From 82ade1e3515a9b9d8ef3745ce638be857e93c8d7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Lu=C3=ADs=20Vaz=20Silva?= <ricolvs123@gmail.com>
Date: Fri, 10 Feb 2023 09:44:32 -0300
Subject: [PATCH] Implement Static Function Pointers

---
 src/common/engine/namedef.h                   |   3 +
 src/common/engine/sc_man_scanner.re           |   1 +
 src/common/engine/sc_man_tokens.h             |   1 +
 src/common/engine/serializer.cpp              |  78 ++++++
 src/common/engine/serializer.h                |   8 +
 src/common/scripting/backend/codegen.cpp      | 208 ++++++++++++---
 src/common/scripting/backend/codegen.h        |  20 ++
 src/common/scripting/backend/vmbuilder.cpp    |  53 +++-
 src/common/scripting/backend/vmbuilder.h      |   9 +-
 src/common/scripting/core/scopebarrier.cpp    |   8 +
 src/common/scripting/core/scopebarrier.h      |   3 +
 src/common/scripting/core/types.cpp           | 242 +++++++++++++++++-
 src/common/scripting/core/types.h             |  32 ++-
 src/common/scripting/frontend/ast.cpp         |  33 +++
 src/common/scripting/frontend/zcc-parse.lemon |  69 +++++
 src/common/scripting/frontend/zcc_compile.cpp |  57 +++++
 src/common/scripting/frontend/zcc_exprlist.h  |   1 +
 src/common/scripting/frontend/zcc_parser.cpp  |  38 +++
 src/common/scripting/frontend/zcc_parser.h    |  22 ++
 src/common/scripting/interface/vmnatives.cpp  |  32 +++
 src/scripting/backend/codegen_doom.cpp        |   3 +-
 wadsrc/static/zscript.txt                     |   2 +-
 wadsrc/static/zscript/engine/base.zs          |   4 +
 23 files changed, 876 insertions(+), 51 deletions(-)

diff --git a/src/common/engine/namedef.h b/src/common/engine/namedef.h
index 948228cb916..70080a96519 100644
--- a/src/common/engine/namedef.h
+++ b/src/common/engine/namedef.h
@@ -120,6 +120,7 @@ xx(Vector)
 xx(Map)
 xx(MapIterator)
 xx(Array)
+xx(Function)
 xx(Include)
 xx(Sound)
 xx(State)
@@ -190,6 +191,7 @@ xx(SetNull)
 xx(Key)
 xx(Index)
 xx(Find)
+xx(Call)
 
 // color channels
 xx(a)
@@ -269,6 +271,7 @@ xx(BuiltinRandom2)
 xx(BuiltinFRandom)
 xx(BuiltinNameToClass)
 xx(BuiltinClassCast)
+xx(BuiltinFunctionPtrCast)
 
 xx(ScreenJobRunner)
 xx(Action)
diff --git a/src/common/engine/sc_man_scanner.re b/src/common/engine/sc_man_scanner.re
index dfc3f050f0e..e5d507a28d5 100644
--- a/src/common/engine/sc_man_scanner.re
+++ b/src/common/engine/sc_man_scanner.re
@@ -169,6 +169,7 @@ std2:
 		'map'						{ RET(TK_Map); }
 		'mapiterator'				{ RET(TK_MapIterator); }
 		'array'						{ RET(TK_Array); }
+		'function'					{ RET(ParseVersion >= MakeVersion(4, 11, 0)? TK_FunctionType : TK_Identifier); }
 		'in'						{ RET(TK_In); }
 		'sizeof'					{ RET(TK_SizeOf); }
 		'alignof'					{ RET(TK_AlignOf); }
diff --git a/src/common/engine/sc_man_tokens.h b/src/common/engine/sc_man_tokens.h
index 8fb2f88e3ef..48700312517 100644
--- a/src/common/engine/sc_man_tokens.h
+++ b/src/common/engine/sc_man_tokens.h
@@ -131,6 +131,7 @@ xx(TK_Vector3,				"'vector3'")
 xx(TK_Map,					"'map'")
 xx(TK_MapIterator,			"'mapiterator'")
 xx(TK_Array,				"'array'")
+xx(TK_FunctionType,			"'function'")
 xx(TK_In,					"'in'")
 xx(TK_SizeOf,				"'sizeof'")
 xx(TK_AlignOf,				"'alignof'")
diff --git a/src/common/engine/serializer.cpp b/src/common/engine/serializer.cpp
index bb54c0d2be7..34fd6956b59 100644
--- a/src/common/engine/serializer.cpp
+++ b/src/common/engine/serializer.cpp
@@ -1656,6 +1656,84 @@ FSerializer &Serialize(FSerializer &arc, const char *key, NumericValue &value, N
 	return arc;
 }
 
+//==========================================================================
+//
+// PFunctionPointer
+//
+//==========================================================================
+
+void SerializeFunctionPointer(FSerializer &arc, const char *key, FunctionPointerValue *&p)
+{
+	if (arc.isWriting())
+	{
+		if(p)
+		{
+			arc.BeginObject(key);
+			arc("Class",p->ClassName);
+			arc("Function",p->FunctionName);
+			arc.EndObject();
+		}
+		else
+		{
+			arc.WriteKey(key);
+			arc.w->Null();
+		}
+	}
+	else
+	{
+		assert(p);
+		auto v = arc.r->FindKey(key);
+		if(!v || v->IsNull())
+		{
+			p = nullptr;
+		}
+		else if(v->IsObject())
+		{
+			arc.r->mObjects.Push(FJSONObject(v)); // BeginObject
+
+			const char * cstr;
+			arc.StringPtr("Class", cstr);
+
+			if(!cstr)
+			{
+				arc.StringPtr("Function", cstr);
+				if(!cstr)
+				{
+					Printf(TEXTCOLOR_RED "Function Pointer missing Class and Function Fields in Object\n");
+				}
+				else
+				{
+					Printf(TEXTCOLOR_RED "Function Pointer missing Class Field in Object\n");
+				}
+				arc.mErrors++;
+				arc.EndObject();
+				p = nullptr;
+				return;
+			}
+
+			p->ClassName = FString(cstr);
+			arc.StringPtr("Function", cstr);
+
+			if(!cstr)
+			{
+				Printf(TEXTCOLOR_RED "Function Pointer missing Function Field in Object\n");
+				arc.mErrors++;
+				arc.EndObject();
+				p = nullptr;
+				return;
+			}
+			p->FunctionName = FString(cstr);
+			arc.EndObject();
+		}
+		else
+		{
+			Printf(TEXTCOLOR_RED "Function Pointer is not an Object\n");
+			arc.mErrors++;
+			p = nullptr;
+		}
+	}
+}
+
 #include "renderstyle.h"
 FSerializer& Serialize(FSerializer& arc, const char* key, FRenderStyle& style, FRenderStyle* def)
 {
diff --git a/src/common/engine/serializer.h b/src/common/engine/serializer.h
index a6f74c0371c..9328f2f223b 100644
--- a/src/common/engine/serializer.h
+++ b/src/common/engine/serializer.h
@@ -54,6 +54,12 @@ struct NumericValue
 	}
 };
 
+struct FunctionPointerValue
+{
+	FString ClassName;
+	FString FunctionName;
+};
+
 
 class FSerializer
 {
@@ -235,6 +241,8 @@ FSerializer &Serialize(FSerializer &arc, const char *key, FString &sid, FString
 FSerializer &Serialize(FSerializer &arc, const char *key, NumericValue &sid, NumericValue *def);
 FSerializer &Serialize(FSerializer &arc, const char *key, struct ModelOverride &sid, struct ModelOverride *def);
 
+void SerializeFunctionPointer(FSerializer &arc, const char *key, FunctionPointerValue *&p);
+
 template <typename T/*, typename = std::enable_if_t<std::is_base_of_v<DObject, T>>*/>
 FSerializer &Serialize(FSerializer &arc, const char *key, T *&value, T **)
 {
diff --git a/src/common/scripting/backend/codegen.cpp b/src/common/scripting/backend/codegen.cpp
index 9711abf7289..24ab59d93ed 100644
--- a/src/common/scripting/backend/codegen.cpp
+++ b/src/common/scripting/backend/codegen.cpp
@@ -297,6 +297,13 @@ bool AreCompatiblePointerTypes(PType *dest, PType *source, bool forcompare)
 			if (forcompare && tocls->IsDescendantOf(fromcls)) return true;
 			return (fromcls->IsDescendantOf(tocls));
 		}
+		if(source->isFunctionPointer() && dest->isFunctionPointer())
+		{
+			auto from = static_cast<PFunctionPointer*>(source);
+			auto to = static_cast<PFunctionPointer*>(dest);
+			return to->PointedType == TypeVoid || (from->PointedType == to->PointedType && from->ArgFlags == to->ArgFlags && FScopeBarrier::CheckSidesForFunctionPointer(from->Scope, to->Scope));
+			// TODO allow narrowing argument types and widening return types via cast, ex.: Function<Actor(Object or Class<Object>)> to Function<Object(Actor or Class<Actor>)>
+		}
 	}
 	return false;
 }
@@ -8360,6 +8367,7 @@ FxExpression *FxMemberFunctionCall::Resolve(FCompileContext& ctx)
 	PContainerType *cls = nullptr;
 	bool staticonly = false;
 	bool novirtual = false;
+	bool fnptr = false;
 	bool isreadonly = false;
 
