From 5fab324af707977a6e08246757acd09e1a3cb7c1 Mon Sep 17 00:00:00 2001
From: Siraaj Khandkar <siraaj@khandkar.net>
Date: Thu, 7 Jul 2016 15:43:56 -0400
Subject: [PATCH] Add hope_option:to_undefined/1

---
 src/hope.app.src           |  2 +-
 src/hope_option.erl        |  6 ++++++
 test/hope_option_SUITE.erl | 18 ++++++++----------
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/src/hope.app.src b/src/hope.app.src
index 16745b5..55dc7e3 100644
--- a/src/hope.app.src
+++ b/src/hope.app.src
@@ -1,7 +1,7 @@
 {application, hope,
  [
   {description, "Higher Order Programming in Erlang"},
-  {vsn, "4.0.0"},
+  {vsn, "4.1.0"},
   {registered, []},
   {applications, [
                   kernel,
diff --git a/src/hope_option.erl b/src/hope_option.erl
index 29836f7..2bd9e7b 100644
--- 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, _) ->
diff --git a/test/hope_option_SUITE.erl b/test/hope_option_SUITE.erl
index d2a73a3..e7d14dc 100644
--- a/test/hope_option_SUITE.erl
+++ b/test/hope_option_SUITE.erl
@@ -9,7 +9,7 @@
 %% Test cases
 -export(
     [ t_of_result/1
-    , t_of_undefined/1
+    , t_undefined/1
     , t_put/1
     , t_get/1
     , t_map/1
@@ -33,7 +33,7 @@ all() ->
 groups() ->
     Tests =
         [ t_of_result
-        , t_of_undefined
+        , t_undefined
         , t_put
         , t_get
         , t_map
@@ -93,14 +93,12 @@ t_pipe(_Cfg) ->
     none      = hope_option:pipe(Steps, 2),
     none      = hope_option:pipe(Steps, 3).
 
-t_of_undefined(_Cfg) ->
-    Foo = foo,
-    Bar = bar,
-    Baz = baz,
-    {some, Foo} = hope_option:of_undefined(Foo),
-    {some, Bar} = hope_option:of_undefined(Bar),
-    {some, Baz} = hope_option:of_undefined(Baz),
-    none        = hope_option:of_undefined(undefined).
+t_undefined(_Cfg) ->
+    X         = foo,
+    {some, X} = hope_option:of_undefined(X),
+    X         = hope_option:to_undefined({some, X}),
+    none      = hope_option:of_undefined(undefined),
+    undefined = hope_option:to_undefined(none).
 
 t_validate(_Cfg) ->
     IsFoo = fun (X) -> X =:= foo end,
-- 
2.20.1