diff --git a/mpw/mpw.cpp b/mpw/mpw.cpp
index a6f3a23..dc265fb 100644
--- a/mpw/mpw.cpp
+++ b/mpw/mpw.cpp
@@ -263,8 +263,6 @@ namespace MPW
 		uint32_t devptr = 0;
 		uint32_t fptr = 0;
 
-		uint16_t error;
-
 		// create the argv-data.
 		{
 			uint32_t size = 0;
@@ -278,8 +276,9 @@ namespace MPW
 				size += l;
 			}
 
-			error = MM::Native::NewPtr(size, true, argvptr);
-			if (error) return error;
+			auto tmp = MM::Native::NewPtr(size, true);
+			if (tmp.error()) return tmp.error();
+			argvptr = tmp.value();
 
 
 			uint8_t *xptr = memoryPointer(argvptr);
@@ -331,9 +330,9 @@ namespace MPW
 
 			size += 4; // space for null terminator.
 
-			error = MM::Native::NewPtr(size, true, envptr);
-			if (error) return error;
-
+			auto tmp = MM::Native::NewPtr(size, true);
+			if (tmp.error()) return tmp.error();
+			envptr = tmp.value();
 
 			uint8_t *xptr = memoryPointer(envptr);
 			uint32_t offset = 0;
@@ -364,9 +363,9 @@ namespace MPW
 			// these are ftraps for emulated/native function ptrs.
 			uint32_t size = 6 * 4;
 
-			error = MM::Native::NewPtr(size, true, fptr);
-
-			if (error) return error;
+			auto tmp = MM::Native::NewPtr(size, true);
+			if (tmp.error()) return tmp.error();
+			fptr = tmp.value();
 
 			memoryWriteWord(fQuit, fptr + 0);
 			memoryWriteWord(0x4E75, fptr + 2); // rts
@@ -393,9 +392,9 @@ namespace MPW
 		{
 			uint32_t size = 0x78;
 
-			error = MM::Native::NewPtr(size, true, devptr);
-
-			if (error) return error;
+			auto tmp = MM::Native::NewPtr(size, true);
+			if (tmp.error()) return tmp.error();
+			devptr = tmp.value();
 
 			memoryWriteLong(0x46535953, devptr + 0); // 'FSYS'
 			memoryWriteLong(fptr + 4, devptr + 4);
@@ -415,9 +414,9 @@ namespace MPW
 			uint32_t size = 0x3c;
 			uint32_t ptr;
 
-			error = MM::Native::NewPtr(size, true, ioptr);
-
-			if (error) return error;
+			auto tmp = MM::Native::NewPtr(size, true);
+			if (tmp.error()) return tmp.error();
+			ioptr = tmp.value();
 
 			ptr = ioptr;
 			// stdin
@@ -450,10 +449,9 @@ namespace MPW
 
 
 
-		uint32_t mpi = 0;
-
-		error = MM::Native::NewPtr(8 + 0x30, true, mpi);
-		if (error) return error;
+		auto tmp = MM::Native::NewPtr(8 + 0x30, true);
+		if (tmp.error()) return tmp.error();
+		uint32_t mpi = tmp.value();
 
 		MacProgramInfo = mpi + 8;
 
diff --git a/toolbox/dispatch.cpp b/toolbox/dispatch.cpp
index e2a2901..c522618 100644
--- a/toolbox/dispatch.cpp
+++ b/toolbox/dispatch.cpp
@@ -350,7 +350,8 @@ namespace ToolBox {
 
 
 		// alternate entry code
-		MM::Native::NewPtr(1024 * 4 + 256 * 4, false, ToolGlue);
+		auto tmp = MM::Native::NewPtr(1024 * 4 + 256 * 4, false);
+		ToolGlue = tmp.value();
 		OSGlue = ToolGlue + 1024 * 4;
 
 		uint16_t *code = (uint16_t *)memoryPointer(ToolGlue);
diff --git a/toolbox/loader.cpp b/toolbox/loader.cpp
index 32330f1..7f66d35 100644
--- a/toolbox/loader.cpp
+++ b/toolbox/loader.cpp
@@ -148,21 +148,24 @@ namespace Loader {
 		// load code seg 0.
 		uint16_t LoadCode0(Segment0Info &rv)
 		{
-			uint16_t err;
 			uint32_t rHandle;
 			uint32_t size;
 			uint32_t address;
 
 			SegmentInfo si;
 
-			err = RM::Native::GetResource(kCODE, 0, rHandle);
-			if (err) return err;
-
+			{
+				auto tmp = RM::Native::GetResource(kCODE, 0);
+				if (tmp.error()) return tmp.error();
+				rHandle = tmp.value();
+			}
 