 	PContainerType *ccls = nullptr;
@@ -8977,6 +8985,22 @@ FxExpression *FxMemberFunctionCall::Resolve(FCompileContext& ctx)
 		cls = static_cast<PStruct*>(Self->ValueType);
 		Self->ValueType = NewPointer(Self->ValueType);
 	}
+	else if (Self->ValueType->isFunctionPointer())
+	{
+		auto fn = static_cast<PFunctionPointer*>(Self->ValueType);
+
+		if(MethodName == NAME_Call && fn->PointedType != TypeVoid)
+		{ // calling a Function<void> pointer isn't allowed
+			fnptr = true;
+			afd_override = fn->FakeFunction;
+		}
+		else
+		{
+			ScriptPosition.Message(MSG_ERROR, "Unknown function %s", MethodName.GetChars());
+			delete this;
+			return nullptr;
+		}
+	}
 	else
 	{
 		ScriptPosition.Message(MSG_ERROR, "Invalid expression on left hand side of %s", MethodName.GetChars());
@@ -9096,8 +9120,8 @@ FxExpression *FxMemberFunctionCall::Resolve(FCompileContext& ctx)
 	}
 
 	// do not pass the self pointer to static functions.
-	auto self = (afd->Variants[0].Flags & VARF_Method) ? Self : nullptr;
-	auto x = new FxVMFunctionCall(self, afd, ArgList, ScriptPosition, staticonly|novirtual);
+	auto self = ( fnptr || (afd->Variants[0].Flags & VARF_Method)) ? Self : nullptr;
+	auto x = new FxVMFunctionCall(self, afd, ArgList, ScriptPosition, (staticonly || novirtual) && !fnptr);
 	if (Self == self) Self = nullptr;
 	delete this;
 	return x->Resolve(ctx);
@@ -9111,7 +9135,7 @@ FxExpression *FxMemberFunctionCall::Resolve(FCompileContext& ctx)
 //==========================================================================
 
 FxVMFunctionCall::FxVMFunctionCall(FxExpression *self, PFunction *func, FArgumentList &args, const FScriptPosition &pos, bool novirtual)
-: FxExpression(EFX_VMFunctionCall, pos)
+: FxExpression(EFX_VMFunctionCall, pos) , FnPtrCall((self && self->ValueType) ? self->ValueType->isFunctionPointer() : false)
 {
 	Self = self;
 	Function = func;
@@ -9185,7 +9209,7 @@ VMFunction *FxVMFunctionCall::GetDirectFunction(PFunction *callingfunc, const Ve
 	// definition can call that function directly without wrapping
 	// it inside VM code.
 
-	if (ArgList.Size() == 0 && !(Function->Variants[0].Flags & VARF_Virtual) && CheckAccessibility(ver) && CheckFunctionCompatiblity(ScriptPosition, callingfunc, Function))
+	if (ArgList.Size() == 0 && !(Function->Variants[0].Flags & VARF_Virtual) && !FnPtrCall && CheckAccessibility(ver) && CheckFunctionCompatiblity(ScriptPosition, callingfunc, Function))
 	{
 		unsigned imp = Function->GetImplicitArgs();
 		if (Function->Variants[0].ArgFlags.Size() > imp && !(Function->Variants[0].ArgFlags[imp] & VARF_Optional)) return nullptr;
@@ -9210,7 +9234,7 @@ FxExpression *FxVMFunctionCall::Resolve(FCompileContext& ctx)
 	auto &argtypes = proto->ArgumentTypes;
 	auto &argnames = Function->Variants[0].ArgNames;
 	auto &argflags = Function->Variants[0].ArgFlags;
-	auto &defaults = Function->Variants[0].Implementation->DefaultArgs;
+	auto *defaults = FnPtrCall ? nullptr : &Function->Variants[0].Implementation->DefaultArgs;
 
 	int implicit = Function->GetImplicitArgs();
 
@@ -9278,6 +9302,12 @@ FxExpression *FxVMFunctionCall::Resolve(FCompileContext& ctx)
 
 			if (ArgList[i]->ExprType == EFX_NamedNode)
 			{
+				if(FnPtrCall)
+				{
+					ScriptPosition.Message(MSG_ERROR, "Named arguments not supported in function pointer calls");
+					delete this;
+					return nullptr;
+				}
 				if (!(flag & VARF_Optional))
 				{
 					ScriptPosition.Message(MSG_ERROR, "Cannot use a named argument here - not all required arguments have been passed.");
@@ -9327,7 +9357,7 @@ FxExpression *FxVMFunctionCall::Resolve(FCompileContext& ctx)
 							}
 							if (ntype->GetRegCount() == 1)
 							{
-								auto x = new FxConstant(ntype, defaults[i + k + skipdefs + implicit], ScriptPosition);
+								auto x = new FxConstant(ntype, (*defaults)[i + k + skipdefs + implicit], ScriptPosition);
 								ArgList.Insert(i + k, x);
 							}
 							else 
@@ -9336,7 +9366,7 @@ FxExpression *FxVMFunctionCall::Resolve(FCompileContext& ctx)
 								FxConstant *cs[4] = { nullptr };
 								for (int l = 0; l < ntype->GetRegCount(); l++)
 								{
-									cs[l] = new FxConstant(TypeFloat64, defaults[l + i + k + skipdefs + implicit], ScriptPosition);
+									cs[l] = new FxConstant(TypeFloat64, (*defaults)[l + i + k + skipdefs + implicit], ScriptPosition);
 								}
 								FxExpression *x = new FxVectorValue(cs[0], cs[1], cs[2], cs[3], ScriptPosition);
 								ArgList.Insert(i + k, x);
@@ -9473,6 +9503,7 @@ FxExpression *FxVMFunctionCall::Resolve(FCompileContext& ctx)
 	{
 		ValueType = TypeVoid;
 	}
+
 	return this;
 }
 
@@ -9498,11 +9529,14 @@ ExpEmit FxVMFunctionCall::Emit(VMFunctionBuilder *build)
 		}
 	}
 
-	VMFunction *vmfunc = Function->Variants[0].Implementation;
-	bool staticcall = ((vmfunc->VarFlags & VARF_Final) || vmfunc->VirtualIndex == ~0u || NoVirtual);
+	VMFunction *vmfunc = FnPtrCall ? nullptr : Function->Variants[0].Implementation;
+	bool staticcall = (FnPtrCall || (vmfunc->VarFlags & VARF_Final) || vmfunc->VirtualIndex == ~0u || NoVirtual);
 
 	count = 0;
-	FunctionCallEmitter emitters(vmfunc);
+
+	assert(!FnPtrCall || (FnPtrCall && Self && Self->ValueType && Self->ValueType->isFunctionPointer()));
+
+	FunctionCallEmitter emitters(FnPtrCall ? FunctionCallEmitter(PType::toFunctionPointer(Self->ValueType)) : FunctionCallEmitter(vmfunc));
 	// Emit code to pass implied parameters
 	ExpEmit selfemit;
 	if (Function->Variants[0].Flags & VARF_Method)
@@ -9546,43 +9580,56 @@ ExpEmit FxVMFunctionCall::Emit(VMFunctionBuilder *build)
 			}
 		}
 	}
+	else if (FnPtrCall)
+	{
+		assert(Self != nullptr);
+		selfemit = Self->Emit(build);
+		assert(selfemit.RegType == REGT_POINTER);
+		staticcall = false;
+	}
 	else staticcall = true;
 	// Emit code to pass explicit parameters
 	for (unsigned i = 0; i < ArgList.Size(); ++i)
 	{
 		emitters.AddParameter(build, ArgList[i]);
 	}
-	// Complete the parameter list from the defaults.
-	auto &defaults = Function->Variants[0].Implementation->DefaultArgs;
-	for (unsigned i = emitters.Count(); i < defaults.Size(); i++)
+	if(!FnPtrCall)
 	{
-		switch (defaults[i].Type)
+		// Complete the parameter list from the defaults.
+		auto &defaults = Function->Variants[0].Implementation->DefaultArgs;
+		for (unsigned i = emitters.Count(); i < defaults.Size(); i++)
 		{
-		default:
-		case REGT_INT:
-			emitters.AddParameterIntConst(defaults[i].i);
-			break;
-		case REGT_FLOAT:
-			emitters.AddParameterFloatConst(defaults[i].f);
-			break;
-		case REGT_POINTER:
-			emitters.AddParameterPointerConst(defaults[i].a);
-			break;
-		case REGT_STRING:
-			emitters.AddParameterStringConst(defaults[i].s());
-			break;
+			switch (defaults[i].Type)
+			{
+			default:
+			case REGT_INT:
+				emitters.AddParameterIntConst(defaults[i].i);
+				break;
+			case REGT_FLOAT:
+				emitters.AddParameterFloatConst(defaults[i].f);
+				break;
+			case REGT_POINTER:
+				emitters.AddParameterPointerConst(defaults[i].a);
+				break;
+			case REGT_STRING:
+				emitters.AddParameterStringConst(defaults[i].s());
+				break;
+			}
 		}
 	}
 	ArgList.DeleteAndClear();
 	ArgList.ShrinkToFit();
 
 	if (!staticcall) emitters.SetVirtualReg(selfemit.RegNum);
-	int resultcount = vmfunc->Proto->ReturnTypes.Size() == 0 ? 0 : max(AssignCount, 1);
 
