Change return type of `IEmulationApi.Disassemble` to tuple

src/BizHawk.Client.Common/Api/Classes/EmulationApi.cs

@@ -73,25 +73,23 @@ namespace BizHawk.Client.Common
 		public int FrameCount()
 			=> Emulator!.Frame;
 
-		public object? Disassemble(uint pc, string? name = null)
+		public (string Disasm, int Length) Disassemble(uint pc, string? name = null)
 		{
 			try
 			{
 				if (DisassemblableCore != null)
 				{
-					return new {
-						disasm = DisassemblableCore.Disassemble(
-							string.IsNullOrEmpty(name) ? MemoryDomains!.SystemBus : MemoryDomains![name!]!,
-							pc,
-							out var l
-						),
-						length = l
-					};
+					var disasm = DisassemblableCore.Disassemble(
+						string.IsNullOrEmpty(name) ? MemoryDomains!.SystemBus : MemoryDomains![name!]!,
+						pc,
+						out var l
+					);
+					return (disasm, l);
 				}
 			}
 			catch (NotImplementedException) {}
 			LogCallback($"Error: {Emulator.Attributes().CoreName} does not yet implement {nameof(IDisassemblable.Disassemble)}()");
-			return null;
+			return (string.Empty, 0);
 		}
 
 		public ulong? GetRegister(string name)

src/BizHawk.Client.Common/Api/Interfaces/IEmulationApi.cs

@@ -10,7 +10,10 @@ namespace BizHawk.Client.Common
 	{
 		void DisplayVsync(bool enabled);
 		int FrameCount();
-		object? Disassemble(uint pc, string? name = null);
+
+		/// <returns>disassembly and opcode width, or <c>(string.Empty, 0)</c> on failure</returns>
+		(string Disasm, int Length) Disassemble(uint pc, string? name = null);
+
 		ulong? GetRegister(string name);
 		IReadOnlyDictionary<string, ulong> GetRegisters();
 		void SetRegister(string register, int value);

src/BizHawk.Client.Common/lua/CommonLibs/EmulationLuaLibrary.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.ComponentModel;
 
 using NLua;
@@ -38,8 +39,15 @@ namespace BizHawk.Client.Common
 		[LuaMethodExample("local obemudis = emu.disassemble( 0x8000 );")]
 		[LuaMethod("disassemble", "Returns the disassembly object (disasm string and length int) for the given PC address. Uses System Bus domain if no domain name provided")]
 		[return: LuaASCIIStringParam]
-		public object Disassemble(uint pc, [LuaASCIIStringParam] string name = "")
-			=> APIs.Emulation.Disassemble(pc, name);
+		public LuaTable Disassemble(uint pc, [LuaASCIIStringParam] string name = "")
+		{
+			var (disasm, length) = APIs.Emulation.Disassemble(pc, name);
+			if (length is 0) return null;
+			var table = _th.CreateTable();
+			table["disasm"] = disasm;
+			table["length"] = length;
+			return table;
+		}
 
 		// TODO: what about 64 bit registers?
 		[LuaMethodExample("local inemuget = emu.getregister( emu.getregisters( )[ 0 ] );")]