 			MM::Native::HLock(rHandle);
-			MM::Native::GetHandleSize(rHandle, size);
-
-			address = memoryReadLong(rHandle);
+			{
+				auto tmp = MM::Native::GetHandleInfo(rHandle);
+				address = tmp.value().address;
+				size = tmp.value().size;
+			}
 
 			uint32_t above = memoryReadLong(address);
 			uint32_t below = memoryReadLong(address + 4);
@@ -173,8 +176,12 @@ namespace Loader {
 
 
 			// create a new handle for the a5 segment.
-			err = MM::Native::NewHandle(si.size, true, si.handle, si.address);
-			if (err) return err;
+			{
+				auto tmp = MM::Native::NewHandle(si.size, true);
+				if (tmp.error()) return tmp.error();
+				si.handle = tmp.value().handle;
+				si.address = tmp.value().pointer;
+			}
 
 			MM::Native::HLock(si.handle);
 
@@ -198,17 +205,21 @@ namespace Loader {
 		// load a standard code segment.
 		uint16_t LoadCode(uint16_t segment)
 		{
-			uint16_t err;
 
 			SegmentInfo si;
 
-			err = RM::Native::GetResource(kCODE, segment, si.handle);
-			if (err) return err;
-
+			{
+				auto tmp = RM::Native::GetResource(kCODE, segment);
+				if (tmp.error()) return tmp.error();
+				si.handle = tmp.value();
+			}
 			MM::Native::HLock(si.handle);
-			MM::Native::GetHandleSize(si.handle, si.size);
 
-			si.address = memoryReadLong(si.handle);
+			{
+				auto tmp = MM::Native::GetHandleInfo(si.handle);
+				si.size = tmp.value().size;
+				si.address = tmp.value().address;
+			}
 
 			if (memoryReadWord(si.address) == 0xffff)
 				si.farModel = true;
@@ -343,7 +354,7 @@ namespace Loader {
 			{
 				std::string s;
 
-				auto ix = path.rfind('/');
+				auto ix = path.find_last_of("/:", 0, 2);
 				if (ix == path.npos)
 				{
 					s = path.substr(0, 31);
@@ -552,5 +563,35 @@ namespace Loader {
 	}
 
 
+	uint16_t LoadSeg(uint16_t trap) {
+
+
+		/*
+		 * Jump Table Entry:
+		 *
+		 * Unloaded:
+		 * +0 offset
+		 * +2 instruction that pushes segment number onto stack
+		 * +6 LoadSeg trap
+		 *
+		 * Loaded:
+		 * +0 offset
+		 * +2 jump instruction.
+		 *
+		 */
+
+
+
+		uint32_t sp;
+		uint16_t segment;
+
+		sp = StackFrame<2>(segment);
+
+		Log("%04x LoadSeg(%04x)\n", trap, segment);
+
+		return 0;
+
+	}
+
 
 }
diff --git a/toolbox/loader.h b/toolbox/loader.h
index 5793ea2..0b6b63e 100644
--- a/toolbox/loader.h
+++ b/toolbox/loader.h
@@ -26,6 +26,7 @@ namespace Loader {
 
 	}
 
+	uint16_t LoadSeg(uint16_t trap);
 	uint16_t UnloadSeg(uint16_t trap);
 
 }
diff --git a/toolbox/mm.cpp b/toolbox/mm.cpp
index 7f8daa9..2d165d2 100644
--- a/toolbox/mm.cpp
+++ b/toolbox/mm.cpp
@@ -45,6 +45,9 @@
 
 using ToolBox::Log;
 
+using MacOS::tool_return;
+using MacOS::macos_error_from_errno;
+using MacOS::macos_error;
 
 namespace
 {
@@ -65,15 +68,15 @@ namespace
 	// map of handle -> size [? just use Ptr map?]
 	std::map<uint32_t, MM::HandleInfo> HandleMap;
 
-	inline MacOS::macos_error SetMemError(MacOS::macos_error error)
+	inline macos_error SetMemError(macos_error error)
 	{
 		memoryWriteWord(error, MacOS::MemErr);
 		return error;
 	}
 
-	inline MacOS::macos_error SetMemError(int16_t error)
+	inline macos_error SetMemError(int16_t error)
 	{
-		return SetMemError((MacOS::macos_error)error);
+		return SetMemError((macos_error)error);
 	}
 
