Fixed the bug when deciding the argument name for positional arguments.

Author: CXuesong

MwParserFromScratch/Nodes/TemplateArgumentCollection.cs

@@ -22,17 +22,18 @@ internal TemplateArgumentCollection(Node owner) : base(owner)
 
         private IEnumerable<KeyValuePair<string, TemplateArgument>> EnumNameArgumentPairs(bool reverse)
         {
-            int index = 1;      // for positional arguments
+            int index = this.Count(arg => arg.Name == null); // for positional arguments
             foreach (var arg in reverse ? Reverse() : this)
             {
                 if (arg.Name == null)
                 {
                     yield return new KeyValuePair<string, TemplateArgument>(index.ToString(), arg);
-                    index++;
+                    index--;
                 }
                 else
                 {
-                    yield return new KeyValuePair<string, TemplateArgument>(MwParserUtility.NormalizeTemplateArgumentName(arg.Name), arg);
+                    yield return new KeyValuePair<string, TemplateArgument>(
+                        MwParserUtility.NormalizeTemplateArgumentName(arg.Name), arg);
                 }
             }
         }

UnitTestProject1/NodeTests.cs

@@ -31,7 +31,16 @@ public void EnumDescendantsTest()
         }
 
         [TestMethod]
-        public void TemplateArgumentsTest()
+        public void TemplateArgumentsTest1()
+        {
+            var root = Utility.ParseWikitext("{{test|a|b}}");
+            var t = root.EnumDescendants().OfType<Template>().First();
+            Assert.AreEqual("a", t.Arguments[1].ToString());
+            Assert.AreEqual("b", t.Arguments[2].ToString());
+        }
+
+        [TestMethod]
+        public void TemplateArgumentsTest2()
         {
             var root = Utility.ParseWikitext("{{\ttest_T  |A=1|B=2|  c\n=3}}");
             var t = root.EnumDescendants().OfType<Template>().First();