-	assert((unsigned)resultcount <= vmfunc->Proto->ReturnTypes.Size());
+	PPrototype * proto = FnPtrCall ? static_cast<PPrototype*>(static_cast<PFunctionPointer*>(Self->ValueType)->PointedType) : vmfunc->Proto;
+
+	int resultcount = proto->ReturnTypes.Size() == 0 ? 0 : max(AssignCount, 1);
+
+	assert((unsigned)resultcount <= proto->ReturnTypes.Size());
 	for (int i = 0; i < resultcount; i++)
 	{
-		emitters.AddReturn(vmfunc->Proto->ReturnTypes[i]->GetRegType(), vmfunc->Proto->ReturnTypes[i]->GetRegCount());
+		emitters.AddReturn(proto->ReturnTypes[i]->GetRegType(), proto->ReturnTypes[i]->GetRegCount());
 	}
 	return emitters.EmitCall(build, resultcount > 1? &ReturnRegs : nullptr);
 }
@@ -11610,6 +11657,107 @@ ExpEmit FxClassPtrCast::Emit(VMFunctionBuilder *build)
 	return emitters.EmitCall(build);
 }
 
+//==========================================================================
+//
+//==========================================================================
+
+FxFunctionPtrCast::FxFunctionPtrCast(PFunctionPointer *ftype, FxExpression *x)
+	: FxExpression(EFX_FunctionPtrCast, x->ScriptPosition)
+{
+	ValueType = ftype;
+	basex = x;
+}
+
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+FxFunctionPtrCast::~FxFunctionPtrCast()
+{
+	SAFE_DELETE(basex);
+}
+
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+FxExpression *FxFunctionPtrCast::Resolve(FCompileContext &ctx)
+{
+	CHECKRESOLVED();
+	SAFE_RESOLVE(basex, ctx);
+
+	if (!(basex->ValueType && basex->ValueType->isFunctionPointer()))
+	{
+		delete this;
+		return nullptr;
+	}
+	auto to = static_cast<PFunctionPointer *>(ValueType);
+	auto from = static_cast<PFunctionPointer *>(basex->ValueType);
+
+	if(to->PointedType == TypeVoid)
+	{	// no need to do anything for (Function<void)(...) casts
+		basex->ValueType = ValueType;
+		auto x = basex;
+		basex = nullptr;
+		delete this;
+		return x;
+	}
+	else if(from->PointedType == TypeVoid)
+	{	// nothing to check at compile-time for casts from Function<void>
+		return this;
+	}
+	else
+	{
+		// TODO allow narrowing argument types and widening return types via cast, ex.: Function<Actor(Object or Class<Object>)> to Function<Object(Actor or Class<Actor>)>
+		ScriptPosition.Message(MSG_ERROR, "Cannot cast %s to %s. The types are incompatible.", basex->ValueType->DescriptiveName(), to->DescriptiveName());
+		delete this;
+		return nullptr;
+	}
+}
+
+//==========================================================================
+//
+// 
+//
+//==========================================================================
+
+PFunction *NativeFunctionPointerCast(PFunction *from, const PFunctionPointer *to)
+{
+	// TODO allow narrowing argument types and widening return types via cast, ex.: Function<Actor(Object or Class<Object>)> to Function<Object(Actor or Class<Actor>)>
+	return (to->PointedType == TypeVoid || (from &&
+				(  from->Variants[0].Proto == static_cast<PPrototype*>(to->PointedType)
+				&& from->Variants[0].ArgFlags == to->ArgFlags
+				&& FScopeBarrier::CheckSidesForFunctionPointer(FScopeBarrier::SideFromFlags(from->Variants[0].Flags), to->Scope)
+				))) ? from : nullptr;
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(DObject, BuiltinFunctionPtrCast, NativeFunctionPointerCast)
+{
+	PARAM_PROLOGUE;
+	PARAM_POINTER(from, PFunction);
+	PARAM_POINTER(to, PFunctionPointer);
+	ACTION_RETURN_POINTER(NativeFunctionPointerCast(from, to));
+}
+
+ExpEmit FxFunctionPtrCast::Emit(VMFunctionBuilder *build)
+{
+	ExpEmit funcptr = basex->Emit(build);
+
+	auto sym = FindBuiltinFunction(NAME_BuiltinFunctionPtrCast);
+	assert(sym);
+
+	FunctionCallEmitter emitters(sym->Variants[0].Implementation);
+	emitters.AddParameter(funcptr, false);
+	emitters.AddParameterPointerConst(ValueType);
+
+	emitters.AddReturn(REGT_POINTER);
+	return emitters.EmitCall(build);
+}
+
 //==========================================================================
 //
 // declares a single local variable (no arrays)
diff --git a/src/common/scripting/backend/codegen.h b/src/common/scripting/backend/codegen.h
index 2781adbe5a8..e0ec9f2c0f7 100644
--- a/src/common/scripting/backend/codegen.h
+++ b/src/common/scripting/backend/codegen.h
@@ -277,6 +277,7 @@ enum EFxType
 	EFX_ReturnStatement,
 	EFX_ClassTypeCast,
 	EFX_ClassPtrCast,
+	EFX_FunctionPtrCast,
 	EFX_StateByIndex,
 	EFX_RuntimeStateIndex,
 	EFX_MultiNameState,
@@ -1811,6 +1812,7 @@ class FxVMFunctionCall : public FxExpression
 	bool CheckAccessibility(const VersionInfo &ver);
 
 public:
+	const bool FnPtrCall;
 
 	FArgumentList ArgList;
 	PFunction* Function;
@@ -2120,6 +2122,24 @@ class FxClassPtrCast : public FxExpression
 //
 //==========================================================================
 
+class FxFunctionPtrCast : public FxExpression
+{
+	FxExpression *basex;
+
+public:
+
+	FxFunctionPtrCast (PFunctionPointer *ftype, FxExpression *x);
+	~FxFunctionPtrCast();
+	FxExpression *Resolve(FCompileContext&);
+	ExpEmit Emit(VMFunctionBuilder *build);
+};
+
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
 class FxNop : public FxExpression
 {
 public:
diff --git a/src/common/scripting/backend/vmbuilder.cpp b/src/common/scripting/backend/vmbuilder.cpp
index d063790d286..b64950e3441 100644
--- a/src/common/scripting/backend/vmbuilder.cpp
+++ b/src/common/scripting/backend/vmbuilder.cpp
@@ -949,6 +949,18 @@ void FFunctionBuildList::DumpJit(bool include_gzdoom_pk3)
 #endif // HAVE_VM_JIT
 }
 
+FunctionCallEmitter::FunctionCallEmitter(VMFunction *func)
+{
+	target = func;
+	is_vararg = target->VarFlags & VARF_VarArg;
+}
+
+FunctionCallEmitter::FunctionCallEmitter(class PFunctionPointer *func)
+{
+	fnptr = func;
+	is_vararg = false; // function pointers cannot point to vararg functions
+}
+
 
 void FunctionCallEmitter::AddParameter(VMFunctionBuilder *build, FxExpression *operand)
 {
@@ -959,7 +971,7 @@ void FunctionCallEmitter::AddParameter(VMFunctionBuilder *build, FxExpression *o
 		operand->ScriptPosition.Message(MSG_ERROR, "Attempted to pass a non-value");
 	}
 	numparams += where.RegCount;
-	if (target->VarFlags & VARF_VarArg)
+	if (is_vararg)
 		for (unsigned i = 0; i < where.RegCount; i++) reginfo.Push(where.RegType & REGT_TYPE);
 
