[CM] snd & inf-snd.el: multiple lines

[Bill Schottstaedt]

> Hmmm, it would be nice to have a way to interrupt a currently running 
> calculation from emacs (or sound playback). "ctrl-g" does not seem to 
> have the same effect that it has in snd. And a double "ctrl-c" in the 
> scheme buffer causes the interpreter to quit. 

To interrupt the s7 evaluator, you need to set up the s7 begin_hook
to watch for some signal from emacs (I don't know how this works),
then return true so that s7 internally calls s7_quit, which on a good
day will return s7 to a clean state awaiting the next expression.
To interrupt playback requires that the begin_hook and the no-gui
playback process cooperate as in C-g in the gui case.  It seems
easier to have the gui, but just ignore it -- you can set :to-snd to
#f in with-sound to turn off the automatic display (or *to-snd* to
change the default).