 
@@ -98,13 +101,6 @@ namespace
 	}
 
 
-	template<class Fx>
-	int16_t with_handle(uint32_t handle, Fx fx)
-	{
-		auto iter = HandleMap.find(handle);
-		if (iter == HandleMap.end()) return MacOS::memWZErr;
-		return fx(iter->second);
-	}
 }
 
 namespace MM
@@ -139,6 +135,46 @@ namespace MM
 	namespace Native {
 
 
+		template<class T>
+		struct tool_return_base { typedef T type; };
+
+		template<class T>
+		struct tool_return_base<tool_return<T>> { typedef T type; };
+
+
+		template<class T, class F>
+		tool_return<T> with_handle_helper(F &&f, HandleInfo &info, typename std::enable_if<!std::is_void<T>::value>::type* = 0) {
+			tool_return<T> rv = f(info);
+			return rv;
+		}
+
+		template<class T, class F>
+		tool_return<void> with_handle_helper(F &&f, HandleInfo &info, typename std::enable_if<std::is_void<T>::value>::type* = 0) {
+			f(info);
+			return tool_return<void>();
+		}
+
+
+
+		template<class F, typename T = typename tool_return_base<typename std::result_of<F(HandleInfo &)>::type>::type>
+		tool_return<T>
+		__with_handle(uint32_t handle, F &&f)
+		{
+			const auto iter = HandleMap.find(handle);
+
+			if (iter == HandleMap.end()) {
+				tool_return<T> rv = SetMemError(MacOS::memWZErr);
+				return rv;
+			}
+
+			auto &info = iter->second;
+			//tool_return<T> rv = f(info);
+			tool_return<T> rv = with_handle_helper<T>(std::forward<F>(f), info);
+			SetMemError(rv.error());
+			return rv;	
+		}
+
+
 		// debugger support.
 		// print info on an address.
 		void MemoryInfo(uint32_t address)
@@ -233,11 +269,11 @@ namespace MM
 		}
 
 
-		uint16_t NewPtr(uint32_t size, bool clear, uint32_t &mcptr)
+		tool_return<uint32_t> NewPtr(uint32_t size, bool clear)
 		{
 			// native pointers.
 
-			mcptr = 0;
+			uint32_t mcptr = 0;
 			//if (size == 0) return 0;
 
 			uint8_t *ptr = nullptr;
@@ -253,10 +289,11 @@ namespace MM
 			mcptr = ptr - Memory;
 			PtrMap.emplace(std::make_pair(mcptr, size));
 
-			return SetMemError(0);
+			SetMemError(0);
+			return mcptr;
 		}
 
-		uint16_t DisposePtr(uint32_t mcptr)
+		tool_return<void> DisposePtr(uint32_t mcptr)
 		{
 
 			auto iter = PtrMap.find(mcptr);
@@ -271,13 +308,13 @@ namespace MM
 			return SetMemError(0);
 		}
 
-		uint16_t NewHandle(uint32_t size, bool clear, uint32_t &handle, uint32_t &mcptr)
+		tool_return<hp> NewHandle(uint32_t size, bool clear)
 		{
 			uint8_t *ptr;
 			uint32_t hh;
 
-			handle = 0;
-			mcptr = 0;
+			uint32_t handle = 0;
+			uint32_t mcptr = 0;
 
 			if (!HandleQueue.size())
 			{
@@ -316,18 +353,12 @@ namespace MM
 
 			memoryWriteLong(mcptr, hh);
 			handle = hh;
-			return SetMemError(0);
-		}
-
-		uint16_t NewHandle(uint32_t size, bool clear, uint32_t &handle)
-		{
-			uint32_t ptr;
-			return NewHandle(size, clear, handle, ptr);
+			SetMemError(0);
+			return hp{handle, mcptr};
 		}
 
 
-
-		uint16_t DisposeHandle(uint32_t handle)
+		tool_return<void> DisposeHandle(uint32_t handle)
 		{
 			auto iter = HandleMap.find(handle);
 
@@ -349,19 +380,9 @@ namespace MM
 		}
 
 
-		uint16_t GetHandleSize(uint32_t handle, uint32_t &handleSize)
-		{
-			handleSize = 0;
-
-			const auto iter = HandleMap.find(handle);
-
-			if (iter == HandleMap.end()) return SetMemError(MacOS::memWZErr);
-			handleSize = iter->second.size;
-			return SetMemError(0);
-		}
 
 
-		uint16_t ReallocHandle(uint32_t handle, uint32_t logicalSize)
+		tool_return<void> ReallocHandle(uint32_t handle, uint32_t logicalSize)
 		{
 
 			auto iter = HandleMap.find(handle);
@@ -400,12 +421,12 @@ namespace MM
 
 			// lock?  clear purged flag?
 
