Add hope_option:to_undefined/1

[hope.git] / src / hope_option.erl

diff --git a/src/hope_option.erl b/src/hope_option.erl
index 29836f7..2bd9e7b 100644 (file)
--- a/src/hope_option.erl
+++ b/src/hope_option.erl
@@ -19,6 +19,7 @@
     , iter/2
     , of_result/1
     , of_undefined/1
+    , to_undefined/1
     , validate/2
     ]).
 
@@ -85,6 +86,11 @@ of_result({error, _}) -> none.
 of_undefined(undefined) -> none;
 of_undefined(X)         -> {some, X}.
 
+-spec to_undefined(t(A)) ->
+    undefined | A.
+to_undefined(none)      -> undefined;
+to_undefined({some, X}) -> X.
+
 -spec validate(t(A), fun((A) -> boolean())) ->
     t(A).
 validate(none, _) ->