[Haskell-cafe] is gldrawingarea an instance of widgetclass

briand at aracnet.com briand at aracnet.com
Wed Dec 24 17:09:02 UTC 2014

On Wed, 24 Dec 2014 11:46:35 +0300
Yuras Shumovich <shumovichy at gmail.com> wrote:

> On Tue, 2014-12-23 at 23:03 -0800, briand at aracnet.com wrote:
> > I get this :
> > 
> >     No instance for (Gtk.WidgetClass GtkGL.GLDrawingArea)
> >       arising from a use of `Gtk.boxPackStart'
> > 
> > in code that was compiling at one point.
> > This is how I'm importing
> > 
> >   import qualified Graphics.UI.Gtk.OpenGL as GtkGL
> Is your code cabalized? If not, then probably you indirectly depend on
> different versions of gtk. For example, GLDrawingArea is instance of
> WidgetClass from one version of gtk, but you need the instance from
> other version of gtk. Check `ghc-pkg list gtk`.

ah. ok.

i bet this is due to the fact that i'm using the debian install of ghc and a locally upgraded cabal.

i've never been able to get the debian ghc and cabal to coexist happily.

i always end up purging it and compiling my own local ghc.

Looks like i'm back to doing that.


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