Merge pull request #922 from FirelyTeam/copilot/fix-921

Fix generated C# to correctly attribute functions vs expressions and implement functional DefinitionFilter approach

Author: baseTwo

Cql/CodeGeneration.NET/LibrarySetCSharpCodeGenerator.cs

@@ -258,42 +258,51 @@ private void WriteNamespaceFileScope()
 
         private void WriteMethods()
         {
-            string lastDefinitionType = "";
+            string lastDefinitionRegion = "";
 
             // Assumption: definitions are already sorted by definition type
             foreach (var definition in Definitions)
             {
                 // Assumption: type name will be Cql....Definition
                 Debug.Assert(definition.GetType().Name is { } name && name.StartsWith("Cql") && name.EndsWith("Definition"));
-                string definitionType = definition.GetType().Name["Cql".Length..^"Definition".Length];
+                string definitionRegion =
+                    definition switch
+                    {
+                        // CqlFunctionDefinition is a CqlExpressionDefinition
+                        // We combine them into one region otherwise we would have too many segments switching between Function and Expression
+                        CqlExpressionDefinition => "Functions and Expressions",
+
+                        // Extract the region name from the definition type name e.g. Cql[Parameter]Definition => Parameters
+                        _ => $"{definition.GetType().Name["Cql".Length..^"Definition".Length]}s"
+                    };
 
-                if (lastDefinitionType != definitionType)
+                if (lastDefinitionRegion != definitionRegion)
                 {
-                    if (lastDefinitionType != "")
+                    if (lastDefinitionRegion != "")
                     {
                         IndentedTextWriter.WriteLine($"""
-                                                      #endregion {lastDefinitionType}s
+                                                      #endregion {lastDefinitionRegion}
 
                                                       """);
                     }
 
                     IndentedTextWriter.WriteLine($"""
-                                                  #region {definitionType}s
+                                                  #region {definitionRegion}
 
                                                   """);
                 }
 
-                lastDefinitionType = definitionType;
+                lastDefinitionRegion = definitionRegion;
 
                 var methodWriter = new DefinitionWriter(this, definition);
                 methodWriter.WriteDefinition();
                 IndentedTextWriter.WriteLine();
             }
 
-            if (lastDefinitionType != "")
+            if (lastDefinitionRegion != "")
             {
                 IndentedTextWriter.WriteLine($"""
-                                              #endregion {lastDefinitionType}s
+                                              #endregion {lastDefinitionRegion}
 
                                               """);
             }

Cql/CoreTests/CSharp/ConceptDefTest-1.0.0.g.cs

@@ -81,7 +81,7 @@ private ConceptDefTest_1_0_0() {}
 
     #endregion Concepts
 
-    #region Expressions
+    #region Functions and Expressions
 
     [CqlExpressionDefinition("Patient")]
     public Patient Patient(CqlContext context)
@@ -93,6 +93,6 @@ public Patient Patient(CqlContext context)
     }
 
 
-    #endregion Expressions
+    #endregion Functions and Expressions
 
 }

Cql/CoreTests/CSharp/CqlBooleanTest-1.0.000.g.cs

@@ -28,7 +28,7 @@ private CqlBooleanTest_1_0_000() {}
 
     #endregion ILibrary Implementation
 
-    #region Expressions
+    #region Functions and Expressions
 
     [CqlExpressionDefinition("SomethingTrueEqualsTrue")]
     public bool? SomethingTrueEqualsTrue(CqlContext context)
@@ -40,6 +40,6 @@ private CqlBooleanTest_1_0_000() {}
     }
 
 
-    #endregion Expressions
+    #endregion Functions and Expressions
 
 }

Cql/CoreTests/CSharp/CqlNestedTupleTest-1.0.0.g.cs

@@ -28,7 +28,7 @@ private CqlNestedTupleTest_1_0_0() {}
 
     #endregion ILibrary Implementation
 
-    #region Expressions
+    #region Functions and Expressions
 
     [CqlExpressionDefinition("Result")]
     public (CqlTupleMetadata, string status, (CqlTupleMetadata, string result1, string result2)? result)? Result(CqlContext context)
@@ -40,7 +40,7 @@ private CqlNestedTupleTest_1_0_0() {}
     }
 
 
-    #endregion Expressions
+    #endregion Functions and Expressions
 
     #region CqlTupleMetadata Properties