[LG] Redo the default fallback of namespace

libraries/AdaptiveExpressions/Expression.cs

@@ -734,7 +734,7 @@ public class FunctionTable : IDictionary<string, ExpressionEvaluator>
 #pragma warning restore CA1710 // Identifiers should have correct suffix
 #pragma warning restore CA1034 // Nested types should not be visible
         {
-            private readonly ConcurrentDictionary<string, ExpressionEvaluator> _customFunctions = new ConcurrentDictionary<string, ExpressionEvaluator>(StringComparer.InvariantCultureIgnoreCase);
+            private readonly ConcurrentDictionary<string, ExpressionEvaluator> _customFunctions = new ConcurrentDictionary<string, ExpressionEvaluator>();
 
             /// <summary>
             /// Gets a collection of string values that represent the keys of the StandardFunctions. 

libraries/Microsoft.Bot.Builder.LanguageGeneration/Templates.cs

@@ -452,7 +452,8 @@ private Templates InjectToExpressionFunction()
                 {
                     if (curTemplates.Any(u => u.Name == templateName))
                     {
-                        var newGlobalName = $"{curTemplates.Namespace}.{templateName}";
+                        var prefix = string.IsNullOrWhiteSpace(curTemplates.Namespace) ? string.Empty : curTemplates.Namespace + ".";
+                        var newGlobalName = prefix + templateName;
                         Expression.Functions.Add(newGlobalName, new ExpressionEvaluator(
                             newGlobalName, 
                             (expression, state, options) =>
@@ -648,19 +649,8 @@ private string ExtractNameSpace(IList<string> options)
         {
             var result = ExtractOptionsByKey(_namespaceKey, options);
 
-            if (result == null)
-            {
-                if (Path.IsPathRooted(Source))
-                {
-                    result = Path.GetFileNameWithoutExtension(Source);
-                }
-                else
-                {
-                    throw new Exception("namespace is required or the id should be an absoulte path!");
-                }
-            }
-
-            return result;
+            // If there is no namespace, use the file name parsed from Id.
+            return result ?? Path.GetFileNameWithoutExtension(Id ?? string.Empty);
         }
 
         private IList<string> GetGlobalFunctionTable(IList<string> options)

tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Examples/InjectionTest/injectWithoutNamespace.lg

@@ -0,0 +1,4 @@
+> !# @Exports = greeting
+
+# greeting
+- hi ${name}

tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/Microsoft.Bot.Builder.LanguageGeneration.Tests.csproj

@@ -45,6 +45,7 @@
     <None Remove="Examples\import2.lg" />
     <None Remove="Examples\InjectionTest\common.lg" />
     <None Remove="Examples\InjectionTest\inject.lg" />
+    <None Remove="Examples\InjectionTest\injectWithoutNamespace.lg" />
     <None Remove="Examples\IsTemplate.lg" />
     <None Remove="Examples\LGOptionTest.lg" />
     <None Remove="Examples\MultilineTextForAdaptiveCard.lg" />
@@ -188,6 +189,9 @@
     <Content Include="Examples\InjectionTest\inject.lg">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
+    <Content Include="Examples\InjectionTest\injectWithoutNamespace.lg">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
     <Content Include="Examples\StringInterpolation.lg">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>

tests/Microsoft.Bot.Builder.LanguageGeneration.Tests/TemplatesTest.cs

@@ -1574,6 +1574,35 @@ public void TestInjectLG()
             Assert.Equal("10", evaled.ToString());
         }
 
+        [Fact]
+        public void TestInjectLGWithoutNamespace()
+        {
+            // using Id as the namespace
+            var lgPath = GetExampleFilePath("./InjectionTest/injectWithoutNamespace.lg");
+            var resource = new LGResource("myId", lgPath, File.ReadAllText(lgPath));
+            Templates.ParseResource(resource);
+
+            var (evaled, error) = Expression.Parse("myId.greeting()").TryEvaluate(new { name = "Alice" });
+            Assert.Null(error);
+            Assert.Equal("hi Alice", evaled.ToString());
+
+            // using the fuileName parsed from Id as the namespace
+            resource = new LGResource("./path/myNewId.lg", lgPath, File.ReadAllText(lgPath));
+            Templates.ParseResource(resource);
+
+            (evaled, error) = Expression.Parse("myNewId.greeting()").TryEvaluate(new { name = "Alice" });
+            Assert.Null(error);
+            Assert.Equal("hi Alice", evaled.ToString());
+
+            // With empty id
+            resource = new LGResource(string.Empty, lgPath, File.ReadAllText(lgPath));
+            Templates.ParseResource(resource);
+
+            (evaled, error) = Expression.Parse("greeting()").TryEvaluate(new { name = "Alice" });
+            Assert.Null(error);
+            Assert.Equal("hi Alice", evaled.ToString());
+        }
+
         public class LoopClass
         {
             public string Name { get; set; }