 	emitters.push_back([=](VMFunctionBuilder *build) -> int
@@ -982,7 +994,7 @@ void FunctionCallEmitter::AddParameter(VMFunctionBuilder *build, FxExpression *o
 void FunctionCallEmitter::AddParameter(ExpEmit &emit, bool reference)
 {
 	numparams += emit.RegCount;
-	if (target->VarFlags & VARF_VarArg)
+	if (is_vararg)
 	{
 		if (reference) reginfo.Push(REGT_POINTER);
 		else for (unsigned i = 0; i < emit.RegCount; i++) reginfo.Push(emit.RegType & REGT_TYPE);
@@ -999,7 +1011,7 @@ void FunctionCallEmitter::AddParameter(ExpEmit &emit, bool reference)
 void FunctionCallEmitter::AddParameterPointerConst(void *konst)
 {
 	numparams++;
-	if (target->VarFlags & VARF_VarArg)
+	if (is_vararg)
 		reginfo.Push(REGT_POINTER);
 	emitters.push_back([=](VMFunctionBuilder *build) ->int
 	{
@@ -1011,7 +1023,7 @@ void FunctionCallEmitter::AddParameterPointerConst(void *konst)
 void FunctionCallEmitter::AddParameterPointer(int index, bool konst)
 {
 	numparams++;
-	if (target->VarFlags & VARF_VarArg)
+	if (is_vararg)
 		reginfo.Push(REGT_POINTER);
 	emitters.push_back([=](VMFunctionBuilder *build) ->int
 	{
@@ -1023,7 +1035,7 @@ void FunctionCallEmitter::AddParameterPointer(int index, bool konst)
 void FunctionCallEmitter::AddParameterFloatConst(double konst)
 {
 	numparams++;
-	if (target->VarFlags & VARF_VarArg)
+	if (is_vararg)
 		reginfo.Push(REGT_FLOAT);
 	emitters.push_back([=](VMFunctionBuilder *build) ->int
 	{
@@ -1035,7 +1047,7 @@ void FunctionCallEmitter::AddParameterFloatConst(double konst)
 void FunctionCallEmitter::AddParameterIntConst(int konst)
 {
 	numparams++;
-	if (target->VarFlags & VARF_VarArg)
+	if (is_vararg)
 		reginfo.Push(REGT_INT);
 	emitters.push_back([=](VMFunctionBuilder *build) ->int
 	{
@@ -1055,7 +1067,7 @@ void FunctionCallEmitter::AddParameterIntConst(int konst)
 void FunctionCallEmitter::AddParameterStringConst(const FString &konst)
 {
 	numparams++;
-	if (target->VarFlags & VARF_VarArg)
+	if (is_vararg)
 		reginfo.Push(REGT_STRING);
 	emitters.push_back([=](VMFunctionBuilder *build) ->int
 	{
@@ -1074,7 +1086,7 @@ ExpEmit FunctionCallEmitter::EmitCall(VMFunctionBuilder *build, TArray<ExpEmit>
 		paramcount += func(build);
 	}
 	assert(paramcount == numparams);
-	if (target->VarFlags & VARF_VarArg)
+	if (is_vararg)
 	{
 		// Pass a hidden type information parameter to vararg functions.
 		// It would really be nicer to actually pass real types but that'd require a far more complex interface on the compiler side than what we have.
@@ -1084,9 +1096,24 @@ ExpEmit FunctionCallEmitter::EmitCall(VMFunctionBuilder *build, TArray<ExpEmit>
 		paramcount++;
 	}
 
+	if(fnptr)
+	{
+		ExpEmit reg(build, REGT_POINTER);
+
+		assert(fnptr->Scope != -1);
+		assert(fnptr->PointedType != TypeVoid);
+		
+		// OP_LP , Load from memory. rA = *(rB + rkC)
+		// reg = &PFunction->Variants[0] -- PFunction::Variant*
+		build->Emit(OP_LP, reg.RegNum, virtualselfreg, build->GetConstantInt(offsetof(PFunction, Variants) + offsetof(FArray, Array)));
+		// reg = (&PFunction->Variants[0])->Implementation -- VMFunction*
+		build->Emit(OP_LP, reg.RegNum, reg.RegNum, build->GetConstantInt(offsetof(PFunction::Variant, Implementation)));
 
+		build->Emit(OP_CALL, reg.RegNum, paramcount, vm_jit? static_cast<PPrototype*>(fnptr->PointedType)->ReturnTypes.Size() : returns.Size());
 
-	if (virtualselfreg == -1)
+		reg.Free(build);
+	}
+	else if (virtualselfreg == -1)
 	{
 		build->Emit(OP_CALL_K, build->GetConstantAddress(target), paramcount, vm_jit ? target->Proto->ReturnTypes.Size() : returns.Size());
 	}
@@ -1110,9 +1137,13 @@ ExpEmit FunctionCallEmitter::EmitCall(VMFunctionBuilder *build, TArray<ExpEmit>
 	}
 	if (vm_jit)	// The JIT compiler needs this, but the VM interpreter does not.
 	{
-		for (unsigned i = returns.Size(); i < target->Proto->ReturnTypes.Size(); i++)
+		assert(!fnptr || fnptr->PointedType != TypeVoid);
+
+		PPrototype * proto = fnptr ? static_cast<PPrototype*>(fnptr->PointedType) : target->Proto;
+
+		for (unsigned i = returns.Size(); i < proto->ReturnTypes.Size(); i++)
 		{
-			ExpEmit reg(build, target->Proto->ReturnTypes[i]->RegType, target->Proto->ReturnTypes[i]->RegCount);
+			ExpEmit reg(build, proto->ReturnTypes[i]->RegType, proto->ReturnTypes[i]->RegCount);
 			build->Emit(OP_RESULT, 0, EncodeRegType(reg), reg.RegNum);
 			reg.Free(build);
 		}
diff --git a/src/common/scripting/backend/vmbuilder.h b/src/common/scripting/backend/vmbuilder.h
index 43ef1bc4cfb..f1c8d889f35 100644
--- a/src/common/scripting/backend/vmbuilder.h
+++ b/src/common/scripting/backend/vmbuilder.h
@@ -180,13 +180,12 @@ class FunctionCallEmitter
 	TArray<uint8_t> reginfo;
 	unsigned numparams = 0;	// This counts the number of pushed elements, which can differ from the number of emitters with vectors.
 	VMFunction *target = nullptr;
+	class PFunctionPointer *fnptr = nullptr;
 	int virtualselfreg = -1;
-
+	bool is_vararg;
 public:
-	FunctionCallEmitter(VMFunction *func)
-	{
-		target = func;
-	}
+	FunctionCallEmitter(VMFunction *func);
+	FunctionCallEmitter(class PFunctionPointer *func);
 
 	void SetVirtualReg(int virtreg)
 	{
diff --git a/src/common/scripting/core/scopebarrier.cpp b/src/common/scripting/core/scopebarrier.cpp
index 8e03f757fe5..b2744357073 100644
--- a/src/common/scripting/core/scopebarrier.cpp
+++ b/src/common/scripting/core/scopebarrier.cpp
@@ -208,6 +208,14 @@ void FScopeBarrier::AddFlags(int flags1, int flags2, const char* name)
 	}
 }
 
+bool FScopeBarrier::CheckSidesForFunctionPointer(int from, int to)
+{
+	if(to == -1) return true;
+
+	if(from == Side_Clear) from = Side_PlainData;
+	return ((from == to) || (from == Side_PlainData));
+}
+
 // these are for vmexec.h
 void FScopeBarrier::ValidateNew(PClass* cls, int outerside)
 {
diff --git a/src/common/scripting/core/scopebarrier.h b/src/common/scripting/core/scopebarrier.h
index b5eeae78fc5..08fc0a195a3 100644
--- a/src/common/scripting/core/scopebarrier.h
+++ b/src/common/scripting/core/scopebarrier.h
@@ -62,6 +62,9 @@ struct FScopeBarrier
 	// This struct is used so that the logic is in a single place.
 	void AddFlags(int flags1, int flags2, const char* name);
 
+
+	static bool CheckSidesForFunctionPointer(int from, int to);
+
 	// this is called from vmexec.h
 	static void ValidateNew(PClass* cls, int scope);
 	static void ValidateCall(PClass* selftype, VMFunction *calledfunc, int outerside);
diff --git a/src/common/scripting/core/types.cpp b/src/common/scripting/core/types.cpp
index 6543dde9e92..f7d6e3b7ffa 100644
--- a/src/common/scripting/core/types.cpp
+++ b/src/common/scripting/core/types.cpp
@@ -2816,6 +2816,232 @@ PMapIterator *NewMapIterator(PType *keyType, PType *valueType)
 	return (PMapIterator *)mapIteratorType;
 }
 
