WHILE (BEXP) statement ...
  -or-
WHILE (BEXP) DO
 statement(s)
ENDWHILE

 Function
  Execute one or more statments while a condition is true.

 Syntax
  WHILE (BEXP) statement
  -or-
  WHILE (BEXP) DO
    statement(s)
  ENDWHILE

   BEXP       - Any boolean expression.
   statement  - Any valid PPL statement.

 Remarks
  Computers are known for their ability to perform monotonous tasks
  quickly, efficiently, and accurately.  What better way to implement
  monotony than through a WHILE loop?  The WHILE statement supports two
  types of loops:  logical and block.  A logical WHILE loop is a single
  statement; if a condition is TRUE, execute a single statement and check
  again.  A block WHILE loop can be one or more statements.  The start of a
  block WHILE loop is differentiated from a logical WHILE loop by the DO
  keyword immediately after the condition.  At some point in the loop some
  action must be taken that will make the condition FALSE.  If the
  condition never changes from TRUE to FALSE you have what is known as an
  infinite loop; your computer will appear to be hung, even though it is
  rapidly executing things just as fast as it can.  Be sure to thoroughly
  test all programs, but especially programs with loops!

 Examples
  INTEGER i
  LET i = 0
  WHILE (i < 10) GOSUB sub
  END
  :sub
  PRINTLN "i is ",i
  INC i
  RETURN

  INTEGER i
  LET i = 0
  WHILE (i < 10) DO
   PRINTLN "i is ",i
   INC i
  ENDWHILE