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module tut10_4_3
// ********************************************************************************
// Clean tutorial example program.
//
// This program defines a Controls component that implements a manually settable
// counter.
// A bi-directional receiver is added to give external access to the counter value.
// ********************************************************************************
import StdEnv, StdIO
Start :: *World -> *World
Start world = startIO NDI Void initialise [] world
where
initialise pst
# (displayId, pst) = accPIO openId pst
# (resetId, pst) = accPIO openRId pst
# (readId, pst) = accPIO openR2Id pst
# (error, pst) = openDialog Void (dialog displayId resetId readId) pst
| error <> NoError = abort "Counter could not open counter dialog."
# (displayId, pst) = accPIO openId pst
# (error, pst) = openDialog Void (display displayId readId) pst
| error <> NoError = abort "Counter could not open display dialog."
| otherwise = pst
dialog displayId resetId readId = Dialog "Counter" (counter :+: resetButton) [WindowClose (noLS closeProcess)]
where
counter = { newLS = initcount,
newDef = LayoutControl (EditControl (toString initcount) (PixelWidth (hmm 50.0)) 1 [ControlId displayId, ControlSelectState Unable] :+:
ButtonControl "-" [ControlFunction (count(-1)), ControlWidth (PixelWidth (hmm 25.0)), ControlPos (BelowPrev, zero)] :+:
ButtonControl "+" [ControlFunction (count 1 ), ControlWidth (PixelWidth (hmm 25.0))] :+:
Receiver resetId reset [] :+:
Receiver2 readId read [])
[ControlPos (Center, zero), ControlHMargin 0 0, ControlVMargin 0 0, ControlItemSpace 0 0] }
where
initcount = 0
count :: Int (Int, PSt .l) -> (Int, PSt .l)
count dx (count, pst) = (count + dx, appPIO (setControlText displayId (toString (count+dx))) pst)
reset :: m (Int, PSt .l) -> (Int, PSt .l)
reset _ (_, pst) = (initcount, appPIO (setControlText displayId (toString initcount)) pst)
read :: m (Int, PSt .l) -> (Int, (Int, PSt .l))
read _ (count, pst) = (count, (count, pst))
resetButton = ButtonControl "Reset" [ControlFunction (noLS (snd o syncSend resetId undef)), ControlPos (Center, zero)]
display displayId readId = Dialog "Read" (EditControl "" (PixelWidth (hmm 50.0)) 1 [ControlId displayId, ControlSelectState Unable] :+:
ButtonControl "Read" [ControlFunction (noLS read), ControlPos (Center, zero)])
[WindowClose (noLS closeProcess)]
where
read pst
# ((error, value), pst) = syncSend2 readId undef pst
| error <> SendOk = abort "Could not read counter value"
| otherwise = appPIO (setControlText displayId (toString (fromJust value))) pst
|
