Loop statements

While

The While loop allows you to execute a block of statements repeatedly while a boolean expression evaluates to true.

Note that a While loop may never actually execute any of it's statements if the expression evaluates to false when the loop is entered.

The syntax for the While loop is:

While Expression

    Statements...

Wend

End or End While may be used instead of Wend.

Exit and Continue may be used within a While loop to abruptly terminate or continue loop execution.

Repeat..Until / Forever

Like the While loop, the Repeat loop also allows you to execute a block of statement repeatedly while a boolean expression evaluates to true.

However, unlike a While loop, a Repeat loop is guaranteed to execute at least once, as the boolean expression is not evaluated until the end of the loop.

The syntax for Repeat/Until loops is:

Repeat

    Statements...

Until Expression

..or..

Repeat

    Statements...

Forever

Exit and Continue may be used within a Repeat loop to abruptly terminate or continue loop execution.

For..To

A numeric For loop will continue executing until the value of a numeric index variable reaches an exit value.

The index variable is automatically updated every loop iteration by adding a constant step value.

The syntax for a numeric For loop is:

For [ Local ] IndexVariable [:]= FirstValue To | Until LastValue [ Step StepValue ]

    Statements...

Next

End or End For may be used instead of Next.

If present, Local will create a new local index variable that only exists for the duration of the loop. In addition, IndexVariable must include the variable type, or := must be used instead of = to implicitly set the variable's type.

If Local is not present, IndexVariable must be a valid, existing variable.

The use of To or Until determines whether LastValue should be inclusive or exclusive.

If To is used, the loop will exit once the index variable is greater than LastValue (or less than if StepValue is negative).

If Until is used, the loop will exit once the index variable is greater than or equal to LastValue (or less than or equal to if StepValue is negative).

If omitted, StepValue defaults to 1.

Exit and Continue may be used within a numeric For loop to abruptly terminate or continue loop execution.

For..Eachin

A For..EachIn loop allows you to iterate through the elements of a collection.

A collection is either an array, a string, or a specially designed object.

The syntax for a **For..EachIn loop is:

For [ Local ] IndexVariable [:]= EachIn Collection

    Statements...

Next

End or End For may be used instead of Next.

If present, Local will create a new local index variable that only exists for the duration of the loop. In addition, IndexVariable must include the variable type, or := must be used instead of = to implicitly set the variable's type.

If Local is not present, IndexVariable must be a valid, existing variable.

If Collection is an array, the loop will iterate through each element of the array, and the type of the index variable must match the element type of the array.

If Collection is a string, the loop will iterate through each character code of the string, and the type of the index variable must be numeric.

If Collection is an object, it must implement the std.collections.IContainer interface.

Exit

Exit can be used within While, Repeat and For loops to abruptly exit the loop before the loop termination condition has been met.

Continue

Continue can be used within While, Repeat and For loops to force the loop to abruptly skip to the next loop iteration, skipping over any statements that may be remaining in the current loop iteration.