- declared most native getters in Actor as const.

- made the self pointer of const functions readonly.

This seems to work fine. Both calling a non-const function and trying to assign a value to a member fail with an error message.

src/scripting/thingdef.cpp

@@ -110,12 +110,13 @@ void SetImplicitArgs(TArray<PType *> *args, TArray<DWORD> *argflags, TArray<FNam
 	if (funcflags & VARF_Method)
 	{
 		// implied self pointer
-		if (args != nullptr)		args->Push(NewPointer(cls)); 
+		if (args != nullptr)		args->Push(NewPointer(cls, !!(funcflags & VARF_ReadOnly))); 
 		if (argflags != nullptr)	argflags->Push(VARF_Implicit | VARF_ReadOnly);
 		if (argnames != nullptr)	argnames->Push(NAME_self);
 	}
 	if (funcflags & VARF_Action)
 	{
+		assert(!(funcflags & VARF_ReadOnly));
 		// implied caller and callingstate pointers
 		if (args != nullptr)
 		{

src/scripting/zscript/zcc_compile.cpp

@@ -2156,6 +2156,15 @@ void ZCCCompiler::CompileFunction(ZCC_StructWork *c, ZCC_FuncDeclarator *f, bool
 		}
 		if (f->Flags & ZCC_Action)
 		{
+			if (varflags & VARF_ReadOnly)
+			{
+				Error(f, "Action functions cannot be declared const");
+				varflags &= ~VARF_ReadOnly;
+			}
+			if (varflags & VARF_UI)
+			{
+				Error(f, "Action functions cannot be declared UI");
+			}
 			// Non-Actors cannot have action functions.
 			if (!c->Type()->IsKindOf(RUNTIME_CLASS(PClassActor)))
 			{

wadsrc/static/zscript/actor.txt

@@ -468,15 +468,15 @@ class Actor : Thinker native
 	native bool UpdateWaterLevel (bool splash = true);
 	native bool IsZeroDamage();
 	native void ClearInterpolation();
-	native Vector3 PosRelative(sector sec);
+	native Vector3 PosRelative(sector sec) const;
 		
 	native void HandleSpawnFlags();
 	native void ExplodeMissile(line lin = null, Actor target = null, bool onsky = false);
 	native void RestoreDamage();
-	native int SpawnHealth();
+	native int SpawnHealth() const;
 	native void SetDamage(int dmg);
-	native double Distance2D(Actor other);
+	native double Distance2D(Actor other) const;
-	native double Distance3D(Actor other);
+	native double Distance3D(Actor other) const;
 	native void SetOrigin(vector3 newpos, bool moving);
 	native void SetXYZ(vector3 newpos);
 	native Actor GetPointer(int aaptr);
@@ -511,7 +511,7 @@ class Actor : Thinker native
 	native void BloodSplatter (Vector3 pos, double hitangle, bool axe = false);
 	native bool HitWater (sector sec, Vector3 pos, bool checkabove = false, bool alert = true, bool force = false);
 	native void PlaySpawnSound(Actor missile);
-	native bool CountsAsKill();
+	native bool CountsAsKill() const;
 	
 	native bool Teleport(Vector3 pos, double angle, int flags);
 	native void TraceBleed(int damage, Actor missile);
@@ -559,21 +559,21 @@ class Actor : Thinker native
 	native void LinkToWorld(LinkContext ctx = null);
 	native void UnlinkFromWorld(out LinkContext ctx = null);
 	native bool CanSeek(Actor target);
-	native double AngleTo(Actor target, bool absolute = false);
+	native double AngleTo(Actor target, bool absolute = false) const;
 	native void AddZ(double zadd, bool moving = true);
 	native void SetZ(double z);
-	native vector2 Vec2To(Actor other);
+	native vector2 Vec2To(Actor other) const;
-	native vector3 Vec3To(Actor other);
+	native vector3 Vec3To(Actor other) const;
-	native vector3 Vec3Offset(double x, double y, double z, bool absolute = false);
+	native vector3 Vec3Offset(double x, double y, double z, bool absolute = false) const;
-	native vector3 Vec3Angle(double length, double angle, double z = 0, bool absolute = false);
+	native vector3 Vec3Angle(double length, double angle, double z = 0, bool absolute = false) const;
-	native vector2 Vec2Angle(double length, double angle, bool absolute = false);
+	native vector2 Vec2Angle(double length, double angle, bool absolute = false) const;
-	native vector2 Vec2Offset(double x, double y, bool absolute = false);
+	native vector2 Vec2Offset(double x, double y, bool absolute = false) const;
-	native vector3 Vec2OffsetZ(double x, double y, double atz, bool absolute = false);
+	native vector3 Vec2OffsetZ(double x, double y, double atz, bool absolute = false) const;
-	native void VelFromAngle(double speed = 0, double angle = 0);
+	native void VelFromAngle(double speed = 0, double angle = 0) const;
-	native void Vel3DFromAngle(double speed, double angle, double pitch);
+	native void Vel3DFromAngle(double speed, double angle, double pitch) const;
 	native void Thrust(double speed = 0, double angle = 0);
-	native bool isFriend(Actor other);
+	native bool isFriend(Actor other) const;
-	native bool isHostile(Actor other);
+	native bool isHostile(Actor other) const;
 	native void AdjustFloorClip();
 	native DropItem GetDropItems();
 	native void CopyFriendliness (Actor other, bool changeTarget, bool resetHealth = true);
@@ -588,8 +588,8 @@ class Actor : Thinker native
 	native void Howl();
 	native void DrawSplash (int count, double angle, int kind);
 	native void GiveSecret(bool printmsg = true, bool playsound = true);
-	native double GetCameraHeight();
+	native double GetCameraHeight() const;
-	native double GetGravity();
+	native double GetGravity() const;
 
 	native bool CheckClass(class<Actor> checkclass, int ptr_select = AAPTR_DEFAULT, bool match_superclass = false);
 	native void AddInventory(Inventory inv);
@@ -613,7 +613,7 @@ class Actor : Thinker native
 	native double GetDistance(bool checkz, int ptr = AAPTR_TARGET);
 	native double GetAngle(int flags, int ptr = AAPTR_TARGET);
 	native double GetZAt(double px = 0, double py = 0, double angle = 0, int flags = 0, int pick_pointer = AAPTR_DEFAULT);
-	native int GetSpawnHealth();
+	native int GetSpawnHealth() const;
 	native double GetCrouchFactor(int ptr = AAPTR_PLAYER1);
 	native double GetCVar(string cvar);
 	native int GetPlayerInput(int inputnum, int ptr = AAPTR_DEFAULT);