Debugging Emacs with gdba

[Nick Roberts <nickrob@snap.net.nz>]

If you debug Emacs from within Emacs, read on:

I've modified gud-pp to work from the speedbar.  So if you watch a structure
e.g a window, you can place the cursor over one of the components, press
p and display its lisp value in the GUD buffer:

Speedbar:

Watch Expressions:
o	struct window *
 size	1073745994
 vec_next	struct Lisp_Vector *
 frame	140441948
 mini_p	137829369
 next	153394732
 prev	137829369
 hchild	137829369
 vchild	137829369
 parent	137829369
 ...

GUD buffer:

(gdb)
o.next = #<window 4 on  *Minibuf-0*>
(gdb)

It won't work from the tool-bar because that frame takes focus and changes
point to the value in the newly selected window.

Currently it only works on lisp objects which are components of a structure
but I could get it to work on arrays of lisp objects, if they exist in Emacs.

When the cursor is over a value in the speedbar, the tooltip now displays the
data type.  Unfortunately for lisp objects it displays "int".  It would be
nice if it displayed Lisp_Object.  I don't know how to get it to do this,
though.

Nick