Hi Erik,

there seem to be several options. Tie simplest one is that you'll call getEvent with some reasonable timeout in a loop and check some communication channel an update from the calculation thread.

Probably the correct way how to handle it involves three threads:

(1) The computation thread writes its updates to a channel of type Either Event ComputationUpdate using Right.

(2) Another thread calls getEvent repeatedly and writes received events to the channel using Left.

(3) A consuming thread (the one for Ncurses UI) consumes the channel and reacts both to computation updates and Ncurses events.

However, I'm not sure if Ncurses doesn't mind calling getEvent from a different thread than the one that updates UI.

For the communication channel, I'd probably use TQueue (or TBQueue, if there is a risk of writing values too fast).

Best regards,

Petr Pudlak

2013/1/26 Erik de Castro Lopo <mle+hs@mega-nerd.com>

Hi all,

I am in the process of writing a Haskell program consisting of two
threads, one for performing a calculation and one for an Ncurses UI
(haskell-ncurses).

The calculation thread needs to feed a stream of numbers back to the
UI thread (about 1 value per second) and the UI needs to take input
from the user and will pass parameter changes to the calculation
thread using an IORef and atomicModifyIORef.

However, I'm not sure how to hande the UI thread. The UI thread would
normally wait for Ncurses input using getEvent, but I need advice on
how to the the data from the calculation thread.

Any advice or things to try?

Cheers,
Erik
--
----------------------------------------------------------------------
Erik de Castro Lopo
http://www.mega-nerd.com/

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