Imperative constructions

 

• The sequence is introduced by the keyword ``do''. Each instruction of the sequence, except the last one, ends with a semicolon. The sequence is terminated by the keyword ``return'' followed by the last intruction:

  Ocaml	Righteous
  e1; e2; e3; e4	do e1; e2; e3; return e4

• In the body of ``for'' and ``while'' loops, all instructions end with a semicolon, the last one included:

  Ocaml	Righteous
  while e1 do	while e1 do
  e2; e3; e4	e2; e3; e4;
  done	done

• It is possible to write an empty sequence, equivalent to the last expression alone, a ``while'' loop and a ``for'' loop with an empty body, equivalent to a loop where the body is ``()'':

      do return e
      while e do done
      for i = e1 to e2 do done