From f2e1fffc2e9ce505ae1891a2251ae2036ed13422 Mon Sep 17 00:00:00 2001
From: Siraaj Khandkar <siraaj@khandkar.net>
Date: Mon, 22 Dec 2014 16:35:06 -0500
Subject: [PATCH] Implement hope_option:of_undefined/1

---
 src/hope.app.src           |  2 +-
 src/hope_option.erl        |  6 ++++++
 test/hope_option_SUITE.erl | 11 +++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/hope.app.src b/src/hope.app.src
index 6446af5..e8f8be9 100644
--- a/src/hope.app.src
+++ b/src/hope.app.src
@@ -1,7 +1,7 @@
 {application, hope,
  [
   {description, "Higher Order Programming in Erlang"},
-  {vsn, "1.8.0"},
+  {vsn, "1.9.0"},
   {registered, []},
   {applications, [
                   kernel,
diff --git a/src/hope_option.erl b/src/hope_option.erl
index 180c416..529158d 100644
--- a/src/hope_option.erl
+++ b/src/hope_option.erl
@@ -14,6 +14,7 @@
     , iter/2
     , pipe/2
     , of_result/1
+    , of_undefined/1
     ]).
 
 
@@ -65,3 +66,8 @@ pipe([F|Fs], X) ->
     t(A).
 of_result({ok, X})    -> {some, X};
 of_result({error, _}) -> none.
+
+-spec of_undefined(undefined | A) ->
+    t(A).
+of_undefined(undefined) -> none;
+of_undefined(X)         -> {some, X}.
diff --git a/test/hope_option_SUITE.erl b/test/hope_option_SUITE.erl
index 8789d3d..370cf24 100644
--- a/test/hope_option_SUITE.erl
+++ b/test/hope_option_SUITE.erl
@@ -9,6 +9,7 @@
 %% Test cases
 -export(
     [ t_of_result/1
+    , t_of_undefined/1
     , t_put/1
     , t_get/1
     , t_map/1
@@ -31,6 +32,7 @@ all() ->
 groups() ->
     Tests =
         [ t_of_result
+        , t_of_undefined
         , t_put
         , t_get
         , t_map
@@ -88,3 +90,12 @@ t_pipe(_Cfg) ->
     none      = hope_option:pipe(Steps, 1),
     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).
-- 
2.20.1