Program Control

Although execution of a procedure generally proceeds from top to bottom, procedure control statements enable you to channel a procedure's execution to different sections, to subroutines, or to the debugger. Program control statements can also halt execution of a procedure.

Statement	Description
Call statement	Branches to an external subroutine.
Case statement	Provides a framework for conditional branching. Evaluates one or more test expressions, then executes the relevant code at the corresponding internal subroutine label. A Case statement must be introduced with Begin Case and terminated with End Case.
Debug statement	Invokes the debugger.
End statement	Terminates a Then or Else condition.
Function()	Similar to the "call @" syntax for subroutines, the Function syntax allows a function to be called whose name is indeterminate at compile time.
GoSub statement	Branches to an internal subroutine.
GoTo statement	Branches unconditionally to another portion of the procedure.
If condition expression	Same as single line If statement, except that the entire statement is evaluated as an expression, leaving only one of two values.
If...Then statement	Performs single-line or multiple-line logic. If not single-line, statements for both branches must be delimited with End. Multi-line conditional logic syntax is applicable to all conditional statements (such as Read or Locate statements).
Loop statement	Marks the beginning of a group of statements, where the group is to be executed repeatedly, until the test expression is satisfied.
Null statement	Used if a statement is called for, but no action is desired (example: If … Then Null Else …).
On...GoSub statement	Branches to local subroutines. When the subroutine is terminated, control returns to the statement following this one.
On...GoTo statement	Branches to one of several statement labels.
Return statement	Branches back to the statement following the calling statement. If used from a function, Return can pass a value back to the calling stored procedure or event handler.