The Teal Programming Language

Enums

Enums are a restricted type of string value, which represent a common practice in Lua code: using a limited set of string constants to describe an enumeration of possible values.

You describe an enum like this:

local type Direction = enum
   "north"
   "south"
   "east"
   "west"
end

or like this:

local enum Direction
   "north"
   "south"
   "east"
   "west"
end

Variables and arguments of this type will only accept values from the declared list. Enums are freely convertible to strings, but not the other way around. You can of course promote an arbitrary string to an enum with a cast.