Conditional statements

The language supports the traditional IF statement with some optional ELSE and ELSEIF parts.    

  $\vartriangleright$ Syntax:

  IF (condition) THEN
    list of statements
  ELSEIF (condition) THEN
    list of statements
  ELSEIF (...) THEN
    ...
  ELSE
    list of statements
  ENDIF

The condition is not necessary a boolean expression. A condition is considered as true when it is not equal to the constant FALSE. The ELSEIF statement does not exist in some previous versions of TSF.