+/* PFunctionPointer *******************************************************/
+
+//==========================================================================
+//
+// PFunctionPointer - Parameterized Constructor
+//
+//==========================================================================
+
+static FString MakeFunctionPointerDescriptiveName(PPrototype * proto,const TArray<uint32_t> &ArgFlags, int scope)
+{
+	FString mDescriptiveName;
+
+	mDescriptiveName = "Function<";
+	switch(scope)
+	{
+	case FScopeBarrier::Side_PlainData:
+		mDescriptiveName += "clearscope ";
+		break;
+	case FScopeBarrier::Side_Play:
+		mDescriptiveName += "play ";
+		break;
+	case FScopeBarrier::Side_UI:
+		mDescriptiveName += "ui ";
+		break;
+	}
+	if(proto->ReturnTypes.Size() > 0)
+	{
+		mDescriptiveName += proto->ReturnTypes[0]->DescriptiveName();
+
+		const unsigned n = proto->ReturnTypes.Size();
+		for(unsigned i = 1; i < n; i++)
+		{
+			mDescriptiveName += ", ";
+			mDescriptiveName += proto->ReturnTypes[i]->DescriptiveName();
+		}
+		mDescriptiveName += " (";
+	}
+	else
+	{
+		mDescriptiveName += "void (";
+	}
+	if(proto->ArgumentTypes.Size() > 0)
+	{
+		if(ArgFlags[0] == VARF_Out) mDescriptiveName += "out ";
+		mDescriptiveName += proto->ArgumentTypes[0]->DescriptiveName();
+		const unsigned n = proto->ArgumentTypes.Size();
+		for(unsigned i = 1; i < n; i++)
+		{
+			mDescriptiveName += ", ";
+			if(ArgFlags[i] == VARF_Out) mDescriptiveName += "out ";
+			mDescriptiveName += proto->ArgumentTypes[i]->DescriptiveName();
+		}
+		mDescriptiveName += ")>";
+	}
+	else
+	{
+		mDescriptiveName += "void)>";
+	}
+
+	return mDescriptiveName;
+}
+
+PFunctionPointer::PFunctionPointer(PPrototype * proto, TArray<uint32_t> && argflags, int scope)
+	: PPointer(proto ? (PType*) proto : TypeVoid, false), ArgFlags(std::move(argflags)), Scope(scope)
+{
+	if(!proto)
+	{
+		mDescriptiveName = "Function<void>";
+	}
+	else
+	{
+		mDescriptiveName = MakeFunctionPointerDescriptiveName(proto, ArgFlags, scope);
+	}
+
+	Flags |= TYPE_FunctionPointer;
+
+	if(proto)
+	{
+		assert(Scope != -1); // for now, a scope is always required
+
+		TArray<FName> ArgNames;
+		TArray<uint32_t> ArgFlags2(ArgFlags); // AddVariant calls std::move on this, so it needs to be a copy,
+											  // but it takes it as a regular reference, so it needs to be a full variable instead of a temporary
+		ArgNames.Resize(ArgFlags.Size());
+		FakeFunction = Create<PFunction>();
+		FakeFunction->AddVariant(proto, ArgFlags2, ArgNames, nullptr, FScopeBarrier::FlagsFromSide(Scope), 0);
+	}
+	else
+	{
+		FakeFunction = nullptr;
+	}
+}
+
+void PFunctionPointer::WriteValue(FSerializer &ar, const char *key, const void *addr) const
+{
+	auto p = *(const PFunction**)(addr);
+	if(p)
+	{
+		FunctionPointerValue val;
+		FunctionPointerValue *fpv = &val;
+		val.ClassName = FString((p->OwningClass ? p->OwningClass->TypeName : NAME_None).GetChars());
+		val.FunctionName = FString(p->SymbolName.GetChars());
+		SerializeFunctionPointer(ar, key, fpv);
+	}
+	else
+	{
+		FunctionPointerValue *fpv = nullptr;
+		SerializeFunctionPointer(ar, key, fpv);
+	}
+}
+
+PFunction *NativeFunctionPointerCast(PFunction *from, const PFunctionPointer *to);
+
+bool PFunctionPointer::ReadValue(FSerializer &ar, const char *key, void *addr) const
+{
+	FunctionPointerValue val;
+	FunctionPointerValue *fpv = &val;
+	SerializeFunctionPointer(ar, key, fpv);
+
+	PFunction ** fn = (PFunction**)(addr);
+
+	if(fpv)
+	{
+		auto cls = PClass::FindClass(val.ClassName);
+		if(!cls)
+		{
+			*fn = nullptr;
+			Printf(TEXTCOLOR_RED "Function Pointer ('%s::%s'): '%s' is not a valid class\n",
+				val.ClassName.GetChars(),
+				val.FunctionName.GetChars(),
+				val.ClassName.GetChars()
+			);
+			ar.mErrors++;
+			return false;
+		}
+		auto sym = cls->FindSymbol(FName(val.FunctionName), true);
+		if(!sym)
+		{
+			*fn = nullptr;
+			Printf(TEXTCOLOR_RED "Function Pointer ('%s::%s'): symbol '%s' does not exist in class '%s'\n",
+				val.ClassName.GetChars(),
+				val.FunctionName.GetChars(),
+				val.FunctionName.GetChars(),
+				val.ClassName.GetChars()
+			);
+			ar.mErrors++;
+			return false;
+		}
+		PFunction* p = dyn_cast<PFunction>(sym);
+		if(!p)
+		{
+			*fn = nullptr;
+			Printf(TEXTCOLOR_RED "Function Pointer (%s::%s): symbol '%s' in class '%s' is a variable, not a function\n",
+				val.ClassName.GetChars(),
+				val.FunctionName.GetChars(),
+				val.FunctionName.GetChars(),
+				val.ClassName.GetChars()
+			);
+			ar.mErrors++;
+			return false;
+		}
+		else if(p->GetImplicitArgs() > 0)
+		{
+			*fn = nullptr;
+			Printf(TEXTCOLOR_RED "Function Pointer (%s::%s): function '%s' in class '%s' is %s, not a static function\n",
+				val.ClassName.GetChars(),
+				val.FunctionName.GetChars(),
+				val.FunctionName.GetChars(),
+				val.ClassName.GetChars(),
+				(p->GetImplicitArgs() == 1 ? "a method" : "an action function")
+			);
+			ar.mErrors++;
+			return false;
+		}
+		*fn = NativeFunctionPointerCast(p, this);
+		if(!*fn)
+		{
+			FString fn_name = MakeFunctionPointerDescriptiveName(p->Variants[0].Proto,p->Variants[0].ArgFlags, FScopeBarrier::SideFromFlags(p->Variants[0].Flags));
+			Printf(TEXTCOLOR_RED "Function Pointer (%s::%s) has incompatible type (Pointer is '%s', Function is '%s')\n",
+						val.ClassName.GetChars(),
+						val.FunctionName.GetChars(),
+						fn_name.GetChars(),
+						mDescriptiveName.GetChars()
+			);
+			ar.mErrors++;
+			return false;
+		}
+		return true;
+	}
+	else
+	{
+		*fn = nullptr;
+	}
+	return true;
+}
+
+bool PFunctionPointer::IsMatch(intptr_t id1, intptr_t id2) const
+{
+	const PPrototype * proto = (const PPrototype*) id1;
+	const PFunctionPointer::FlagsAndScope * flags_and_scope = (const PFunctionPointer::FlagsAndScope *) id2;
+	return (proto == (PointedType == TypeVoid ? nullptr : PointedType))
+		&& (Scope == flags_and_scope->Scope)
+		&& (ArgFlags == *flags_and_scope->ArgFlags);
+}
+
+void PFunctionPointer::GetTypeIDs(intptr_t &id1, intptr_t &id2) const
+{	//NOT SUPPORTED
+	assert(0 && "GetTypeIDs not supported for PFunctionPointer");
+}
+
+PFunctionPointer * NewFunctionPointer(PPrototype * proto, TArray<uint32_t> && argflags, int scope)
+{
+	size_t bucket;
+
+	PFunctionPointer::FlagsAndScope flags_and_scope { &argflags, scope };
+
+	PType *fn = TypeTable.FindType(NAME_Function, (intptr_t)proto, (intptr_t)&flags_and_scope, &bucket);
+	if (fn == nullptr)
+	{
+		fn = new PFunctionPointer(proto, std::move(argflags), scope);
+		flags_and_scope.ArgFlags = &static_cast<PFunctionPointer *>(fn)->ArgFlags;
+		TypeTable.AddType(fn, NAME_Function, (intptr_t)proto, (intptr_t)&flags_and_scope, bucket);
+	}
+	return (PFunctionPointer *)fn;
+}
+
 /* PStruct ****************************************************************/
 
 //==========================================================================
@@ -3225,13 +3451,13 @@ size_t FTypeTable::Hash(FName p1, intptr_t p2, intptr_t p3)
 	// to transform this into a ROR or ROL.
 	i1 = (i1 >> (sizeof(size_t)*4)) | (i1 << (sizeof(size_t)*4));
 
