ComputerCraft Tutorial: key_test0_1

-- ###########################
-- key_test
-- version 0.1
-- http://hevohevo.hatenablog.com/

-- ###########################
-- functions
function moveSymbol(x,y)
  term.setCursorPos(x,y)
  term.write("@")
  term.setCursorPos(x,y)
end

function moveSymbol2(x,y)
  term.write(" ")
  term.setCursorPos(x,y)
  term.write("@")
  term.setCursorPos(x,y)
end

-- ###########################
-- main
MAX_X, MAX_Y = term.getSize()

term.clear()
moveSymbol(1,1)

while true do
  local ename, keycode = os.pullEvent("key")

  if ename == "key" then
    local x, y = term.getCursorPos()

    if keycode == keys.up and y > 1 then
      moveSymbol(x,y-1)
    elseif keycode == keys.down and y < MAX_Y then
      moveSymbol(x,y+1)
    elseif keycode == keys.left and x > 1 then
      moveSymbol(x-1,y)
    elseif keycode == keys.right and x < MAX_X then
      moveSymbol(x+1,y)
    elseif keycode == keys.q then
      break -- terminated
    else
      -- do nothing
    end
  end

  sleep(0)
end