on shiftLeft howMany
  -- shift the selection left.
  if howMany is empty then put 1 into howMany
  get the selection
  repeat with i = 1 to the number of lines in it
    repeat howMany times
      if char 1 of line i of it is space then delete char 1 of line i of it
    end repeat
  end repeat
  replaceAll it
end shiftLeft