While

While allows you to repeat a loop of instructions as long as a condition is true.

Syntax

While EXPRESSION
INSTRUCTION_LIST
Wend

• INSTRUCTION_LIST is a list of instructions in a script.
• EXPRESSION is a numeric expression that is considered as true if it is not equal to 0.

Examples

  # Example 1 : let's perform a computation with successive approximations
  VARIA=INIT_VALUE
  While abs(func COMPUTE(VARIA)-TARGET)>EXPECTED_PRECISION
    VARIA=func ITERATE(VARIA)
  Wend

  # Example 2 : let's wait until the database is updated or until a limit hour is reached
  TIMEOUT="22:00:00"
  While time$<TIMEOUT
    Sleep 1
    Break func DATABASE_UPDATED=1
 Wend

Description

While allows to perform loops as long as the following occurs:

• A condition is true, that is the numeric expression returns a not null value.
• A Break instruction has not been executed to interrupt the loop.

If the condition is false at the beginning, no iteration is done, and the execution resumes after the Wend.

Associated errors

See also

For, To, Next, Step, Break, Repeat, Until, Wend, If, Then, Else, Elsif, Endif.