This was reported in this thread: https://github.com/lokedhs/gnu-apl-mode/issues/7
This problem seems to be caused by a bug in GNU APL. When the user calls )LOAD to load a workspace, the start_input callback function is not called before control is returned back to the user. (because of this, the Emacs mode just sits there, hung, waiting for a call to start_input that never happens). Regards, Elias