-			return 0;
+			return MacOS::noErr;
 
 		}
 
 
-		uint16_t SetHandleSize(uint32_t handle, uint32_t newSize)
+		tool_return<void> SetHandleSize(uint32_t handle, uint32_t newSize)
 		{
 			if (handle == 0) return SetMemError(MacOS::nilHandleErr);
 
@@ -519,61 +540,35 @@ namespace MM
 
 		}
 
-		// template class to validate handle and work on it.
-		template<class FX>
-		uint16_t HandleIt(uint32_t handle, FX fx)
+
+		tool_return<void> HSetRBit(uint32_t handle)
 		{
-			const auto iter = HandleMap.find(handle);
-
-			if (iter == HandleMap.end()) return SetMemError(MacOS::memWZErr);
-
-			auto &info = iter->second;
-			fx(info);
-			return SetMemError(0);
+			return __with_handle(handle, [](HandleInfo &info) { info.resource = true; });
 		}
 
-		uint16_t HSetRBit(uint32_t handle)
+		tool_return<void> HClrRBit(uint32_t handle)
 		{
-			const auto iter = HandleMap.find(handle);
-
-			if (iter == HandleMap.end()) return SetMemError(MacOS::memWZErr);
-
-			auto &info = iter->second;
-			info.resource = true;
-			return SetMemError(0);
+			return __with_handle(handle, [](HandleInfo &info) { info.resource = false; });
 		}
 
-		uint16_t HClrRBit(uint32_t handle)
+		tool_return<void> HLock(uint32_t handle)
 		{
-			const auto iter = HandleMap.find(handle);
-
-			if (iter == HandleMap.end()) return SetMemError(MacOS::memWZErr);
-
-			auto &info = iter->second;
-			info.resource = false;
-			return SetMemError(0);
+			return __with_handle(handle, [](HandleInfo &info) { info.locked = true; });
 		}
 
-		uint16_t HLock(uint32_t handle)
+		tool_return<void> HUnlock(uint32_t handle)
 		{
-			const auto iter = HandleMap.find(handle);
-
-			if (iter == HandleMap.end()) return SetMemError(MacOS::memWZErr);
-
-			auto &info = iter->second;
-			info.locked = true;
-			return SetMemError(0);
+			return __with_handle(handle, [](HandleInfo &info) { info.locked = false; });
 		}
 
-		uint16_t HUnlock(uint32_t handle)
+		tool_return<uint32_t> GetHandleSize(uint32_t handle)
 		{
-			const auto iter = HandleMap.find(handle);
+			return __with_handle(handle, [](const HandleInfo &info){ return info.size; });
+		}
 
-			if (iter == HandleMap.end()) return SetMemError(MacOS::memWZErr);
-
-			auto &info = iter->second;
-			info.locked = false;
-			return SetMemError(0);
+		tool_return<HandleInfo> GetHandleInfo(uint32_t handle)
+		{
+			return __with_handle(handle, [](const HandleInfo &info){ return info; });
 		}
 
 
@@ -583,25 +578,7 @@ namespace MM
 
 	#pragma mark --
 
-	tool_return<uint32_t> GetHandleSize(uint32_t handle)
-	{
 
-		const auto iter = HandleMap.find(handle);
-
-		if (iter == HandleMap.end()) return SetMemError(MacOS::memWZErr);
-
-		SetMemError(0);
-		return iter->second.size;
-	}
-
-	tool_return<HandleInfo> GetHandleInfo(uint32_t handle)
-	{
-		const auto iter = HandleMap.find(handle);
-
-		if (iter == HandleMap.end()) return SetMemError(MacOS::memWZErr);
-		SetMemError(0);
-		return iter->second;
-	}
 
 
 	#pragma mark --
@@ -828,12 +805,10 @@ namespace MM
 		// todo -- separate pools for sys vs non-sys?
 		// todo -- NewPtr(0) -- null or empty ptr?
 
