Directions for turtlebot within minecraft.

Direction.lua

-- Directions
local Direction = {}
Direction.left = "left"
Direction.right = "right"
Direction.forward = "forward"
Direction.back = "back"
Direction.up = "up"
Direction.down = "down"
Direction.isValid = function(direction)
  local dir = string.lower(direction)
  return dir == Direction.left or
         dir == Direction.right or
         dir == Direction.forward or
         dir == Direction.back or
         dir == Direction.up or
         dir == Direction.down
end
Direction.new = function(initial)
  local self = {
    current = Direction.left
  }
  if Direction.isValid(initial) then
     self.current = initial
  end

  function self.opposite()
    switch = {
      [Direction.left] = function() return Direction.right end,
      [Direction.right]= function() return Direction.left end,
      [Direction.up]= function() return Direction.down end,
      [Direction.down]= function() return Direction.up end,
      [Direction.forward]= function() return Direction.back end,
      [Direction.back]= function() return Direction.forward end,
    }
    return switch[self.current]()
  end

  return self
end
t = Direction.new("left")
print(t.current)
print(t.opposite())
t = Direction.new("up")
print(t.current)
print(t.opposite())
t = Direction.new("forward")
print(t.current)
print(t.opposite())