Consider this: (defun foo () (break)) (foo) This nicely brings up sldb. Press B to get to the lisp debugger repl. Then enter "(si <tab>" to try to complete this. This basically hangs with a pipelined request message. Can't do anything but press C-g to break out of this. I think this used to work long ago, but I'm not sure anymore. It was rather nice to have the debugger repl work just like the normal repl. Ray