-		uint32_t mcptr;
-		uint16_t error;
-		error = Native::NewPtr(size, clear, mcptr);
+		auto rv = Native::NewPtr(size, clear);
 
-		cpuSetAReg(0, mcptr);
-		return error; //SetMemError(error);
+		cpuSetAReg(0, rv.value());
+		return rv.error(); //SetMemError(error);
 	}
 
 	uint16_t DisposePtr(uint16_t trap)
@@ -852,10 +827,9 @@ namespace MM
 		Log("%04x DisposePtr(%08x)\n", trap, mcptr);
 
 
-		uint16_t error;
-		error = Native::DisposePtr(mcptr);
+		auto rv = Native::DisposePtr(mcptr);
 
-		return error; //SetMemError(error);
+		return rv.error(); //SetMemError(error);
 	}
 
 	uint32_t GetPtrSize(uint16_t trap)
@@ -928,8 +902,6 @@ namespace MM
 		 *
 		 */
 
-		uint32_t hh = 0;
-		uint16_t error;
 
 		bool clear = trap & (1 << 9);
 		//bool sys = trap & (1 << 10);
@@ -938,10 +910,10 @@ namespace MM
 
 		Log("%04x NewHandle(%08x)\n", trap, size);
 
-		error = Native::NewHandle(size, clear, hh);
+		auto rv = Native::NewHandle(size, clear);
 
-		cpuSetAReg(0, hh);
-		return error;
+		cpuSetAReg(0, rv.value().handle);
+		return rv.error();
 	}
 
 	uint16_t DisposeHandle(uint16_t trap)
@@ -959,7 +931,7 @@ namespace MM
 
 		Log("%04x DisposeHandle(%08x)\n", trap, hh);
 
-		return Native::DisposeHandle(hh);
+		return Native::DisposeHandle(hh).error();
 	}
 
 	uint16_t EmptyHandle(uint16_t trap)
@@ -1026,7 +998,7 @@ namespace MM
 
 		Log("%04x ReallocHandle(%08x, %08x)\n", trap, hh, logicalSize);
 
-		return Native::ReallocHandle(hh, logicalSize);
+		return Native::ReallocHandle(hh, logicalSize).error();
 
 #if 0
 		auto iter = HandleMap.find(hh);
@@ -1121,7 +1093,7 @@ namespace MM
 
 		Log("%04x SetHandleSize(%08x, %08x)\n", trap, hh, newSize);
 
-		return Native::SetHandleSize(hh, newSize);
+		return Native::SetHandleSize(hh, newSize).error();
 	}
 
 	uint32_t RecoverHandle(uint16_t trap)
@@ -1368,16 +1340,15 @@ namespace MM
 		auto const info = iter->second;
 
 
-		uint32_t destHandle;
-		uint32_t destPtr;
-		uint32_t d0 = Native::NewHandle(info.size, false, destHandle, destPtr);
-		if (d0 == 0)
+		auto rv = Native::NewHandle(info.size, false);
+
+		if (!rv.error())
 		{
-			std::memmove(memoryPointer(destPtr), memoryPointer(info.address), info.size);
+			std::memmove(memoryPointer(rv.value().pointer), memoryPointer(info.address), info.size);
 		}
 
-		cpuSetAReg(0, destHandle);
-		return d0; // SetMemError called by Native::NewHandle.
+		cpuSetAReg(0, rv.value().handle);
+		return rv.error(); // SetMemError called by Native::NewHandle.
 	}
 
 
@@ -1399,16 +1370,14 @@ namespace MM
 
 		Log("%04x PtrToHand(%08x, %08x)\n", trap, mcptr, size);
 
-		uint32_t destHandle;
-		uint32_t destPtr;
-		uint32_t d0 = Native::NewHandle(size, false, destHandle, destPtr);
-		if (d0 == 0)
+		auto rv = Native::NewHandle(size, false);
+		if (!rv.error())
 		{
-			std::memmove(memoryPointer(destPtr), memoryPointer(mcptr), size);
+			std::memmove(memoryPointer(rv.value().pointer), memoryPointer(mcptr), size);
 		}
 
-		cpuSetAReg(0, destHandle);
-		return d0; // SetMemError called by Native::NewHandle.
+		cpuSetAReg(0, rv.value().handle);
+		return rv.error(); // SetMemError called by Native::NewHandle.
 	}
 
 	uint16_t PtrAndHand(uint16_t trap)
@@ -1435,18 +1404,16 @@ namespace MM
 
 		cpuSetAReg(0, handle);
 
-		uint32_t oldSize = 0;
-		uint32_t d0;
-
-		d0 = Native::GetHandleSize(handle, oldSize);
-		if (d0) return d0;
+		auto tmp = Native::GetHandleSize(handle);
+		if (tmp.error()) return tmp.error();
+		uint32_t oldSize = tmp.value();
 
 		if ((uint64_t)oldSize + (uint64_t)size > UINT32_MAX)
 			return SetMemError(MacOS::memFullErr);
 
