how to use ghci-debugger with packages

Daniel Fischer at
Sat Feb 23 20:36:08 EST 2008

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:
> 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 

The modules of an installed package are always compiled, I think.
If you have the source available, you could try to put that in your working 
directory (probably hide the installed package before starting ghci).

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