functions: add function to copy tables

env/functions.lua

@@ -35,3 +35,21 @@ function CreateGoldString(money)
 
   return string
 end
+
+function CopyTable(src)
+  local lookup_table = {}
+  local function _copy(src)
+    if type(src) ~= "table" then
+      return src
+    elseif lookup_table[src] then
+      return lookup_table[src]
+    end
+    local new_table = {}
+    lookup_table[src] = new_table
+    for index, value in pairs(src) do
+      new_table[_copy(index)] = _copy(value)
+    end
+    return setmetatable(new_table, getmetatable(src))
+  end
+  return _copy(src)
+end