Introduce utility function for deriving table fields

machines/solar_panel_generator.lua

@@ -15,8 +15,7 @@
 -- along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 local S=minetest.get_translator("industrialtest")
-industrialtest.SolarPanelBase=table.copy(industrialtest.ElectricMachine)
-industrialtest.internal.unpackTableInto(industrialtest.SolarPanelBase,{
+industrialtest.SolarPanelBase=industrialtest.internal.derive(industrialtest.ElectricMachine,{
 	sounds="metal",
 	requiresWrench=true,
 	storageLists={
@@ -78,8 +77,7 @@ function industrialtest.SolarPanelBase.action(self,pos)
 	end
 end
 
-industrialtest.SolarPanel=table.copy(industrialtest.SolarPanelBase)
-industrialtest.internal.unpackTableInto(industrialtest.SolarPanel,{
+industrialtest.SolarPanel=industrialtest.internal.derive(industrialtest.SolarPanelBase,{
 	name="industrialtest:solar_panel",
 	description=S("Solar Panel"),
 	tiles={
@@ -106,8 +104,7 @@ minetest.register_craft({
 	}
 })
 
-industrialtest.LVSolarArray=table.copy(industrialtest.SolarPanelBase)
-industrialtest.internal.unpackTableInto(industrialtest.LVSolarArray,{
+industrialtest.LVSolarArray=industrialtest.internal.derive(industrialtest.SolarPanelBase,{
 	name="industrialtest:lv_solar_array",
 	description=S("LV Solar Array"),
 	tiles={
@@ -135,8 +132,7 @@ minetest.register_craft({
 	}
 })
 
-industrialtest.MVSolarArray=table.copy(industrialtest.SolarPanelBase)
-industrialtest.internal.unpackTableInto(industrialtest.MVSolarArray,{
+industrialtest.MVSolarArray=industrialtest.internal.derive(industrialtest.SolarPanelBase,{
 	name="industrialtest:mv_solar_array",
 	description=S("MV Solar Array"),
 	tiles={
@@ -164,8 +160,7 @@ minetest.register_craft({
 })
 
 
-industrialtest.HVSolarArray=table.copy(industrialtest.SolarPanelBase)
-industrialtest.internal.unpackTableInto(industrialtest.HVSolarArray,{
+industrialtest.HVSolarArray=industrialtest.internal.derive(industrialtest.SolarPanelBase,{
 	name="industrialtest:hv_solar_array",
 	description=S("HV Solar Array"),
 	tiles={