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Flow Overrides |
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Sometimes, it is necessary to exit a running loop (sub-routine, procedure) as soon as a specific task is completed, regardless of the value of the control variable or test expression.
The following directives allow for immediate termination of a loop or sub-routine:
The BREAK directive terminates an active loop and transfers control to the statement immediately after where the loop normally ends; i.e. NEXT or WEND.
Example:
0010 DIM X$[100](1,"*"); LET X$[50]=""
0020 FOR I=1 TO 100
0030 IF X$[I]="" THEN BREAK
0040 NEXT
0050 ESCAPE
If the conditional BREAK is executed, the program skips to line 0050.
For syntax details, see BREAK directive.
The EXITTO directive terminates the currently active loop or sub-routine and transfers control to the statement reference indicated.
Example:
0010 DIM X$[100](1,"*"); LET X$[50]=""
0020 FOR I=1 TO 100
0030 IF X$[I]="" THEN EXITTO 50
0040 NEXT
0050 ESCAPE
For syntax details, see EXITTO directive.
Use this directive to clear (pop) the top entry from the FOR..NEXT, WHILE..WEND, REPEAT..UNTIL, GOSUB stack. POP is equivalent to EXITTO except that it does not transfer control (to a statement reference) but continues with the next statement in direct execution sequence.
For syntax details, see POP directive.
The CONTINUE directive is similar to the BREAK directive in that it causes the current iteration of a loop to be terminated, but unlike BREAK, it resumes the loop's execution with the next natural cycle.
Example:
0010 DIM X$[100](1,"*"); LET X$[50]="",K$="*"
0020 FOR I=1 TO 100
0030 IF X$[I]=K$ THEN CONTINUE
0040 PRINT I
0050 NEXT
0060 ESCAPE
For syntax details, see CONTINUE directive.