grapes can be placed in itemframes

grapes.lua

@@ -1,28 +1,41 @@
 
 local S = farming.intllib
 
--- grapes
-minetest.register_craftitem("farming:grapes", {
-	description = S("Grapes"),
-	inventory_image = "farming_grapes.png",
-	on_use = minetest.item_eat(2),
+-- place trellis
+function place_grapes(itemstack, placer, pointed_thing, plantname)
 
-	on_place = function(itemstack, placer, pointed_thing)
+	local pt = pointed_thing
+
+	-- check if pointing at a node
+	if not pt or pt.type ~= "node" then
 
-		if minetest.is_protected(pointed_thing.under, placer:get_player_name()) then
 		return
 	end
 
-		local nodename = minetest.get_node(pointed_thing.under).name
+	local under = minetest.get_node(pt.under)
 
-		if nodename == "farming:trellis" then
-			minetest.set_node(pointed_thing.under, {name = "farming:grapes_1"})
-
-			minetest.sound_play("default_place_node", {pos = pointed_thing.above, gain = 1.0})
-		else
+	-- return if any of the nodes are not registered
+	if not minetest.registered_nodes[under.name] then
 		return
 	end
 
+	-- am I right-clicking on something that has a custom on_place set?
+	-- thanks to Krock for helping with this issue :)
+	local def = minetest.registered_nodes[under.name]
+	if def and def.on_rightclick then
+		return def.on_rightclick(pt.under, under, placer, itemstack)
+	end
+
+	-- check if pointing at trellis
+	if under.name ~= "farming:trellis" then
+		return
+	end
+
+	-- add the node and remove 1 item from the itemstack
+	minetest.set_node(pt.under, {name = plantname})
+
+	minetest.sound_play("default_place_node", {pos = pt.under, gain = 1.0})
+
 	if not minetest.setting_getbool("creative_mode") then
 
 		itemstack:take_item()
@@ -41,6 +54,16 @@ minetest.register_craftitem("farming:grapes", {
 
 	return itemstack
 end
+
+-- grapes
+minetest.register_craftitem("farming:grapes", {
+	description = S("Grapes"),
+	inventory_image = "farming_grapes.png",
+	on_use = minetest.item_eat(2),
+
+	on_place = function(itemstack, placer, pointed_thing)
+		return place_grapes(itemstack, placer, pointed_thing, "farming:grapes_1")
+	end,
 })
 
 -- grapes can be used for violet dye