[Haskell-cafe] X Haskell Bindings

[Brandon S. Allbery KF8NH]

On 2008 Aug 17, at 20:34, Spencer Janssen wrote:
> On Sat, Aug 16, 2008 at 04:07:25PM -0500, Antoine Latter wrote:
>> Since the request to create a window has so many parameters, these
>> parameters are all wrapped up into a "CreateWindow" data type, which
>> is only ever used by the "createWindow" function.  The "mapWindow"
>> request only has one parameter, so it does not need it's own
>> "MapWindow" data type.
>
> I think this is a nice idea.  This type signature from the X11  
> library is
> absolutely unmanageable:

It's never been manageable, even from C (hence XCreateSimpleWindow()  
in Xlib which defaults most of that).

>    do h <- getHandler c -- save the old handler so we can restore it  
> later
>       setHandler c myHandlingFn
>       performSomeActionsWhichMayFail
>       setHandler c h
>
> Not only is this code ugly, it does not work correctly when the  
> connection may
> be concurrently used by several threads.

or when the async response comes after the handler's been reset (i.e.  
you need to call XSynchronize() and handle any errors before resetting  
the handler).

-- 
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university    KF8NH