[Haskell-cafe] Re: Has anyone looked into adding subtyping...

Jason Dagit dagit at codersbase.com
Mon Jun 4 15:14:13 EDT 2007

On 6/2/07, oleg at pobox.com <oleg at pobox.com> wrote:
> > The last time I tried this code, I reported to haskell-cafe that
> > OOHaskell does not work when compiled as a library (at least under
> > GHC).  For some reason the code that uses OOHaskell had to be compiled
> > along side it.  Is this now fixed?
> It may be, I have to try. It should be mentioned that most of the
> OOHaskell functionality (extensible polymorphic records and variants)
> are actually in HList. Einar Karttunen has ported the latter to GHC
> 6.6 and package under Cabal. I think the version is available on
> Hackage. Anyway, the curious behavior requiring the presence of
> OOHaskell sources seems like a problem with GHC separate
> compilation. Could that be distilled to a small example so that we can
> file a GHC problem report?

The smallest example I was able to construct involved building HList
and OOHaskell and installing them as modules.  This was trivial in
some sense, but I think it did require some modification (maybe the
creation of a cabal file?).  After that I simply tried to compile the
examples provided using the libraries I had built.  For some reason
when I did this, the type checker rejected the examples.  Building all
the code together, as it's packaged worked fine.

I have not tried recently.


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