+function core.pos_to_string(pos, decimal_places)
+ local x = pos.x
+ local y = pos.y
+ local z = pos.z
+ if decimal_places ~= nil then
+ x = string.format("%." .. decimal_places .. "f", x)
+ y = string.format("%." .. decimal_places .. "f", y)
+ z = string.format("%." .. decimal_places .. "f", z)
+ end
+ return "(" .. x .. "," .. y .. "," .. z .. ")"
+end
+
+--------------------------------------------------------------------------------
+function core.string_to_pos(value)
+ if value == nil then
+ return nil
+ end
+
+ local p = {}
+ p.x, p.y, p.z = string.match(value, "^([%d.-]+)[, ] *([%d.-]+)[, ] *([%d.-]+)$")
+ if p.x and p.y and p.z then
+ p.x = tonumber(p.x)
+ p.y = tonumber(p.y)
+ p.z = tonumber(p.z)
+ return p
+ end
+ local p = {}
+ p.x, p.y, p.z = string.match(value, "^%( *([%d.-]+)[, ] *([%d.-]+)[, ] *([%d.-]+) *%)$")
+ if p.x and p.y and p.z then
+ p.x = tonumber(p.x)
+ p.y = tonumber(p.y)
+ p.z = tonumber(p.z)
+ return p
+ end
+ return nil
+end
+
+assert(core.string_to_pos("10.0, 5, -2").x == 10)
+assert(core.string_to_pos("( 10.0, 5, -2)").z == -2)
+assert(core.string_to_pos("asd, 5, -2)") == nil)
+
+--------------------------------------------------------------------------------
+function table.copy(t, seen)
+ local n = {}
+ seen = seen or {}
+ seen[t] = n
+ for k, v in pairs(t) do
+ n[type(k) ~= "table" and k or seen[k] or table.copy(k, seen)] =
+ type(v) ~= "table" and v or seen[v] or table.copy(v, seen)
+ end
+ return n