 
-		d0 = Native::SetHandleSize(handle, oldSize + size);
-		if (d0) return d0;
+		auto err = Native::SetHandleSize(handle, oldSize + size);
+		if (err.error()) return err.error();
 
 		auto iter = HandleMap.find(handle);
 		if (iter == HandleMap.end())
@@ -1637,20 +1604,18 @@ namespace MM
 	{
 		// FUNCTION TempNewHandle (logicalSize: Size;
 		//                         VAR resultCode: OSErr): Handle;
-		uint16_t rv;
 		uint32_t logicalSize;
 		uint32_t resultCode;
-		uint32_t theHandle;
 
 		uint32_t sp = StackFrame<8>(logicalSize, resultCode);
 
 		Log("     TempNewHandle(%08x, %08x)\n", logicalSize, resultCode);
 
-		rv = Native::NewHandle(logicalSize, true, theHandle);
+		auto rv = Native::NewHandle(logicalSize, true);
 
-		if (resultCode) memoryWriteWord(rv, resultCode);
-		ToolReturn<4>(sp, theHandle);
-		return rv;
+		if (resultCode) memoryWriteWord(rv.error(), resultCode);
+		ToolReturn<4>(sp, rv.value().handle);
+		return rv.error();
 	}
 
 	uint16_t TempHLock(void)
@@ -1663,10 +1628,10 @@ namespace MM
 
 		Log("     TempHLock(%08x, %08x)\n", theHandle, resultCode);
 
-		uint16_t rv = Native::HLock(theHandle);
+		auto rv = Native::HLock(theHandle);
 
-		if (resultCode) memoryWriteWord(rv, resultCode);
-		return rv;
+		if (resultCode) memoryWriteWord(rv.error(), resultCode);
+		return rv.error();
 	}
 
 	uint16_t TempHUnlock(void)
@@ -1679,10 +1644,10 @@ namespace MM
 
 		Log("     TempHUnlock(%08x, %08x)\n", theHandle, resultCode);
 
-		uint16_t rv = Native::HUnlock(theHandle);
+		auto rv = Native::HUnlock(theHandle);
 
-		if (resultCode) memoryWriteWord(rv, resultCode);
-		return rv;
+		if (resultCode) memoryWriteWord(rv.error(), resultCode);
+		return rv.error();
 	}
 
 
@@ -1696,9 +1661,9 @@ namespace MM
 
 		Log("     TempDisposeHandle(%08x, %08x)\n", theHandle, resultCode);
 
-		uint16_t rv = Native::DisposeHandle(theHandle);
+		auto rv = Native::DisposeHandle(theHandle);
 
-		if (resultCode) memoryWriteWord(rv, resultCode);
-		return rv;
+		if (resultCode) memoryWriteWord(rv.error(), resultCode);
+		return rv.error();
 	}
 }
diff --git a/toolbox/mm.h b/toolbox/mm.h
index 6b8b909..e7a9399 100644
--- a/toolbox/mm.h
+++ b/toolbox/mm.h
@@ -5,37 +5,9 @@
 
 #include <macos/tool_return.h>
 
+
 namespace MM
 {
-	// native functions.
-	namespace Native
-	{
-
-		void MemoryInfo(uint32_t address);
-		void PrintMemoryStats();
-
-		uint16_t NewHandle(uint32_t size, bool clear, uint32_t &handle);
-		uint16_t NewHandle(uint32_t size, bool clear, uint32_t &handle, uint32_t &ptr);
-
-		uint16_t NewPtr(uint32_t size, bool clear, uint32_t &pointer);
-
-		uint16_t DisposeHandle(uint32_t handle);
-		uint16_t DisposePtr(uint32_t pointer);
-
-		uint16_t GetHandleSize(uint32_t handle, uint32_t &handleSize);
-
-		uint16_t SetHandleSize(uint32_t handle, uint32_t newSize);
-		uint16_t ReallocHandle(uint32_t handle, uint32_t newSize);
-
-		uint16_t HSetRBit(uint32_t handle);
-		uint16_t HClrRBit(uint32_t handle);
-
-		uint16_t HLock(uint32_t handle);
-		uint16_t HUnlock(uint32_t handle);
-	}
-
-	bool Init(uint8_t *memory, uint32_t memorySize, uint32_t globals, uint32_t stack);
-
 
 	struct HandleInfo
 	{
@@ -50,11 +22,54 @@ namespace MM
 		{}
 	};
 
