*Conan The Librarian
1.$ COUNT = 0 $ LOOP: $ COUNT = COUNT + 1 . . . $ IF COUNT .LE. 10 THEN GOTO LOOP $ EXIT This example shows how to establish a loop in a command procedure, using a symbol named COUNT and an IF statement. The IF statement checks the value of COUNT and performs an EXIT command when the value of COUNT is greater than 10. 2.$ IF P1 .EQS. "" THEN GOTO DEFAULT $ IF (P1 .EQS. "A") .OR. (P1 .EQS. "B") THEN GOTO 'P1' $ WRITE SYS$OUTPUT "Unrecognized parameter option ''P1' " $ EXIT $ A: ! Process option a . . . $ EXIT $ B: ! Process option b . . . $ EXIT $ DEFAULT: ! Default processing . . . $ EXIT This example shows a command procedure that tests whether a parameter was passed. The GOTO command passes control to the label specified as the parameter. If the procedure is executed with a parameter, the procedure uses that parameter to determine the label to branch to. For example: @TESTCOM A When the procedure executes, it determines that P1 is not null, and branches to the label A. Note that the EXIT command causes an exit from the procedure before the label B. 3.$ SET NOON . . . $ LINK CYGNUS,DRACO,SERVICE/LIBRARY $ IF $STATUS $ THEN $ RUN CYGNUS $ ELSE $ WRITE SYS$OUTPUT "LINK FAILED" $ ENDIF $ EXIT This command procedure uses the SET NOON command to disable error checking by the command procedure. After the LINK command, the IF command tests the value of the reserved global symbol $STATUS. If the value of $STATUS indicates that the LINK command succeeded, then the program CYGNUS is run. If the LINK command returns an error status value, the command procedure issues a message and exits.