Merge pull request #77 from Romanx/feat/ListValuesByIndex

Feature: List Values by Index
jdiamond · Jul 9, 2014 · bdd6f8c · bdd6f8c
2 parents 957a95f + f379e9b
commit bdd6f8c
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Showing 3 changed files with 66 additions and 1 deletion.
diff --git a/Nustache.Core.Tests/Describe_ValueGetter.cs b/Nustache.Core.Tests/Describe_ValueGetter.cs
@@ -152,6 +152,27 @@ public void It_gets_XmlNode_multiple_child_element_values_as_a_list()
             Assert.AreEqual("text2", elements[1].InnerText);
         }
 
+        [Test]
+        public void It_gets_ListValueByIndex_values_from_array()
+        {
+            string[] target = new[] { "hello", "world" };
+            Assert.AreEqual("hello", ValueGetter.GetValue(target, "0"));
+        }
+
+        [Test]
+        public void It_gets_ListValueByIndex_values_from_List()
+        {
+            List<string> target = new List<string>() { "hello", "world" };
+            Assert.AreEqual("hello", ValueGetter.GetValue(target, "0"));
+        }
+
+        [Test]
+        public void It_fails_ListValueByIndex_values_from_List()
+        {
+            string[] target = new[] { "hello", "world" };
+            Assert.AreEqual(ValueGetter.NoValue, ValueGetter.GetValue(target, "2"));
+        }
+
         public class ReadWriteInts
         {
             public int IntField = -1;

diff --git a/Nustache.Core/ValueGetter.cs b/Nustache.Core/ValueGetter.cs
@@ -226,6 +226,22 @@ public override object GetValue()
         }
     }
 
+    internal class ListValueByIndexGetter : ValueGetter
+    {
+        private readonly IList _target;
+        private readonly int _index;
+
+        public ListValueByIndexGetter(IList target, int index)
+        {
+            _target = target;
+            _index = index;
+        }
+        public override object GetValue()
+        {
+            return _target[_index];
+        }
+    }
+
     internal class NoValueGetter : ValueGetter
     {
         public override object GetValue()

diff --git a/Nustache.Core/ValueGetterFactory.cs b/Nustache.Core/ValueGetterFactory.cs
@@ -85,7 +85,8 @@ public static class ValueGetterFactories
             new DictionaryValueGetterFactory(),
             new MethodInfoValueGatterFactory(),
             new PropertyInfoValueGetterFactory(),
-            new FieldInfoValueGetterFactory()
+            new FieldInfoValueGetterFactory(),
+            new ListValueByIndexGetterFactory()
         };
 
         public static ValueGetterFactoryCollection Factories
@@ -247,4 +248,31 @@ private static Type GetSupportedInterfaceType(Type targetType)
             }
         }
     }
+
+    internal class ListValueByIndexGetterFactory : ValueGetterFactory
+    {
+        public override ValueGetter GetValueGetter(object target, Type targetType, string name)
+        {
+            //Both Lists and Arrays internally can be assigned to IList.
+            if (typeof(IList).IsAssignableFrom(targetType))
+            {
+                var listTarget = target as IList;
+                int arrayIndex;
+                bool parseSuccess = Int32.TryParse(name, out arrayIndex);
+
+                /* 
+                 * There is an index as per the success of the parse, it is not greater than the count 
+                 * (minus one since index is zero referenced) or less than zero.
+                 */ 
+                if(parseSuccess &&
+                   !(arrayIndex > (listTarget.Count - 1)) &&
+                   !(arrayIndex < 0))
+                {
+                    return new ListValueByIndexGetter(listTarget, arrayIndex);
+                }
+            }
+
+            return null;
+        }
+    }
 }