content: -- Copyright © 2011 National Institute of Aerospace / Galois, Inc.
  
  -- | Example implementing an engine cooling control system.
  
  {-# LANGUAGE RebindableSyntax #-}
  
  module Main where
  
  import Language.Copilot
  import qualified Prelude as P
  
  -- If the majority of the engine temperature probes exeeds 250 degrees, then
  -- the cooler is engaged and remains engaged until the majority of the engine
  -- temperature probes drop to 250 or below.  Otherwise, trigger an immediate
  -- shutdown of the engine.
  
  engineMonitor :: Spec
  engineMonitor = do
    trigger "shutoff" (not ok) [arg maj]
  
    where
    vals     = [ externW8 "tmp_probe_0" two51
               , externW8 "tmp_probe_1" two51
               , externW8 "tmp_probe_2" zero]
    exceed   = map (> 250) vals
    maj      = majority exceed
    checkMaj = aMajority exceed maj
    ok       = alwaysBeen ((maj && checkMaj) ==> extern "cooler" cooler)
  
    two51  = Just $ [251, 251] P.++ repeat (250 :: Word8)
    zero   = Just $ repeat (0 :: Word8)
    cooler = Just $ [True, True] P.++ repeat False
  
  main :: IO ()
  main = interpret 10 engineMonitor
  