User control: the STOP symbol

User interaction in the Pipeline is controlled by the STOP symbol. In non-interactive mode, this symbol is automatically defined as equivalent to command CONTINUE, so that the pipeline proceeds unattended. In Widget mode, it is defined as command PAUSE, so that the user can look at the result before proceeding.

This default behaviour can be modified at will if the user pre-defines symbol STOP before using the PIPELINE command. It can also be changed by using the STOP? menu in the main Widget bar.