[web-devel] Rich Internet Applications using Haskell

Bardur Arantsson spam at scientician.net
Thu Feb 10 08:36:20 CET 2011

On 2011-02-10 08:12, Bardur Arantsson wrote:
 > Immediate plans:

Oh, and I forgot:

Widget composability. I'm not really sure how best to proceed with this 
and whether it's really necessary. The current "workaround" is to have 
ordinary Haskell functions (running in the CallbackM monad) which take a 
set of event handlers as callbacks and which return a container widget. 
Something like:

mkMyLastNameFormWidget :: CallbackM -> CallbackM Panel
mkMyLastNameFormWidget onChange = do
   p <- mkPanel
   label <- mkLabel "Last name:"
   input <- mkInput
   addToPanel p label
   addToPanel p input
   return p

Getting at the "composed" state is not trivial, though. Currently that 
would require mkMyLastNameFormWidget to also return the "input" widget 
which would break encapsulation.


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