JBreak: forcing J to stop executing the current process
JBreak is a separate program (i.e. application), distinct from the J IDE itself.
- In Windows it is a desktop or Start menu item with the "yellow J" icon.
- On the Apple Macintosh it is an "app" with the "yellow J" icon. Its usual position is in "Dock".
If you click this item when J is running, it causes J to signal an attention interrupt error.
Technically this is a J error, but logically it is not a mistake since it can only arise via deliberate action by the user.
If J appears to "freeze" (e.g. by executing a very long loop) this provides you a way to force J to stop what it is doing and issue a prompt for new input.