+
+	// native functions.
+	namespace Native
+	{
+
+		using MacOS::tool_return;
+
+		struct hp {
+			uint32_t handle = 0;
+			uint32_t pointer = 0; 
+			hp() = default;
+			hp(uint32_t a, uint32_t b) : handle(a), pointer(b) {};
+		};
+
+		void MemoryInfo(uint32_t address);
+		void PrintMemoryStats();
+
+		tool_return<hp> NewHandle(uint32_t size, bool clear);
+
+		tool_return<uint32_t> NewPtr(uint32_t size, bool clear);
+
+		tool_return<void> DisposeHandle(uint32_t handle);
+		tool_return<void> DisposePtr(uint32_t pointer);
+
+		tool_return<uint32_t> GetHandleSize(uint32_t handle);
+
+		tool_return<void> SetHandleSize(uint32_t handle, uint32_t newSize);
+		tool_return<void> ReallocHandle(uint32_t handle, uint32_t newSize);
+
+		tool_return<void> HSetRBit(uint32_t handle);
+		tool_return<void> HClrRBit(uint32_t handle);
+
+		tool_return<void> HLock(uint32_t handle);
+		tool_return<void> HUnlock(uint32_t handle);
+
+
+		tool_return<HandleInfo> GetHandleInfo(uint32_t handle);
+
+		tool_return<uint32_t> GetHandleSize(uint32_t handle);
+	}
+
+	bool Init(uint8_t *memory, uint32_t memorySize, uint32_t globals, uint32_t stack);
+
+
+
 	using MacOS::tool_return;
 
-	tool_return<HandleInfo> GetHandleInfo(uint32_t handle);
 
-	tool_return<uint32_t> GetHandleSize(uint32_t handle);
 
 
 	uint16_t BlockMove(uint16_t trap);
diff --git a/toolbox/rm.cpp b/toolbox/rm.cpp
index e282f4d..ad96c0a 100644
--- a/toolbox/rm.cpp
+++ b/toolbox/rm.cpp
@@ -112,10 +112,10 @@ namespace
 	std::map<uint32_t, Handle> rhandle_map;
 
 
-	inline uint16_t SetResError(uint16_t error)
+	inline macos_error SetResError(uint16_t error)
 	{
 		memoryWriteWord(error, MacOS::ResErr);
-		return error;
+		return (macos_error)error;
 	}
 
 	bool LoadResType(uint32_t type)
@@ -165,10 +165,9 @@ namespace RM
 		// not to be confused with MacOS LoadResource(theHandle)
 
 		template<class FX>
-		uint16_t LoadResource(uint32_t type, uint32_t &theHandle, FX fx)
+		macos_error LoadResource(uint32_t type, uint32_t &theHandle, FX fx)
 		{
 			uint32_t ptr;
-			uint16_t error;
 
 			Handle nativeHandle;
 			uint32_t size;
@@ -190,14 +189,18 @@ namespace RM
 			if (ResLoad) ::LoadResource(nativeHandle);
 
 			size = ::GetHandleSize(nativeHandle);
-			error = MM::Native::NewHandle(size, false, theHandle, ptr);
+			{
+				auto tmp = MM::Native::NewHandle(size, false);
+				if (tmp.error()) {
+					::ReleaseResource(nativeHandle);
+					return SetResError(tmp.error());
+				}
+				theHandle = tmp.value().handle;
+				ptr = tmp.value().pointer;
+			}
 			// TODO -- need to lock if native handle locked.
 
-			if (!theHandle)
-			{
-				::ReleaseResource(nativeHandle);
-				return SetResError(error);
-			}
+
 			MM::Native::HSetRBit(theHandle);
 
 			if (size)
@@ -213,15 +216,19 @@ namespace RM
 
 		// used by GetString (utility.h)
 		// used by Loader.
-		uint16_t GetResource(uint32_t type, uint16_t id, uint32_t &theHandle)
+		tool_return<uint32_t> GetResource(uint32_t type, uint16_t id)
 		{
-			return LoadResource(type, theHandle,
+			uint32_t theHandle;
+			auto err = LoadResource(type, theHandle,
 				[type, id](){
 					return ::GetResource(type, id);
 				});
+
+			if (!err) return theHandle;
+			return err;
 		}
 
-		uint16_t SetResLoad(bool load)
+		tool_return<void> SetResLoad(bool load)
 		{
 
 			ResLoad = load;
@@ -232,6 +239,19 @@ namespace RM
 		}
 
 
+
+		tool_return<void> CloseResFile(uint16_t refNum)
+		{
+			// If the value of the refNum parameter is 0, it represents the System file and is ignored.
+
+			if (refNum != 0)
+			{
+				::CloseResFile(refNum);
+				return SetResError(::ResError());
+			}
+			return SetResError(0);
+		}
+
 	}
 
 	uint16_t CloseResFile(uint16_t trap)
@@ -844,7 +864,7 @@ namespace RM
 
 		// check if handle size changed, resync data
 
-		auto info = MM::GetHandleInfo(theResource);
+		auto info = MM::Native::GetHandleInfo(theResource);
 		if (!info.error()) return SetResError(info.error());
 
