Add Digtron compatibility

Override digtron's item-place function to be able to place tracks with digtrons.

advtrains/advtrains/depends.txt

@@ -1,2 +1,3 @@
 default
-mesecons?
+mesecons?
+digtron?

advtrains/advtrains/digtron.lua

@@ -0,0 +1,25 @@
+--digtron.lua
+--make tracks placeable by digtrons by overriding the place function.
+
+local old_item_place = digtron.item_place_node
+
+digtron.item_place_node = function(itemstack, placer, place_to, param2)
+	if minetest.get_item_group(itemstack:get_name(), "advtrains_trackplacer")>0 then
+		return advtrains.pcall(function()
+			local def = minetest.registered_items[itemstack:get_name()]
+			if not def then return itemstack, false end
+			
+			local pointed_thing = {}
+			pointed_thing.type = "node"
+			pointed_thing.above = {x=place_to.x, y=place_to.y, z=place_to.z}
+			pointed_thing.under = {x=place_to.x, y=place_to.y - 1, z=place_to.z}
+			
+			--call the on_rightclick callback
+			local success
+			itemstack, success = def.on_place(itemstack, placer, pointed_thing)
+			return itemstack, success
+		end)
+	else
+		return old_item_place(itemstack, placer, place_to, param2)
+	end
+end

advtrains/advtrains/init.lua

@@ -121,6 +121,9 @@ dofile(advtrains.modpath.."/misc_nodes.lua")
 dofile(advtrains.modpath.."/crafting.lua")
 dofile(advtrains.modpath.."/craft_items.lua")
 
+if digtron then
+	dofile(advtrains.modpath.."/digtron.lua")
+end
 
 --load/save
 

advtrains/advtrains/trackplacer.lua

@@ -185,19 +185,19 @@ function tp.register_track_placer(nnprefix, imgprefix, dispname)
 		description = dispname,
 		inventory_image = imgprefix.."_placer.png",
 		wield_image = imgprefix.."_placer.png",
-		groups={},
+		groups={advtrains_trackplacer=1},
 		on_place = function(itemstack, placer, pointed_thing)
 			return advtrains.pcall(function()
 					local name = placer:get_player_name()
 				if not name then
-				   return itemstack
+				   return itemstack, false
 				end
 				if pointed_thing.type=="node" then
 					local pos=pointed_thing.above
 					local upos=vector.subtract(pointed_thing.above, {x=0, y=1, z=0})
 					if advtrains.is_protected(pos,name) then
 						minetest.record_protection_violation(pos, name)
-						return itemstack
+						return itemstack, false
 					end
 					if minetest.registered_nodes[minetest.get_node(pos).name] and minetest.registered_nodes[minetest.get_node(pos).name].buildable_to
 						and minetest.registered_nodes[minetest.get_node(upos).name] and minetest.registered_nodes[minetest.get_node(upos).name].walkable then
@@ -207,7 +207,7 @@ function tp.register_track_placer(nnprefix, imgprefix, dispname)
 						end
 					end
 				end
-				return itemstack
+				return itemstack, true
 			end)
 		end,
 	})