On Sat, 2007-12-08 at 13:08 -0800, Stefan O'Rear wrote:
On Sat, Dec 08, 2007 at 08:33:36PM +0000, Andrew Coppin wrote:
I just spent the evening writing a library that's a thin layer over Gtk2hs. It took an age to get it to compile, but eventually it worked. Yay!
When I ran it, I got this:
Test2: gtk/Graphics/UI/Gtk/Gdk/PixbufData.hs.pp:58:0: No instance nor default method for class operation Data.Array.Base.getNumElements
Er... wow.
OK, at this point, I am completely stumped. Any hints?
That's pretty obviously a bug - Graphics.UI.Gtk.Gdk.PixbufData doesn't fully implement the (M)Array class.
The MArray class changed in ghc-6.8 and we didn't notice until the gtk2hs release was already out. So there are a couple workarounds, either grab the darcs version of the 0.9.12 branch which contains the fix: http://darcs.haskell.org/gtk2hs-branches/gtk2hs-0.9.12/ Or use the released version with ghc-6.6.x rather than 6.8.x, since 6.6 has the previous different MArray interface. Or use the unsafe indexing operators which bypass the bounds check which calls getNumElements. Duncan