EReturn
The main idea behind this simple API is providing safe function result.
Usage
Every Function should yields a value with type return:result/0:
-type result() :: ok() | ok_result() | error().
-type ok() :: 'ok'.
-type ok_result() :: {'ok', term()}.
-type error() :: {'error', {reason(), error_parameters()}}.
-type reason() :: atom().
-type error_parameters() :: [] | [error_parameter()].
-type error_parameter() :: {atom(), term()}.
Example
Suppose i have a module named api.erl:
-module(api).
-export([func_1/0
,func_2/0
,func_3/0
,func_4/1
,func_5/1]).
%% Include return's header file and use its macros:
-include("/path/to/return/include/return.hrl").
-spec func_1() -> return:ok().
func_1() ->
...
?ok. %% means 'ok'
-spec func_2() -> return:ok_result().
func_2() ->
...
?ok(foo). %% {'ok', foo}
-spec func_3() -> return:ok() | return:error().
func_3() ->
case ... of
true ->
?ok;
false ->
?err(reason_of_error) %% {'error', {reason_of_error, []}}
end.
-spec func_4(term()) -> return:ok_result() | return:error().
func_4(Arg) ->
case ... of
Value when ... ->
?ok(Value); %% {'ok', Value}
_ ->
?err(reason_of_error, [{argument, Arg}])
%% {'error', {reason_of_error, [{argument, Arg}]}}
end.
-spec func_5(term()) -> return:result().
func_5(Arg) ->
try ... of
Value when ... ->
?ok(Value);
_ ->
?ok
catch
_:Reason ->
?err(crash, [{reason, Reason}, ?stacktrace, ?module, ?function, {arguments, [Arg]}])
%% {error, {crash, [{reason, Reason}
%% ,{stacktrace, erlang:get_stacktrace()}
%% ,{module, ?MODULE}
%% ,{function, ?FUNCTION_NAME}
%% ,{arguments, [Arg]}]}}
end.Note that reason() must be atom() and error_parameters() must be a proplist, otherwise it exits with reason like {parameter_type, ...}.
