On 26 March 2011 05:57, Rob Nikander wrote:

I'm trying to use the 'plugins' package.  Since I already posted to stackoverflow I'll just link to that.  I posted a simple program that I thought would work, but mostly doesn't.   Any pointers, appreciated.

http://stackoverflow.com/questions/5427777/help-with-haskell-dynamic-plugin-...

Hi Rob, I don't have a stack overflow account, so I will give a partial answer here. I'm not sure what the issue is with runhaskell, but you are getting a segfault with dynload. The comments on dynload in the source of the plugins package reveal the probable cause: \begin{comment} -- A work-around for Dynamics. The keys used to compare two TypeReps are -- somehow not equal for the same type in hs-plugin's loaded objects. -- Solution: implement our own dynamics... -- -- The problem with dynload is that it requires the plugin to export -- a value that is a Dynamic (in our case a (TypeRep,a) pair). If this -- is not the case, we core dump. Use pdynload if you don't trust the -- user to supply you with a Dynamic \end{comment} So it seems that, to use dynload, you must export a pair containing a typerep and a value, rather than just a value. Plugins also provides pdynload, which is apparently a "super-replacement for dynload", though I didn't look into it in detail. Cheers, Bernie.