os.loadAPI("disk/go")

local function printUsage()
  print("Usage: move <direction> <distance>\n")
  print("Valid directions are")
  print("\tforward, backward, left, right")
  print("\tnorth, south, east, west")
  print("\tup, down\n")
end

local tArgs = { ... }
if #tArgs < 1 then
  printUsage()
  return
end

local sDir = tArgs[1]
local iDis = 1
if #tArgs >= 2 then
  iDis = tArgs[2]
end

if (sDir == "north") or (sDir == "forward") then
  go.north(iDis)
elseif (sDir == "south") or (sDir == "backward") then
  go.south(iDis)
elseif (sDir == "west") or (sDir == "left") then
  go.west(iDis)
elseif(sDir == "east") or (sDir =="right") then
  go.east(iDis)
elseif sDir == "up" then
  go.up(iDis)
elseif sDir == "down" then
  go.down(iDis)
else
  print("Invalid direction.\n")
  printUsage()
end