-	if (p1 != NAME_Prototype)
+	if (p1 != NAME_Prototype && p1 != NAME_Function)
 	{
 		size_t i2 = (size_t)p2;
 		size_t i3 = (size_t)p3;
 		return (~i1 ^ i2) + i3 * 961748927;	// i3 is multiplied by a prime
 	}
-	else
+	else if(p1 == NAME_Prototype)
 	{ // Prototypes need to hash the TArrays at p2 and p3
 		const TArray<PType *> *a2 = (const TArray<PType *> *)p2;
 		const TArray<PType *> *a3 = (const TArray<PType *> *)p3;
@@ -3245,6 +3471,18 @@ size_t FTypeTable::Hash(FName p1, intptr_t p2, intptr_t p3)
 		}
 		return i1;
 	}
+	else // if(p1 == NAME_Function)
+	{ // functions need custom hashing as well
+		size_t i2 = (size_t)p2;
+		const PFunctionPointer::FlagsAndScope * flags_and_scope = (const PFunctionPointer::FlagsAndScope *) p3;
+		const TArray<uint32_t> * a3 = flags_and_scope->ArgFlags;
+		i1 = (~i1 ^ i2);
+		for (unsigned i = 0; i < a3->Size(); ++i)
+		{
+			i1 = (i1 * 961748927) + (size_t)((*a3)[i]);
+		}
+		return (i1 * 961748927) + (size_t)flags_and_scope->Scope;
+	}
 }
 
 //==========================================================================
diff --git a/src/common/scripting/core/types.h b/src/common/scripting/core/types.h
index 789cc7d3e43..ebfaf7172d9 100644
--- a/src/common/scripting/core/types.h
+++ b/src/common/scripting/core/types.h
@@ -66,6 +66,7 @@ enum
 class PContainerType;
 class PPointer;
 class PClassPointer;
+class PFunctionPointer;
 class PArray;
 class PStruct;
 class PClassType;
@@ -86,6 +87,7 @@ class PType : public PTypeBase
 		TYPE_ObjectPointer = 64,
 		TYPE_ClassPointer = 128,
 		TYPE_Array = 256,
+		TYPE_FunctionPointer = 512,
 
 		TYPE_IntCompatible = TYPE_Int | TYPE_IntNotInt,	// must be the combination of all flags that are subtypes of int and can be cast to an int.
 	};
@@ -194,9 +196,10 @@ class PType : public PTypeBase
 	bool isIntCompatible() const { return !!(Flags & TYPE_IntCompatible); }
 	bool isFloat() const { return !!(Flags & TYPE_Float); }
 	bool isPointer() const { return !!(Flags & TYPE_Pointer); }
-	bool isRealPointer() const { return (Flags & (TYPE_Pointer|TYPE_ClassPointer)) == TYPE_Pointer; }	// This excludes class pointers which use their PointedType differently
+	bool isRealPointer() const { return (Flags & (TYPE_Pointer | TYPE_ClassPointer | TYPE_FunctionPointer)) == TYPE_Pointer; }	// This excludes class and function pointers which use their PointedType differently
 	bool isObjectPointer() const { return !!(Flags & TYPE_ObjectPointer); }
 	bool isClassPointer() const { return !!(Flags & TYPE_ClassPointer); }
+	bool isFunctionPointer() const { return !!(Flags & TYPE_FunctionPointer); }
 	bool isEnum() const { return TypeTableType == NAME_Enum; }
 	bool isArray() const { return !!(Flags & TYPE_Array); }
 	bool isStaticArray() const { return TypeTableType == NAME_StaticArray; }
@@ -210,6 +213,7 @@ class PType : public PTypeBase
 	PContainerType *toContainer() { return isContainer() ? (PContainerType*)this : nullptr; }
 	PPointer *toPointer() { return isPointer() ? (PPointer*)this : nullptr; }
 	static PClassPointer *toClassPointer(PType *t) { return t && t->isClassPointer() ? (PClassPointer*)t : nullptr; }
+	static PFunctionPointer *toFunctionPointer(PType *t) { return t && t->isFunctionPointer() ? (PFunctionPointer*)t : nullptr; }
 	static PClassType *toClass(PType *t) { return t && t->isClass() ? (PClassType*)t : nullptr; }
 };
 
@@ -595,6 +599,31 @@ class PMapIterator : public PCompoundType
 	void DestroyValue(void *addr) const override;
 };
 
+class PFunctionPointer : public PPointer
+{
+public:
+	//PointedType = PPrototype or TypeVoid
+	PFunctionPointer(PPrototype * proto, TArray<uint32_t> &&argflags, int scope);
+
+	TArray<uint32_t> ArgFlags;
+	int Scope;
+
+	PFunction *FakeFunction; // used for type checking in FxFunctionCall
+
+	void WriteValue(FSerializer &ar, const char *key, const void *addr) const override;
+	bool ReadValue(FSerializer &ar, const char *key, void *addr) const override;
+
+
+	struct FlagsAndScope
+	{ // used for IsMatch's id2
+		TArray<uint32_t> * ArgFlags;
+		int Scope;
+	};
+
+	bool IsMatch(intptr_t id1, intptr_t id2) const override;
+	void GetTypeIDs(intptr_t &id1, intptr_t &id2) const override; //NOT SUPPORTED
+};
+
 class PStruct : public PContainerType
 {
 public:
@@ -657,6 +686,7 @@ PMapIterator *NewMapIterator(PType *keytype, PType *valuetype);
 PArray *NewArray(PType *type, unsigned int count);
 PStaticArray *NewStaticArray(PType *type);
 PDynArray *NewDynArray(PType *type);
+PFunctionPointer *NewFunctionPointer(PPrototype * proto, TArray<uint32_t> && argflags, int scope);
 PPointer *NewPointer(PType *type, bool isconst = false);
 PPointer *NewPointer(PClass *type, bool isconst = false);
 PClassPointer *NewClassPointer(PClass *restrict);
diff --git a/src/common/scripting/frontend/ast.cpp b/src/common/scripting/frontend/ast.cpp
index 50e1c2e9f1e..2841c164312 100644
--- a/src/common/scripting/frontend/ast.cpp
+++ b/src/common/scripting/frontend/ast.cpp
@@ -521,6 +521,26 @@ static void PrintDynArrayType(FLispString &out, const ZCC_TreeNode *node)
 	out.Close();
 }
 
+static void PrintFuncPtrParamDecl(FLispString &out, const ZCC_TreeNode *node)
+{
+	ZCC_FuncPtrParamDecl *dnode = (ZCC_FuncPtrParamDecl *)node;
+	out.Break();
+	out.Open("func-ptr-param-decl");
+	PrintNodes(out, dnode->Type);
+	out.AddHex(dnode->Flags);
+	out.Close();
+}
+
+static void PrintFuncPtrType(FLispString &out, const ZCC_TreeNode *node){
+	ZCC_FuncPtrType *dnode = (ZCC_FuncPtrType *)node;
+	out.Break();
+	out.Open("func-ptr-type");
+	PrintNodes(out, dnode->RetType);
+	PrintNodes(out, dnode->Params);
+	out.AddHex(dnode->Scope);
+	out.Close();
+}
+
 static void PrintClassType(FLispString &out, const ZCC_TreeNode *node)
 {
 	ZCC_ClassType *tnode = (ZCC_ClassType *)node;
@@ -628,6 +648,16 @@ static void PrintExprClassCast(FLispString &out, const ZCC_TreeNode *node)
 	out.Close();
 }
 
+static void PrintExprFunctionPtrCast(FLispString &out, const ZCC_TreeNode *node)
+{
+	ZCC_FunctionPtrCast *enode = (ZCC_FunctionPtrCast *)node;
+	assert(enode->Operation == PEX_FunctionPtrCast);
+	out.Open("expr-func-ptr-cast");
+	PrintNodes(out, enode->PtrType, false);
+	PrintNodes(out, enode->Expr, false);
+	out.Close();
+}
+
 static void PrintStaticArray(FLispString &out, const ZCC_TreeNode *node)
 {
 	ZCC_StaticArrayStatement *enode = (ZCC_StaticArrayStatement *)node;
@@ -976,6 +1006,8 @@ static const NodePrinterFunc TreeNodePrinter[] =
 	PrintMapType,
 	PrintMapIteratorType,
 	PrintDynArrayType,
+	PrintFuncPtrParamDecl,
+	PrintFuncPtrType,
 	PrintClassType,
 	PrintExpression,
 	PrintExprID,
@@ -1011,6 +1043,7 @@ static const NodePrinterFunc TreeNodePrinter[] =
 	PrintVectorInitializer,
 	PrintDeclFlags,
 	PrintExprClassCast,
+	PrintExprFunctionPtrCast,
 	PrintStaticArrayState,
 	PrintProperty,
 	PrintFlagDef,
diff --git a/src/common/scripting/frontend/zcc-parse.lemon b/src/common/scripting/frontend/zcc-parse.lemon
index 295c58dd9af..a222afa608c 100644
--- a/src/common/scripting/frontend/zcc-parse.lemon
+++ b/src/common/scripting/frontend/zcc-parse.lemon
@@ -988,6 +988,63 @@ aggregate_type(X) ::= ARRAY(T) LT type_or_array(A) GT.							/* TArray<type> */
 	X = arr;
 }
 
