ereturn

Ereturn is a parse transform tool that provides ability to return function result from almost any expression in the function clause like return statement in other imperative languages.

Using

Call function erlang:return/1 with return value as the only parameter. The erlang:return/1 function may be imported into local scope for easier use with -import(erlang, [return/1]). module attribute if there is no return/1 function declaration in local scope.

Example

Using this tool you can write code like this:

-module(example).

-export([extract_num/1]).

-import(erlang, [return/1]).
-compile([{parse_transform, ereturn}]).


extract_num(Val) ->
    io:format("common part of the my_fun/1\n"),
    Num = case Val of
              {int, Int} ->
                  Int;
              {float, Float} ->
                  Float;
              _ ->
                  return({error, bad_param})
          end,
    io:format("value is number\n"),
    Num.

Under the hood

Ereturn makes expression containing erlang:return/1 call last in the function clause injecting the remaining expressions into non-returning clauses of the last expression if those exist. The resulting code can be examined using either -compile(['E']). or erlc -E parameter.