A, _B) ->
  [ok].

myfun :: mywtf -> atom.
myfun({_A, _B, _C}) ->
  ok.

myfunc :: (ok -> atom) -> (A -> [A]).
myfunc(F) ->
  Atom :: (ok -> atom) = F,
  SomeRandomVar :: fuzzy = case F(amir) of
                             true -> ok;
                             false -> error
                           end,
  io:format("~p: ~p~n", [Atom, SomeRandomVar]),
  fun(A) -> [A] end.

myfunc :: (M, I) -> (atom -> [atom]).
myfunc(_, _) ->
  ok.

map :: (A -> B), [A] -> [B].
map(F, L) ->
  lists:map(F, L).