+aggregate_type(X) ::= func_ptr_type(A). { X = A; /*X-overwrites-A*/ }
+
+%type func_ptr_type {ZCC_FuncPtrType *}
+%type func_ptr_params {ZCC_FuncPtrParamDecl *}
+%type func_ptr_param_list {ZCC_FuncPtrParamDecl *}
+%type func_ptr_param {ZCC_FuncPtrParamDecl *}
+
+//fn_ptr_flag(X) ::= .				{ X.Int = 0; }	//implicit scope not allowed
+fn_ptr_flag(X) ::= UI.				{ X.Int = ZCC_UIFlag; }
+fn_ptr_flag(X) ::= PLAY.			{ X.Int = ZCC_Play; }
+fn_ptr_flag(X) ::= CLEARSCOPE.		{ X.Int = ZCC_ClearScope; }
+//fn_ptr_flag(X) ::= VIRTUALSCOPE.	{ X.Int = ZCC_VirtualScope; }	//virtual scope not allowed
+
+
+func_ptr_type(X) ::= FNTYPE(T) LT fn_ptr_flag(F) type_list_or_void(A) LPAREN func_ptr_params(B) RPAREN GT. /* Function<...(...)> */
+{
+	NEW_AST_NODE(FuncPtrType,fn_ptr,T);
+	fn_ptr->RetType = A;
+	fn_ptr->Params = B;
+	fn_ptr->Scope = F.Int;
+	X = fn_ptr;
+}
+
+func_ptr_type(X) ::= FNTYPE(T) LT VOID GT. /* Function<void> */
+{
+	NEW_AST_NODE(FuncPtrType,fn_ptr,T);
+	fn_ptr->RetType = nullptr;
+	fn_ptr->Params = nullptr;
+	fn_ptr->Scope = -1;
+	X = fn_ptr;
+}
+
+func_ptr_params(X) ::= .	/* empty */			{ X = NULL; }
+func_ptr_params(X) ::= VOID.					{ X = NULL; }
+func_ptr_params(X) ::= func_ptr_param_list(X).
+
+//	varargs function pointers not currently supported
+//func_ptr_params(X) ::= func_ptr_param_list(A) COMMA ELLIPSIS.
+//{
+//	NEW_AST_NODE(FuncPtrParamDecl,parm,stat->sc->GetMessageLine());
+//	parm->Type = nullptr;
+//	parm->Flags = 0;
+//	X = A; /*X-overwrites-A*/ 
+//	AppendTreeNodeSibling(X, parm);
+//}
+
+func_ptr_param_list(X) ::= func_ptr_param(X).
+func_ptr_param_list(X) ::= func_ptr_param_list(A) COMMA func_ptr_param(B).	{ X = A; /*X-overwrites-A*/ AppendTreeNodeSibling(X, B); }
+
+func_ptr_param(X) ::= func_param_flags(A) type(B).
+{
+	NEW_AST_NODE(FuncPtrParamDecl,parm,A.SourceLoc ? A.SourceLoc : B->SourceLoc);
+	parm->Type = B;
+	parm->Flags = A.Int;
+	X = parm;
+}
+
 aggregate_type(X) ::= CLASS(T) class_restrictor(A).							/* class<type> */
 {
 	NEW_AST_NODE(ClassType,cls,T);
@@ -1408,6 +1465,17 @@ primary(X) ::= LPAREN CLASS LT IDENTIFIER(A) GT RPAREN LPAREN func_expr_list(B)
 	expr->Parameters = B;
 	X = expr;
 }
+
+primary(X) ::= LPAREN func_ptr_type(A) RPAREN LPAREN expr(B) RPAREN. [DOT]		// function pointer type cast
+{
+	NEW_AST_NODE(FunctionPtrCast, expr, A);
+	expr->Operation = PEX_FunctionPtrCast;
+	A->ArraySize = NULL;
+	expr->PtrType = A;
+	expr->Expr = B;
+	X = expr;
+}
+
 primary(X) ::= primary(A) LBRACKET expr(B) RBRACKET. [DOT]				// Array access
 {
 	NEW_AST_NODE(ExprBinary, expr, B);
@@ -1417,6 +1485,7 @@ primary(X) ::= primary(A) LBRACKET expr(B) RBRACKET. [DOT]				// Array access
 	expr->Right = B;
 	X = expr;
 }
+
 primary(X) ::= primary(A) DOT IDENTIFIER(B).							// Member access
 {
 	NEW_AST_NODE(ExprMemberAccess, expr, B);
diff --git a/src/common/scripting/frontend/zcc_compile.cpp b/src/common/scripting/frontend/zcc_compile.cpp
index fbe3d80ddce..bcfcde57ae4 100644
--- a/src/common/scripting/frontend/zcc_compile.cpp
+++ b/src/common/scripting/frontend/zcc_compile.cpp
@@ -2017,6 +2017,52 @@ PType *ZCCCompiler::DetermineType(PType *outertype, ZCC_TreeNode *field, FName n
 		}
 		break;
 	}
+	case AST_FuncPtrType:
+	{
+		auto fn = static_cast<ZCC_FuncPtrType*>(ztype);
+
+		if(fn->Scope == -1)
+		{	// Function<void>
+			retval = NewFunctionPointer(nullptr, {}, -1);
+		}
+		else
+		{
+			TArray<PType*> returns;
+			TArray<PType*> args;
+			TArray<uint32_t> argflags;
+
+			if(auto *t = fn->RetType; t != nullptr) do {
+				returns.Push(DetermineType(outertype, field, name, t, false, false));
+			} while( (t = (ZCC_Type *)t->SiblingNext) != fn->RetType);
+			
+			if(auto *t = fn->Params; t != nullptr) do {
+				args.Push(DetermineType(outertype, field, name, t->Type, false, false));
+				argflags.Push(t->Flags == ZCC_Out ? VARF_Out : 0);
+			} while( (t = (ZCC_FuncPtrParamDecl *) t->SiblingNext) != fn->Params);
+			
+			auto proto = NewPrototype(returns,args);
+			switch(fn->Scope)
+			{ // only play/ui/clearscope functions are allowed, no data or virtual scope functions
+			case ZCC_Play:
+				fn->Scope = FScopeBarrier::Side_Play;
+				break;
+			case ZCC_UIFlag:
+				fn->Scope = FScopeBarrier::Side_UI;
+				break;
+			case ZCC_ClearScope:
+				fn->Scope = FScopeBarrier::Side_PlainData;
+				break;
+			case 0:
+				fn->Scope = -1;
+				break;
+			default:
+				Error(field, "Invalid Scope for Function Pointer");
+				break;
+			}
+			retval = NewFunctionPointer(proto, std::move(argflags), fn->Scope);
+		}
+		break;
+	}
 	case AST_ClassType:
 	{
 		auto ctype = static_cast<ZCC_ClassType *>(ztype);
@@ -2985,6 +3031,17 @@ FxExpression *ZCCCompiler::ConvertNode(ZCC_TreeNode *ast, bool substitute)
 		return new FxClassPtrCast(cls, ConvertNode(cc->Parameters));
 	}
 
+	case AST_FunctionPtrCast:
+	{
+		auto cast = static_cast<ZCC_FunctionPtrCast *>(ast);
+
+		auto type = DetermineType(ConvertClass, cast, NAME_None, cast->PtrType, false, false);
+		assert(type->isFunctionPointer());
+		auto ptrType = static_cast<PFunctionPointer*>(type);
+
+		return new FxFunctionPtrCast(ptrType, ConvertNode(cast->Expr));
+	}
+
 	case AST_StaticArrayStatement:
 	{
 		auto sas = static_cast<ZCC_StaticArrayStatement *>(ast);
diff --git a/src/common/scripting/frontend/zcc_exprlist.h b/src/common/scripting/frontend/zcc_exprlist.h
index faf6af6a43d..f05758379a2 100644
--- a/src/common/scripting/frontend/zcc_exprlist.h
+++ b/src/common/scripting/frontend/zcc_exprlist.h
@@ -9,6 +9,7 @@ xx(FuncCall,		'(')
 xx(ArrayAccess,		TK_Array)
 xx(MemberAccess,	'.')
 xx(ClassCast,		TK_Class)
+xx(FunctionPtrCast,	TK_FunctionType)
 xx(TypeRef,			TK_Class)
 xx(Vector,			TK_Vector2)
 
diff --git a/src/common/scripting/frontend/zcc_parser.cpp b/src/common/scripting/frontend/zcc_parser.cpp
index e689d424949..24b2ecb1f3d 100644
--- a/src/common/scripting/frontend/zcc_parser.cpp
+++ b/src/common/scripting/frontend/zcc_parser.cpp
@@ -222,6 +222,7 @@ static void InitTokenMap()
 	TOKENDEF2(TK_Map,			ZCC_MAP,		NAME_Map);
 	TOKENDEF2(TK_MapIterator,	ZCC_MAPITERATOR,NAME_MapIterator);
 	TOKENDEF2(TK_Array,			ZCC_ARRAY,		NAME_Array);
+	TOKENDEF2(TK_FunctionType,	ZCC_FNTYPE,		NAME_Function);
 	TOKENDEF2(TK_Include,		ZCC_INCLUDE,	NAME_Include);
 	TOKENDEF (TK_Void,			ZCC_VOID);
 	TOKENDEF (TK_True,			ZCC_TRUE);
@@ -925,6 +926,29 @@ ZCC_TreeNode *TreeNodeDeepCopy_Internal(ZCC_AST *ast, ZCC_TreeNode *orig, bool c
 		break;
 	}
 
