add a CanPoke() extension method for memory domains, checks for a null or not implemented Poke Poke delegate, use it to disable Poke on Ram Search and Ram Watch, still todo - hex editor and lua

BizHawk.Client.EmuHawk/tools/Watch/RamSearch.cs

@@ -1173,10 +1173,13 @@ namespace BizHawk.Client.EmuHawk
 
 			RemoveMenuItem.Enabled =
 				AddToRamWatchMenuItem.Enabled =
-				PokeAddressMenuItem.Enabled =
 				FreezeAddressMenuItem.Enabled =
 				SelectedIndices.Any();
 
+			PokeAddressMenuItem.Enabled =
+				SelectedIndices.Any() &&
+				SelectedWatches.All(w => w.Domain.CanPoke());
+
 			UndoMenuItem.Enabled =
 				ClearUndoMenuItem.Enabled =
 				_searches.CanUndo;
@@ -1379,13 +1382,15 @@ namespace BizHawk.Client.EmuHawk
 
 			RemoveContextMenuItem.Visible =
 				AddToRamWatchContextMenuItem.Visible =
-				PokeContextMenuItem.Visible =
 				FreezeContextMenuItem.Visible =
 				ContextMenuSeparator2.Visible =
-
 				ViewInHexEditorContextMenuItem.Visible =
 				SelectedIndices.Any();
 
+			PokeContextMenuItem.Enabled =
+				SelectedIndices.Any() &&
+				SelectedWatches.All(w => w.Domain.CanPoke());
+
 			UnfreezeAllContextMenuItem.Visible = Global.CheatList.ActiveCount > 0;
 
 			ContextMenuSeparator3.Visible = SelectedIndices.Any() || (Global.CheatList.ActiveCount > 0);

BizHawk.Client.EmuHawk/tools/Watch/RamWatch.cs

@@ -687,10 +687,13 @@ namespace BizHawk.Client.EmuHawk
 				RemoveWatchMenuItem.Enabled =
 				MoveUpMenuItem.Enabled =
 				MoveDownMenuItem.Enabled =
-				PokeAddressMenuItem.Enabled =
 				FreezeAddressMenuItem.Enabled =
 				SelectedIndices.Any();
 
+			PokeAddressMenuItem.Enabled =
+				SelectedIndices.Any() &&
+				SelectedWatches.All(w => w.Domain.CanPoke());
+
 			PauseMenuItem.Text = _paused ? "Unpause" : "Pause";
 		}
 
@@ -1008,6 +1011,10 @@ namespace BizHawk.Client.EmuHawk
 				Separator6.Visible = 
 				indexes.Count > 0;
 
+			PokeContextMenuItem.Enabled =
+				SelectedIndices.Any() &&
+				SelectedWatches.All(w => w.Domain.CanPoke());
+
 			var allCheats = _watches.All(x => Global.CheatList.IsActive(x.Domain, x.Address ?? 0));
 
 			if (allCheats)

BizHawk.Emulation.Common/Base Implementations/MemoryDomain.cs

@@ -52,7 +52,13 @@ namespace BizHawk.Emulation.Common
 				delegate(long addr, byte val)
 				{
 					if (writable)
+					{
 						data[addr] = val;
+					}
+					else
+					{
+						throw new NotImplementedException();
+					}
 				}
 			);
 		}

BizHawk.Emulation.Common/Extensions.cs

@@ -163,6 +163,27 @@ namespace BizHawk.Emulation.Common.IEmulatorExtensions
 			return (IDisassemblable)core.ServiceProvider.GetService<IDisassemblable>();
 		}
 
+		public static bool CanPoke(this MemoryDomain d)
+		{
+			if (d.PokeByte == null)
+			{
+				return false;
+			}
+			
+			try
+			{
+				d.PokeByte(0, d.PeekByte(0));
+			}
+			catch (NotImplementedException)
+			{
+				return false;
+			}
+
+			return true;
+
+
+		}
+
 		// TODO: a better place for these
 		public static bool IsImplemented(this MethodInfo info)
 		{

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/FDS/FDS.cs

@@ -228,7 +228,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		public MemoryDomain GetDiskPeeker()
 		{
-			return new MemoryDomain("FDS SIDE", diskdrive.NumBytes, MemoryDomain.Endian.Little, diskdrive.PeekData, null); // silent poke fail TODO: don't pass null! Throw a not implemented exception, handle this exception in ram tools
+			return new MemoryDomain("FDS SIDE", diskdrive.NumBytes, MemoryDomain.Endian.Little, diskdrive.PeekData, null);
 		}
 
 		void SetIRQ()