Re: [Gtk2hs-devel] Allocation data type not exported

[Daniel W. <dm...@dm...>]

Hi Norbert --

These two changes (exporting Allocation + eta-reducing EventM) are now
pushed to the repo. Thanks for the suggestions.

~d

Excerpts from Norbert Zeh's message of 2014-10-30 04:07:42 -0700:
> Thanks.  I just added the export to Widget and manually compiled it here.
> I also changed the type definition of EventM as pointed out in an earlier
> message I sent.  This bug is still present in the current version of
> gtk2hs.  To elaborate: With the current definition of EventM
> 
> type EventM t a = ReaderT (Ptr t) IO a
> 
> it is impossible to use (EventM t) as an argument to a monad transformer,
> e.g.
> 
> type EventMWithState t a = StateT MyState (EventM t) a.
> 
> There are two ways to make this possible.  Either EventM becomes a newtype,
> along with the necessary boilerplate.  That's probably not necessary here.
> The second option is to define
> 
> type EventM t = ReaderT (Ptr t) IO.
> 
> This allows (EventM t) to be combined with monad transformers.
> 
> Cheers,
> Norbert
> 
> On Thu, Oct 30, 2014 at 3:32 AM, Axel Simon <Axe...@in...> wrote:
> 
> > Hi Norbert,
> >
> > On 29.10.2014, at 22:37, Norbert Zeh <nz...@cs...> wrote:
> >
> > > Hi folks,
> > >
> > > I just tried to connect to the sizeAllocate signal of the Widget type,
> > but the type of this signal is Signal self (Allocation -> IO ()).  Thus,
> > the function I provide as an argument needs to take an Allocation as an
> > argument, but I cannot declare a function of this type because Allocation
> > seems to be only exported by the hidden module
> > Graphics.UI.Gtk.General.Structs.  Any advice on how to react to
> > sizeAllocate signals?
> > >
> >
> > Well, it’s a bug, it should be exported from Widget. However, it’s only a
> > type synonym to Rectangle which is public, so using the Rectangle
> > constructor should be possible.
> >
> > Cheers,
> > Axel
> >
> > > Thanks,
> > > Norbert
> > >
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