 
@@ -928,7 +948,7 @@ namespace RM
 
 		Handle nativeHandle = NULL;
 
-		auto info = MM::GetHandleInfo(theData);
+		auto info = MM::Native::GetHandleInfo(theData);
 		if (info.error()) return SetResError(MacOS::addResFailed);
 
 
@@ -1179,7 +1199,7 @@ namespace RM
 
 
 		// if it has a size, it's loaded...
-		auto info = MM::GetHandleInfo(theResource);
+		auto info = MM::Native::GetHandleInfo(theResource);
 		if (info.error()) return SetResError(resNotFound);
 		if (info->size) return SetResError(0);
 
@@ -1198,14 +1218,14 @@ namespace RM
 
 		size = ::GetHandleSize(nativeHandle);
 
-		err = MM::Native::ReallocHandle(theResource, size);
-		if (err) return SetResError(err);
+		auto tmp = MM::Native::ReallocHandle(theResource, size);
+		if (tmp.error()) return SetResError(tmp.error());
 
 		// todo -- need to lock if resource locked.
 
 		if (size)
 		{
-			info = MM::GetHandleInfo(theResource);
+			info = MM::Native::GetHandleInfo(theResource);
 
 			std::memcpy(memoryPointer(info->address), *(void **)nativeHandle, size);
 		}
diff --git a/toolbox/rm.h b/toolbox/rm.h
index 428ce04..b6d30ae 100644
--- a/toolbox/rm.h
+++ b/toolbox/rm.h
@@ -3,13 +3,19 @@
 
 #include <cstdint>
 
+#include <macos/tool_return.h>
+
 namespace RM
 {
 
 	namespace Native
 	{
-		uint16_t SetResLoad(bool tf);
-		uint16_t GetResource(uint32_t type, uint16_t id, uint32_t &theHandle);
+		using MacOS::tool_return;
+		
+		tool_return<void> SetResLoad(bool tf);
+		tool_return<uint32_t> GetResource(uint32_t type, uint16_t id);
+		tool_return<void> OpenResFile(const std::string &path_name, uint16_t permissions = 0);
+		tool_return<void> CloseResFile(uint16_t refNum);
 	}
 
 	uint16_t CloseResFile(uint16_t trap);
diff --git a/toolbox/utility.cpp b/toolbox/utility.cpp
index 82d5f5f..236b80e 100644
--- a/toolbox/utility.cpp
+++ b/toolbox/utility.cpp
@@ -49,10 +49,8 @@ namespace Utility {
 		 */
 
 		uint32_t theString;
-		uint32_t theHandle;
 		uint32_t sp;
 		uint32_t length = 0;
-		uint32_t d0;
 
 		std::string s;
 
@@ -64,19 +62,12 @@ namespace Utility {
 
 		length = s.length() + 1;
 
-		// if (length) // always true...
-		{
-			uint32_t ptr;
-			d0 = MM::Native::NewHandle(s.length(), false, theHandle, ptr);
 
-			if (!d0)
-			{
-				ToolBox::WritePString(ptr, s);
-			}
-		}
+		auto rv = MM::Native::NewHandle(s.length(), false);
+		if (!rv.error()) ToolBox::WritePString(rv.value().pointer, s);
 
-		ToolReturn<4>(sp, theHandle);
-		return d0;
+		ToolReturn<4>(sp, rv.value().handle);
+		return rv.error();
 	}
 
 	// FUNCTION GetString (stringID: Integer): StringHandle;
@@ -91,17 +82,15 @@ namespace Utility {
 
 		uint16_t stringID;
 		uint32_t sp;
-		uint32_t d0;
-		uint32_t theHandle;
 
 		sp = StackFrame<2>(stringID);
 
 		Log("%04x GetString($%04x)\n", trap, stringID);
 
-		d0 = RM::Native::GetResource(0x53545220, stringID, theHandle);
+		auto rv = RM::Native::GetResource(0x53545220, stringID);
 
-		ToolReturn<4>(sp, theHandle);
-		return d0;
+		ToolReturn<4>(sp, rv.value());
+		return rv.error();
 	}
 
 	// FUNCTION BitTst (bytePtr: Ptr; bitNum: LONGINT) : BOOLEAN;