Add code to support raillike group names

builtin/game/misc.lua

@@ -112,3 +112,14 @@ function core.record_protection_violation(pos, name)
 	end
 end
 
+local raillike_ids = {}
+local raillike_cur_id = 0
+function core.raillike_group(name)
+	local id = raillike_ids[name]
+	if not id then
+		raillike_cur_id = raillike_cur_id + 1
+		raillike_ids[name] = raillike_cur_id
+		id = raillike_cur_id
+	end
+	return id
+end

doc/lua_api.txt

@@ -2190,6 +2190,10 @@ These functions return the leftover itemstack.
     * Get rating of a group of an item. (`0` means: not in group)
 * `minetest.get_node_group(name, group)`: returns a rating
     * Deprecated: An alias for the former.
+* `minetest.raillike_group(name)`: returns a rating
+    * Returns rating of the connect_to_raillike group corresponding to name
+    * If name is not yet the name of a connect_to_raillike group, a new group id
+    * is created, with that name
 * `minetest.get_content_id(name)`: returns an integer
     * Gets the internal content ID of `name`
 * `minetest.get_name_from_content_id(content_id)`: returns a string