WHILE statement

Syntax

WHILE condition DO [cfl_statement] [...] END [WHILE] ;

Components
condition	A Boolean expression containing CCL operators, variables defined within the CCL function definition, and/or parameters defined in the Create Function Statement.
cfl_statement	A CFL statement. See CCL Function Language Overview and Create Function Statement for more information.

Usage

The CFL While statement creates a loop which executes the CFL statements contained in the DO clause, as long as the specified condition remains true.

The condition is evaluated before the loop is executed for the first time, and then every time the loop is about to be repeated. Since the condition is evaluated before the first execution, it is possible that the statement block will not be executed at all (if the condition is false on the initial evaluation).

DANGER

You can create a While statement that never exits (an"endless loop). Always avoid this situation by making sure that the loop contains sufficient logic so that the condition will ultimately evaluate as false.

CFL includes two simple statements that can only be used inside the DO clause of a While statement: the Break statement, which forces an immediate exit from the loop, and the Continue statement, which interrupts the execution of the loop and forces an immediate re-evaluation of the WHILE condition.

Examples

Here is an illustration of a While statement:

CREATE FUNCTION Pow(Value FLOAT, Power INTEGER)
RETURNS FLOAT
   CREATE VARIABLE FLOAT Result =1;
   IF (Power < 0) THEN
      Power = -Power;
      Value = 1/Value
   END IF;
   WHILE 0 < Power DO
      Result = Result * Value
      Power = Power -1;
   END WHILE;
   RETURN Result;
END FUNCTION;

WHILE statement

Syntax

Usage

See Also

Examples