use get/set for parameters on ports and wires

sim/group.lua

@@ -24,46 +24,46 @@ function Group.getsize(self)
 end
 
 function Group.addwire(self, wire)
-	if wire.group ~= self then
-		if wire.group ~= nil then
-			self:mergewith(wire.group)
+	if Wire.getgroup(wire) ~= self then
+		if Wire.getgroup(wire) ~= nil then
+			Group.mergewith(self, Wire.getgroup(wire))
 		else
 			self.wires[wire] = wire
 			self.nwires = self.nwires + 1
 			
-			wire.group = self
-			wire:update()
-			sim:queuegroup(self)
+			Wire.setgroup(wire, self)
+			Wire.update(wire)
+			Simulation.queuegroup(sim, self)
 		end
 	end
 end
 
 function Group.removewire(self, wire)
-	wire.group = nil
+	Wire.setgroup(wire, nil)
 	self.wires[wire] = nil
 
 	for k, wire in pairs(self.wires) do
-		wire.group = nil
+		Wire.setgroup(wire, nil)
 	end
 
 	for k, port in pairs(self.out_ports) do
-		port.group = nil
+		Port.setgroup(port, nil)
 	end
 
 	for k, port in pairs(self.in_ports) do
-		port.group = nil
+		Port.setgroup(port, nil)
 	end
 
 	for k, wire in pairs(self.wires) do
-		sim:connectwire(wire)
+		Simulation.connectwire(sim, wire)
 	end
 
 	for k, port in pairs(self.out_ports) do
-		sim:connectport(port)
+		Simulation.connectport(sim, port)
 	end
 
 	for k, port in pairs(self.in_ports) do
-		sim:connectport(port)
+		Simulation.connectport(sim, port)
 	end
 
 	self.wires = {}
@@ -113,7 +113,7 @@ end
 
 function Group.mergeinto(self, group)
 	for k, wire in pairs(self.wires) do
-		wire.group = nil
+		Wire.setgroup(wire, nil)
 		Group.addwire(group, wire)
 	end