Re: Problems with debug-on-entry in the Lisp debugger.

[Richard Stallman]

    Below is a quick "proof-of-concept" patch for src/eval.c and
    lisp/emacs-lisp/debug.el to get a better idea of what I mean.  As you
    can see, the change to eval.c isn't that big.

The code is not unclean, but I don't think it is a real problem 
that the debug-on-entry code is visible.  So I'd rather not
go in this direction.

This is not the part of Emacs that is important to improve.
Hackers tend to focus their attention on the parts of Emacs
that make it seem more elegant in programmers' terms,
but this doesn't make Emacs more powerful or a better editor.

Could you possibly look at implementing something listed in etc/TODO?