RAISE EXCEPTION to exit nested code

The following figure shows how you can use the RAISE EXCEPTION statement to break out of a deeply nested block.

Figure 1: The RAISE EXCEPTION statement.

BEGIN
  ON EXCEPTION IN (1)
  END EXCEPTION WITH RESUME -- do nothing significant (cont)

  BEGIN
    FOR i IN (1 TO 1000)
      FOREACH select ..INTO aa FROM t
        IF aa < 0 THEN
          RAISE EXCEPTION 1;     -- emergency exit
        END IF
      END FOREACH
    END FOR
    RETURN 1;
  END 
  
  --do something;               -- emergency exit to
                                -- this statement.
  TRACE 'Negative value returned';
  RETURN -10;
END

If the innermost condition is true (if aa is negative), then the exception is raised and execution jumps to the code following the END of the block. In this case, execution jumps to the TRACE statement.

Remember that a BEGINEND block is a single statement. If an error occurs somewhere inside a block and the trap is outside the block, the rest of the block is skipped when execution resumes, and execution begins at the next statement.

Unless you set a trap for this error somewhere in the block, the error condition is passed back to the block that contains the call and back to any blocks that contain the block. If no ON EXCEPTION statement exists that is set to handle the error, execution of the SPL routine stops, creating an error for the routine that is executing the SPL routine.