how to use ghci-debugger with packages

[Frederik Eaton]

On Sun, Feb 24, 2008 at 02:36:08AM +0100, Daniel Fischer wrote:
> Am Sonntag, 24. Februar 2008 02:18 schrieb Frederik Eaton:
> > Hello,
> >
> > I have a program which uses some code in a package, and I would like
> > to be able to find out the source of an error which is occuring inside
> > that package. Can I use the ghci-debugger to do this? If I try to set
> > a breakpoint inside the package, it says:
> >
> > "cannot set breakpoint on Vector.Sparse.Wrappers.vmergeOp: module
> > Vector.Sparse.Wrappers is not interpreted"
> >
> > But this page:
> >
> > http://www.haskell.org/ghc/dist/current/docs/users_guide/ghci-debugger.html
> >
> > has no use of the word "package", so I assume that reading that (long)
> > document won't ansnwer my question...
> >
> > Thank you,
> >
> > Frederik
> 
> The users-guide says
> "There is one major restriction: breakpoints and single-stepping are only 
> available in interpreted modules; compiled code is invisible to the 
> debugger."
> 
> The modules of an installed package are always compiled, I think.

That's what I think as well, but I'm not sure (and it seems like the
documentation should mention that: CC'ing glasgow-haskell-bugs). I
can't see a reason why an installed package wouldn't be able to
contain its own source code, for instance...

> If you have the source available, you could try to put that in your working 
> directory (probably hide the installed package before starting ghci).

Thanks, I may try that. I'm currently trying to get my GNU-make-based
build to install profiling versions of package modules, in the hope
that -xc might give more useful information than it did a year ago...

Frederik

-- 
http://ofb.net/~frederik/