erlang-if-expression.erl

-module(ex_if).
-export([is_42/1, always_true/0]).

% contrived example
is_42(Num) ->
  if
    Num =:= 42 -> true;
    true -> false
  end.

always_true() ->
  if
    false, true  -> nevertrue;
    false; true -> alwaystrue;  % we always evaluate to this one
    true -> alsoalwaystrue      % this never gets matched because the previous guard is always true
  end.

%----- ERLANG SHELL -----%
1> c(ex_if).
ex_if.erl:13: Warning: the guard for this clause evaluates to 'false'
ex_if.erl:15: Warning: this clause cannot match because a previous clause at line 14 always matches
{ok,ex_if}     

2> ex_if:is_42(42).
true

3> ex_if:is_42(not42).
false

4> ex_if:always_true().
alwaystrue