From 54a17fb005d2d93cf4c8293177085f20f6bbd447 Mon Sep 17 00:00:00 2001
From: Ayoub Kaanich <kayoub5@live.com>
Date: Sun, 5 Aug 2018 18:43:17 +0100
Subject: [PATCH] Allow creating enum from their names.

---
 Src/IronPython/Runtime/Types/PythonType.cs | 16 ++++++++++++++++
 Tests/test_enum.py                         | 18 ++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/Src/IronPython/Runtime/Types/PythonType.cs b/Src/IronPython/Runtime/Types/PythonType.cs
index 354cccd4d..247682062 100644
--- a/Src/IronPython/Runtime/Types/PythonType.cs
+++ b/Src/IronPython/Runtime/Types/PythonType.cs
@@ -647,6 +647,22 @@ public PythonType this[params Type[] args] {
             }
         }
 
+        public object this[string member] {
+            get {
+                if (!UnderlyingSystemType.IsEnum) {
+                    throw PythonOps.TypeError("'type' object is not subscriptable");
+                }
+                if (member == null) {
+                    throw PythonOps.KeyError(member);
+                }
+                try {
+                    return Enum.Parse(UnderlyingSystemType, member);
+                } catch (ArgumentException) {
+                    throw PythonOps.KeyError(member);
+                }
+            }
+        }
+
         [SpecialName, PropertyMethod, WrapperDescriptor]
         public static object Get__module__(CodeContext/*!*/ context, PythonType self) {
             PythonTypeSlot pts;
diff --git a/Tests/test_enum.py b/Tests/test_enum.py
index 8dbc9ca68..a613d61a5 100644
--- a/Tests/test_enum.py
+++ b/Tests/test_enum.py
@@ -37,4 +37,22 @@ def test_constructor(self):
             for value in invalid_values:
                 self.assertRaises(ValueError, EnumType, value)
 
+    @skipUnlessIronPython()
+    def test_from_str(self):
+        """check that enum could be constructed from str names"""
+        from IronPythonTest import DaysInt, DaysShort, DaysLong, DaysSByte, DaysByte, DaysUShort, DaysUInt, DaysULong
+        
+        enum_types = [DaysInt, DaysShort, DaysLong, DaysSByte, DaysByte, DaysUShort, DaysUInt, DaysULong]
+
+        for EnumType in enum_types:
+
+            self.assertEqual(EnumType['None'], EnumType.None)
+            self.assertEqual(EnumType['Mon'], EnumType.Mon)
+            self.assertEqual(EnumType['Weekend'], EnumType.Weekend)
+            
+            self.assertRaises(SystemError, lambda: EnumType[DaysInt])
+            self.assertRaises(TypeError, lambda: EnumType[None])
+            self.assertRaises(TypeError, lambda: EnumType[self])
+            self.assertRaises(KeyError, lambda: EnumType['invalid'])
+
 run_test(__name__)