Debug vs Break

[Martin.Griss <Griss@UTAH-20>]

I'm not entirely familiar with LispM debug vs Break. In PSL, the Break loop
IS a read-eval-print loop; it has a distinguished prompt, and a few
characters/ids are enabled as aliases for functions. E.g.,

Q -> (BREAK-QUIT)
T -> (BREAK-BACK-TRACE)
C -> (BREAK-CONTINUE)
R -> (BREAK-RETRY)

etc. We could envision that the single stepper is also present, and
off, but ready to be invoked in a retry mode, by say S, or some such.

In an environment that we are developing using a multi-window EMACS
like editor (NMODE), we have experimented with a "pop-up"
window/buffer in which the single chars above are present and ready to
be pointed at and executed (a "menu"). Normal editing and execution of
s-expressions can proceed. The Break/Debug commands can also be bound
to appropriate CNTRL-keys (e.g. LISP-Q, LISP-A), via an appropriate
dispatch table for BREAK-MODE, a modified LISP-MODE.

Various  combinations of these techniques can gracefully merge
a "read-eval-print" break loop, with a Debug loop.

Martin
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