On 09/29/2012 08:56 AM, Ertugrul Söylemez wrote:
Or asked differently, how is the "keyDown" event defined, that was talked of in an earlier mail?
In the direct case you can define it as a simple composition:
isSym :: KeySym -> SDL.Event -> Bool isSym s (KeyDown s') = s == s' isSym _ _ = False
keyDown = require . isSym
While I understand the principals, I am unsure about the practical usage. The input of keyDown is an SDL.Event. But in an application, I would have a list of Events for every invocation of stepWire. So I could define keyDown like this: keyDown s = require . and . map (isSym s) That would give me an event when my desired keypress event is in the list of input events. but if I then want to create a wire passed in this which outputs if a given key is currently pressed, I would attempt something like this: isPressed :: KeySym -> WireP [SDL.Event] Bool isPressed s = hold . (True . (keyDown s) <|> False . (keyUp s)) But if some fast typer releases and presses within one stepWire a certain key, isPressed would produce an incorrect result. Regards, Nathan