Debugging Guile with gdb

[Maciej Stachowiak <mstachow@mit.edu>]

I just discovered that running the Scheme version of the scwm doc
extractor under the current version of Guile coredumps at line 274 of
string.c. This is in the middle of string-ref, and the object it
thinks is a string turns into a bad pointer.

I am having a hard time tracking this bug further because to examine
SCM values it is necessary to unwrap many layers of complex macros to
be able to pass something useful to gdb's `print' command. I noticed
that Guile has some files in it to provide a gdb interface. Will that
help me in any way? And if so, how do I use it?

I'd really like to track this bug down, obviously this is something
that should be fixed before the Guile release if possible, since it's
bad for user code to crash the interpreter, but I'd feel bad
submitting the whole huge doc extractor as a minimal failing case. As
such I'd like to examine what's going on further and figure out what
created the object that looks like a string and even has what looks
like a string length, but has no valid character pointer.

 - Maciej