From f3222e361bbc28d3c3922f99c22a44d44c6914c0 Mon Sep 17 00:00:00 2001
From: Sebastian Messmer <mail@smessmer.de>
Date: Fri, 26 Jun 2015 02:17:08 +0200
Subject: [PATCH] Added operator<<(ostream, Either)

---
 either.h            | 13 ++++++++++---
 test/EitherTest.cpp | 14 ++++++++++++++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/either.h b/either.h
index 87ae08c4..bc07297c 100644
--- a/either.h
+++ b/either.h
@@ -67,9 +67,6 @@ namespace cpputils {
 
         //TODO fold, map_left, map_right, left_or_else(val), right_or_else(val), left_or_else(func), right_or_else(func)
 
-        //TODO Test operator<<
-        //TODO operator<<(ostream)
-
         bool is_left() const {
             return _side == Side::left;
         }
@@ -167,6 +164,16 @@ namespace cpputils {
         return !operator==(lhs, rhs);
     }
 
+    template<class Left, class Right>
+    std::ostream &operator<<(std::ostream &stream, const Either<Left, Right> &value) {
+        if (value.is_left()) {
+            stream << "Left(" << value.left() << ")";
+        } else {
+            stream << "Right(" << value.right() << ")";
+        }
+        return stream;
+    }
+
     //TODO Test make_either<>
     //TODO make_either<>
 }
diff --git a/test/EitherTest.cpp b/test/EitherTest.cpp
index 91470547..2b0697b4 100644
--- a/test/EitherTest.cpp
+++ b/test/EitherTest.cpp
@@ -3,9 +3,11 @@
 #include <boost/optional/optional_io.hpp>
 #include "../either.h"
 #include "../macros.h"
+#include <sstream>
 
 //TODO Go through all test cases and think about whether it makes sense to add the same test case but with primitive types.
 
+using std::ostringstream;
 using std::string;
 using std::vector;
 using namespace cpputils;
@@ -295,6 +297,18 @@ TEST_F(EitherTest, LeftNotEqualsRight) {
   EXPECT_FALSE(val2 == val1);
 }
 
+TEST_F(EitherTest, OutputLeft) {
+  ostringstream str;
+  str << Either<string, int>("mystring");
+  EXPECT_EQ("Left(mystring)", str.str());
+}
+
+TEST_F(EitherTest, OutputRight) {
+  ostringstream str;
+  str << Either<int, string>("mystring");
+  EXPECT_EQ("Right(mystring)", str.str());
+}
+
 class DestructorCallback {
 public:
   MOCK_CONST_METHOD0(call, void());