Repel and Go!

local function repel_and_go(command)
  local letter = nil
  local spell = nil
  for l, s in pairs(you.spell_table()) do
    if s == "Deflect Missiles" then
      letter = l
      spell = s
      break
    end
    if spell == "Repel Missiles" then
      letter = l
      spell = s
    end
  end
  if spell and not you.status(spell:lower()) then
    crawl.process_keys("z" .. letter .. command)
  else
    crawl.process_keys(command)
  end
end