add recipes for converting between pipeworks injector variants

fixes pandorabox-io/pandorabox.io#622

recipes.lua

@@ -187,3 +187,40 @@ if minetest.get_modpath("farming") and minetest.get_modpath("moreores") then
 		}
 	})
 end
+
+-- Recipes for converting between pipeworks injector variants
+-- https://github.com/pandorabox-io/pandorabox.io/issues/622
+if minetest.get_modpath("pipeworks") then
+	minetest.register_craft({
+		output = "pipeworks:filter",
+		recipe = {{"pipeworks:mese_filter", "default:mese_crystal"}},
+		replacements = {{"pipeworks:mese_filter", "default:mese"}}
+	})
+	minetest.register_craft({
+		output = "pipeworks:mese_filter",
+		recipe = {{"pipeworks:filter", "default:mese"}},
+		replacements = {{"pipeworks:filter", "default:mese_crystal"}}
+	})
+	if minetest.get_modpath("digilines") then
+		minetest.register_craft({
+			output = "pipeworks:digiline_filter",
+			recipe = {{"pipeworks:mese_filter", "digilines:wire_std_00000000"}},
+			replacements = {{"pipeworks:mese_filter", "default:mese"}}
+		})
+		minetest.register_craft({
+			output = "pipeworks:digiline_filter",
+			recipe = {{"pipeworks:filter", "digilines:wire_std_00000000"}},
+			replacements = {{"pipeworks:filter", "default:mese_crystal"}}
+		})
+		minetest.register_craft({
+			output = "pipeworks:filter",
+			recipe = {{"pipeworks:digiline_filter", "default:mese_crystal"}},
+			replacements = {{"pipeworks:digiline_filter", "digilines:wire_std_00000000"}}
+		})
+		minetest.register_craft({
+			output = "pipeworks:mese_filter",
+			recipe = {{"pipeworks:digiline_filter", "default:mese"}},
+			replacements = {{"pipeworks:digiline_filter", "digilines:wire_std_00000000"}}
+		})
+	end
+end