[slime-devel] Re: OpenMCL

[Luke Gorrie]

Peter Seibel <peter at javamonkey.com> writes:

> Are you planning to make it possible to debug multiple threads
> simultaneously--I.e. it might be nice to set break points in two
> places that will be hit be different threads and then debug them both
> at the same time (in two different debugging buffers); for example
> step a little way in one thread, then switch to the other; etc.

Not initially. Is that something you need?

This is slightly tricky in SLIME because we support a synchronous
evaluation interface in Emacs Lisp. In Elisp you can write:

    (slime-eval '(swank:some-function))

And it will evaluate the form in Lisp and then return the
result. However, it might enter the debugger before it finishes, in
which case Emacs enters a "recursive edit" to do the debugging without
unwinding the Elisp stack (so that when you finish debugging it can
return the final result to the `slime-eval' call). If during debugging
you switched over to another thread and did another `slime-eval'
there, the stack would end up rather tangled -- you have two
`slime-eval's on the stack and have to return to one before the other.

A few possible solutions come to mind, but I think it will be better
to burn this bridge when we come to it and do some
experimentation. Ideas are always welcome, of course.

Cheers,
Luke