[Haskell-cafe] Trouble finding exception source
gwern0 at gmail.com
gwern0 at gmail.com
Wed Feb 27 00:06:53 EST 2008
On 2008.02.26 23:13:59 -0500, Denis Bueno <dbueno at gmail.com> scribbled 7.4K characters:
> Hi all,
> I've got some code crashing with "Prelude.foldr1: empty list". In
> GHCi, the code uses too much memory (I kill it after it consumes 1GB)
> to be able to use :trace and :history, but I just found out about the
> -xc RTS option. I tried that, and I get the following:
> <GHC.List.CAF>dsat: Prelude.foldr1: empty list
> Now, manually going through GHC.List
> I only found one CAF, namely prel_list_str, at the bottom of the file.
> However, it is late and I quite possibly missed something. This CAF,
> of course, doesn't seem a likely culprit. I also stumbled on some
> discussion of the explicit call stack
> which exemplifies the behavior I've found, but doesn't seem to suggest
> a way to fix it.
> I'm developing on GHC 6.8.2. I've attached my code, the output of a
> cabal sdist, which requires parse-dimacs  and bitset  (both
> cabalised) to build. If you build the executable (with profiling),
> you should see my behavior by running:
> ./dist/build/dsat/dsat -verify +RTS -xc
> I know that the problem is somewhere in the "Backtracking" section, in
> the backJump function. But I don't know where.
> Any help is appreciated.
Fortuitously, I recently came across a bunch of bioinformatics software in Haskell. One of the libraries was called 'interlude', and it claims to be able to give line locations for errors in the Prelude. I was intending to upload them all as a group once I'd finished, but you might be able to make use of it here.
You can find it here: <http://hackage.haskell.org/cgi-bin/hackage-scripts/package/interlude-0.1.1>.
If it does work out for you, be sure to let me know. I haven't run across any Prelude errors in my code since I installed it, so I haven't really tried it out.
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