Refactoring Keyword mapping, introducing tuples

Src/Data/Myc.Data.Keyword.pas

@@ -6,7 +6,8 @@ uses
     System.SysUtils,
     System.Generics.Collections,
     System.Generics.Defaults,
-    System.SyncObjs;
+    System.SyncObjs,
+    Myc.Data.Tuple;
 
 type
     // The runtime representation of an interned keyword
@@ -49,17 +50,18 @@ type
     // Defines a mapping from Keywords to a generic value T
     IKeywordMapping<T> = interface
         {$region 'private'}
-        function GetItems(Idx: Integer): TPair<IKeyword, T>;
+        function GetItems(Idx: Integer): T;
         function GetFields(const Key: IKeyword): T;
         function GetCount: Integer;
+        function GetKeywords(Idx: Integer): IKeyword;
         {$endregion}
         // Finds the 0-based index for a given keyword. Returns -1 if not found.
         function IndexOf(const Key: IKeyword): Integer;
 
-        // Access value by Keyword (raises exception if not found)
+        property Keywords[Idx: Integer]: IKeyword read GetKeywords;
         property Fields[const Key: IKeyword]: T read GetFields;
-        // Access Key-Value pair by Index (0..Count-1)
-        property Items[Idx: Integer]: TPair<IKeyword, T> read GetItems; default;
+        property Items[Idx: Integer]: T read GetItems; default;
+
         property Count: Integer read GetCount;
     end;
 
@@ -74,8 +76,9 @@ type
                 FFields: TArray<TPair<IKeyword, T>>;
                 FFirst, FLast: Integer;
 
-                function GetItems(Idx: Integer): TPair<IKeyword, T>;
+                function GetItems(Idx: Integer): T;
                 function GetFields(const Key: IKeyword): T;
+                function GetKeywords(Idx: Integer): IKeyword;
                 function GetCount: Integer;
             public
                 // Expects AFields to be in the desired (canonical) order
@@ -100,7 +103,8 @@ type
         FFields: TArray<TPair<IKeyword, T>>;
 
         // IKeywordMapping implementation
-        function GetItems(Idx: Integer): TPair<IKeyword, T>;
+        function GetItems(Idx: Integer): T;
+        function GetKeywords(Idx: Integer): IKeyword;
         function GetFields(const Key: IKeyword): T;
         function GetCount: Integer;
     public
@@ -224,9 +228,9 @@ begin
 end;
 
 // Interface method for Items property
-function TKeywordMappingRegistry<T>.TKeywordMapping.GetItems(Idx: Integer): TPair<IKeyword, T>;
+function TKeywordMappingRegistry<T>.TKeywordMapping.GetItems(Idx: Integer): T;
 begin
-    Result := FFields[Idx];
+    Result := FFields[Idx].Value;
 end;
 
 // Interface method for Fields property
@@ -240,6 +244,11 @@ begin
     Result := FFields[idx].Value;
 end;
 
+function TKeywordMappingRegistry<T>.TKeywordMapping.GetKeywords(Idx: Integer): IKeyword;
+begin
+    Result := FFields[Idx].Key;
+end;
+
 function TKeywordMappingRegistry<T>.TKeywordMapping.IndexOf(const Key: IKeyword): Integer;
 var
     keyIdx, mapIdx: Integer;
@@ -312,9 +321,14 @@ begin
     Result := FFields[idx].Value;
 end;
 
-function TKeywordMapping<T>.GetItems(Idx: Integer): TPair<IKeyword, T>;
+function TKeywordMapping<T>.GetItems(Idx: Integer): T;
 begin
-    Result := FFields[Idx];
+    Result := FFields[Idx].Value;
+end;
+
+function TKeywordMapping<T>.GetKeywords(Idx: Integer): IKeyword;
+begin
+    Result := FFields[Idx].Key;
 end;
 
 function TKeywordMapping<T>.IndexOf(const Key: IKeyword): Integer;