Move table.* functions to separate file in mcl_utils, add table.find() and table.intersect()

mods/CORE/mcl_util/init.lua

@@ -3,52 +3,7 @@ mcl_util = {}
 local modname = minetest.get_current_modname()
 local modpath = minetest.get_modpath(modname)
 dofile(modpath.."/roman_numerals.lua")
-
--- Updates all values in t using values from to*.
-function table.update(t, ...)
-	for _, to in ipairs {...} do
-		for k, v in pairs(to) do
-			t[k] = v
-		end
-	end
-	return t
-end
-
--- Updates nil values in t using values from to*.
-function table.update_nil(t, ...)
-	for _, to in ipairs {...} do
-		for k, v in pairs(to) do
-			if t[k] == nil then
-				t[k] = v
-			end
-		end
-	end
-	return t
-end
-
----Works the same as `pairs`, but order returned by keys
----
----Taken from https://www.lua.org/pil/19.3.html
----@generic T: table, K, V, C
----@param t T
----@param f? fun(a: C, b: C):boolean
----@return fun():K, V
-function table.pairs_by_keys(t, f)
-	local a = {}
-	for n in pairs(t) do table.insert(a, n) end
-	table.sort(a, f)
-
-	local i = 0        -- iterator variable
-	local function iter() -- iterator function
-		i = i + 1
-		if a[i] == nil then
-			return nil
-		else
-			return a[i], t[a[i]]
-		end
-	end
-	return iter
-end
+dofile(modpath.."/table.lua")
 
 local LOGGING_ON = minetest.settings:get_bool("mcl_logging_default", false)
 local LOG_MODULE = "[MCL2]"

mods/CORE/mcl_util/table.lua

@@ -0,0 +1,67 @@
+-- Updates all values in t using values from to*.
+function table.update(t, ...)
+	for _, to in ipairs {...} do
+		for k, v in pairs(to) do
+			t[k] = v
+		end
+	end
+	return t
+end
+
+-- Updates nil values in t using values from to*.
+function table.update_nil(t, ...)
+	for _, to in ipairs {...} do
+		for k, v in pairs(to) do
+			if t[k] == nil then
+				t[k] = v
+			end
+		end
+	end
+	return t
+end
+
+---Works the same as `pairs`, but order returned by keys
+---
+---Taken from https://www.lua.org/pil/19.3.html
+---@generic T: table, K, V, C
+---@param t T
+---@param f? fun(a: C, b: C):boolean
+---@return fun():K, V
+function table.pairs_by_keys(t, f)
+	local a = {}
+	for n in pairs(t) do table.insert(a, n) end
+	table.sort(a, f)
+
+	local i = 0        -- iterator variable
+	local function iter() -- iterator function
+		i = i + 1
+		if a[i] == nil then
+			return nil
+		else
+			return a[i], t[a[i]]
+		end
+	end
+	return iter
+end
+
+function table.find(t, item)
+	for k,v in pairs(t) do
+		if v == item then return k end
+	end
+	return nil
+end
+
+function table.intersect(a, b)
+	local values_map = {}
+
+	for _,v in pairs(a) do values_map[v] = 1 end
+	for _,v in pairs(b) do values_map[v] = (values_map[v] or 0) + 1 end
+
+	-- Get all the values that are in both tables
+	local result = {}
+	for v,count in pairs(values_map) do
+		if count == 2 then table.insert(result, v) end
+	end
+	return result
+end
+