Implemented TLazy + Tests

Src/Myc.Core.Futures.pas

@@ -7,15 +7,19 @@ uses
     Myc.Signals, Myc.TaskManager, Myc.Futures;
 
 type
-    // Abstract base class for IMycFuture<T> implementations.
     TMycFuture<T> = class abstract( TInterfacedObject, IMycFuture<T> )
     protected
         function GetResult: T; virtual; abstract;
         function GetDone: IMycState; virtual; abstract;
     end;
 
-    // Concrete future implementation triggered by an initial state, executing a TFunc<T>.
-    TMycInitStateFuncFuture<T> = class( TMycFuture<T> )
+    TMycNullFuture<T> = class( TMycFuture<T> )
+    protected
+        function GetResult: T; override;
+        function GetDone: IMycState; override;
+    end;
+
+    TMycGateFuncFuture<T> = class(TMycFuture<T>)
     private
         FInit: TMycSubscription;
         FDone: IMycLatch;
@@ -24,20 +28,31 @@ type
         function GetResult: T; override;
         function GetDone: IMycState; override;
     public
-        // Creates a future that executes AProc after AGate is set, using ATaskFactory.
         constructor Create( const ATaskManager: IMycTaskManager; const AGate: IMycState; AProc: TFunc<T> );
         destructor Destroy; override;
     end;
 
 implementation
 
-{ TMycInitStateFuncFuture<T> }
+{ TMycNullFuture<T> }
 
-constructor TMycInitStateFuncFuture<T>.Create( const ATaskManager: IMycTaskManager; const AGate: IMycState; AProc: TFunc<T> );
+function TMycNullFuture<T>.GetDone: IMycState;
+begin
+    Result := TState.Null;
+end;
+
+function TMycNullFuture<T>.GetResult: T;
+begin
+    Result := Default(T);
+end;
+
+{ TMycGateFuncFuture<T> }
+
+constructor TMycGateFuncFuture<T>.Create(const ATaskManager: IMycTaskManager; const AGate: IMycState; AProc: TFunc<T>);
 begin
     inherited Create;
 
-    FDone := TState.CreateLatch( 1 );
+    FDone := TLatch.Construct( 1 );
 
     // Subscribe the job execution to AGate.
     // The job will run when AGate notifies the subscriber returned by Run.
@@ -58,7 +73,7 @@ begin
         end );
 end;
 
-destructor TMycInitStateFuncFuture<T>.Destroy;
+destructor TMycGateFuncFuture<T>.Destroy;
 begin
     Assert( FDone.State.IsSet );
 
@@ -66,12 +81,12 @@ begin
     inherited Destroy;
 end;
 
-function TMycInitStateFuncFuture<T>.GetDone: IMycState;
+function TMycGateFuncFuture<T>.GetDone: IMycState;
 begin
     Result := FDone.State;
 end;
 
-function TMycInitStateFuncFuture<T>.GetResult: T;
+function TMycGateFuncFuture<T>.GetResult: T;
 begin
     Assert( FDone.State.IsSet, 'Result is not yet available.' );
     Result := FResult;