12.1 General Description

Control statements allow for the interruption of the normal sequence of execution of statements by causing execution to continue at a specified line, rather than at the one with the next higher line number.

The goto-statement

            GO TO line-number
        

allows for an unconditional transfer.

The if-then-statement

            IF expl rel exp2 THEN line-number
        

where "expl" and'texp2" are expressions and "rel" is a relational operator, allows for a conditional transfer.

The gosub and return statements

            GO SUB line-number
            RETURN
        

allow for subroutine calls.

The on-goto-statement

            ON expression GO TO line-number, ..., line-number
        

allows control to be transferred to a selected line.

The stop-statement

            STOP
        

allows for program termination.

12.2 Syntax

            1. goto-statement           = GO space* TO line-number
            2. if-then-statement        = IF relational-expression THEN line-number
            3. relational-expression    = numeric-expression relation numeric-expression /
                                          string-expression equality-relation string-expression
            4. relation                 = equality-relation / less-than-sign / greater-than-sign /
                                          not-less / not-greater
            5. equality-relation        = equals-sign / not-equals
            6. not-less                 = greater-than-sign equals-sign
            7. not-greater              = less-than-sign equals-sign
            8. not-equals               = less-than-sign greater-than-sign
            9. gosub-statement          = GO space* SUB line-number
            10. return-statement        = RETURN
            11. on-goto-statement       = ON numeric-expression GO space* TO line-number (comma line-number)*