+	case AST_FuncPtrParamDecl:
+	{
+		TreeNodeDeepCopy_Start(FuncPtrParamDecl);
+
+		// ZCC_FuncPtrParamDecl
+		copy->Type = static_cast<ZCC_Type *>(TreeNodeDeepCopy_Internal(ast, origCasted->Type, true, copiedNodesList));
+		copy->Flags = origCasted->Flags;
+
+		break;
+	}
+
+	case AST_FuncPtrType:
+	{
+		TreeNodeDeepCopy_Start(FuncPtrType);
+
+		// ZCC_FuncPtrType
+		copy->RetType = static_cast<ZCC_Type *>(TreeNodeDeepCopy_Internal(ast, origCasted->RetType, true, copiedNodesList));
+		copy->Params = static_cast<ZCC_FuncPtrParamDecl *>(TreeNodeDeepCopy_Internal(ast, origCasted->Params, true, copiedNodesList));
+		copy->Scope = origCasted->Scope;
+
+		break;
+	}
+
 	case AST_ClassType:
 	{
 		TreeNodeDeepCopy_Start(ClassType);
@@ -1371,7 +1395,21 @@ ZCC_TreeNode *TreeNodeDeepCopy_Internal(ZCC_AST *ast, ZCC_TreeNode *orig, bool c
 
 		break;
 	}
+	
+	case AST_FunctionPtrCast:
+	{
+		TreeNodeDeepCopy_Start(FunctionPtrCast);
+
+		// ZCC_Expression
+		copy->Operation = origCasted->Operation;
+		copy->Type = origCasted->Type;
+		// ZCC_FunctionPtrCast
+		copy->PtrType = static_cast<ZCC_FuncPtrType *>(TreeNodeDeepCopy_Internal(ast, origCasted->PtrType, true, copiedNodesList));
+		copy->Expr = static_cast<ZCC_Expression *>(TreeNodeDeepCopy_Internal(ast, origCasted->Expr, true, copiedNodesList));
 
+		break;
+	}
+	
 	case AST_StaticArrayStatement:
 	{
 		TreeNodeDeepCopy_Start(StaticArrayStatement);
diff --git a/src/common/scripting/frontend/zcc_parser.h b/src/common/scripting/frontend/zcc_parser.h
index e4e4ea36352..c9c1a2933d1 100644
--- a/src/common/scripting/frontend/zcc_parser.h
+++ b/src/common/scripting/frontend/zcc_parser.h
@@ -101,6 +101,8 @@ enum EZCCTreeNodeType
 	AST_MapType,
 	AST_MapIteratorType,
 	AST_DynArrayType,
+	AST_FuncPtrParamDecl,
+	AST_FuncPtrType,
 	AST_ClassType,
 	AST_Expression,
 	AST_ExprID,
@@ -136,6 +138,7 @@ enum EZCCTreeNodeType
 	AST_VectorValue,
 	AST_DeclFlags,
 	AST_ClassCast,
+	AST_FunctionPtrCast,
 	AST_StaticArrayStatement,
 	AST_Property,
 	AST_FlagDef,
@@ -382,6 +385,19 @@ struct ZCC_DynArrayType : ZCC_Type
 	ZCC_Type *ElementType;
 };
 
+struct ZCC_FuncPtrParamDecl : ZCC_TreeNode
+{
+	ZCC_Type *Type;
+	int Flags;
+};
+
+struct ZCC_FuncPtrType : ZCC_Type
+{
+	ZCC_Type *RetType;
+	ZCC_FuncPtrParamDecl *Params;
+	int Scope;
+};
+
 struct ZCC_ClassType : ZCC_Type
 {
 	ZCC_Identifier *Restriction;
@@ -428,6 +444,12 @@ struct ZCC_ClassCast : ZCC_Expression
 	ZCC_FuncParm *Parameters;
 };
 
+struct ZCC_FunctionPtrCast : ZCC_Expression
+{
+	ZCC_FuncPtrType *PtrType;
+	ZCC_Expression *Expr;
+};
+
 struct ZCC_ExprMemberAccess : ZCC_Expression
 {
 	ZCC_Expression *Left;
diff --git a/src/common/scripting/interface/vmnatives.cpp b/src/common/scripting/interface/vmnatives.cpp
index daed2f091d4..00e110b718c 100644
--- a/src/common/scripting/interface/vmnatives.cpp
+++ b/src/common/scripting/interface/vmnatives.cpp
@@ -1348,3 +1348,35 @@ DEFINE_ACTION_FUNCTION_NATIVE(_QuatStruct, Inverse, QuatInverse)
 	QuatInverse(self->X, self->Y, self->Z, self->W, &quat);
 	ACTION_RETURN_QUAT(quat);
 }
+
+PFunction * FindFunctionPointer(PClass * cls, int fn_name)
+{
+	auto fn = dyn_cast<PFunction>(cls->FindSymbol(ENamedName(fn_name), true));
+	return (fn && fn->GetImplicitArgs() == 0) ? fn : nullptr;
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(DObject, FindFunction, FindFunctionPointer)
+{
+	PARAM_PROLOGUE;
+	PARAM_CLASS(cls, DObject);
+	PARAM_NAME(fn);
+
+	ACTION_RETURN_POINTER(FindFunctionPointer(cls, fn.GetIndex()));
+}
+
+/*
+PFunction * FindMethodPointer(PClass * cls, int fn_name)
+{
+	auto fn = dyn_cast<PFunction>(cls->FindSymbol(ENamedName(fn_name), true));
+	return (fn && fn->GetImplicitArgs() == 1) ? fn : nullptr;
+}
+
+DEFINE_ACTION_FUNCTION_NATIVE(DObject, FindMethod, FindMethodPointer)
+{
+	PARAM_PROLOGUE;
+	PARAM_CLASS(cls, DObject);
+	PARAM_NAME(fn);
+
+	ACTION_RETURN_POINTER(FindMethodPointer(cls, fn.GetIndex()));
+}
+*/
diff --git a/src/scripting/backend/codegen_doom.cpp b/src/scripting/backend/codegen_doom.cpp
index f93422e30b8..7aa0474c811 100644
--- a/src/scripting/backend/codegen_doom.cpp
+++ b/src/scripting/backend/codegen_doom.cpp
@@ -309,7 +309,8 @@ static bool UnravelVarArgAJump(FxVMFunctionCall *func, FCompileContext &ctx)
 static bool AJumpProcessing(FxVMFunctionCall *func, FCompileContext &ctx)
 {
 	// Unfortunately the PrintableName is the only safe thing to catch this special case here.
-	if (stricmp(func->Function->Variants[0].Implementation->QualifiedName, "Actor.A_Jump") == 0)
+    // [RL0] It's not valid to access Variant::Implementation on function pointer calls, so skip this
+	if (!func->FnPtrCall && stricmp(func->Function->Variants[0].Implementation->QualifiedName, "Actor.A_Jump") == 0)
 	{
 		// Unravel the varargs part of this function here so that the VM->native interface does not have to deal with it anymore.
 		if (func->ArgList.Size() > 2)
diff --git a/wadsrc/static/zscript.txt b/wadsrc/static/zscript.txt
index 409acc2e3fb..27888cca959 100644
--- a/wadsrc/static/zscript.txt
+++ b/wadsrc/static/zscript.txt
@@ -1,4 +1,4 @@
-version "4.10"
+version "4.11"
 
 // Generic engine code
 #include "zscript/engine/base.zs"
diff --git a/wadsrc/static/zscript/engine/base.zs b/wadsrc/static/zscript/engine/base.zs
index dd9813ae6bd..dae12d37bb3 100644
--- a/wadsrc/static/zscript/engine/base.zs
+++ b/wadsrc/static/zscript/engine/base.zs
@@ -748,11 +748,15 @@ class Object native
 	private native static void BuiltinRandomSeed(voidptr rng, int seed);
 	private native static Class<Object> BuiltinNameToClass(Name nm, Class<Object> filter);
 	private native static Object BuiltinClassCast(Object inptr, Class<Object> test);
+	private native static Function<void> BuiltinFunctionPtrCast(Function<void> inptr, voidptr newtype);
 	
 	native static uint MSTime();
 	native static double MSTimeF();
 	native vararg static void ThrowAbortException(String fmt, ...);
 
+	native static Function<void> FindFunction(Class<Object> cls, Name fn);
+	//native static Method<void> FindMethod(Class<Object> cls, Name fn);
+
 	native virtualscope void Destroy();
 
 	// This does not call into the native method of the same name to avoid problems with objects that get garbage collected late on shutdown.