reorganized examples directory

[coq-hetmet.git] / examples / CircuitExample.hs

diff --git a/examples/CircuitExample.hs b/examples/CircuitExample.hs
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+{-# OPTIONS_GHC -XModalTypes -ddump-types -XNoMonoPatBinds -XMultiParamTypeClasses -XTypeOperators #-}
+module CircuitExample
+where
+import GHC.HetMet.CodeTypes hiding ((-))
+import GHC.HetMet.GArrow
+import Control.Category
+import Prelude hiding ( id, (.) )
+
+--
+-- From the Appendix of Hughes' __Programming with Arrows__
+--
+
+class GArrowLoop g (**) u => GArrowCircuit g (**) u b where
+  delay :: Bool -> g b b
+
+-- GArrows which can implment LookUp Tables (LUTs)
+class GArrow g (**) u => GArrowLUT g (**) u b where
+  lut1 :: ( Bool            -> Bool) -> g  b      b
+  lut2 :: ((Bool,Bool)      -> Bool) -> g (b,b)   b
+  lut3 :: ((Bool,Bool,Bool) -> Bool) -> g (b,b,b) b
+
+nor = lut2 (not.uncurry (||))
+
+flipflop = ga_loopl $ ga_second ga_swap            >>>
+                      ga_assoc                     >>>
+                      ga_second ga_unassoc         >>>
+                      ga_second (ga_first ga_swap) >>>
+                      ga_second ga_assoc           >>>
+                      ga_unassoc                   >>>
+                      ga_first  nor                >>>
+                      ga_second nor                >>>
+                      ga_first  (delay False)      >>>
+                      ga_second (delay True)       >>>
+                      ga_copy
+
+edge = ga_copy                  >>>
+       ga_first (delay False)   >>>
+       lut2 (\(x,y) -> x && (not y))
+
+-- halfAdd :: Arrow arr => arr (Bool,Bool) (Bool,Bool)
+-- halfAdd = proc (x,y) -> returnA -< (x&&y, x/=y)
+
+-- fullAdd :: Arrow arr => arr (Bool,Bool,Bool) (Bool,Bool)
+-- fullAdd =
+--    proc (x,y,c) -> do
+--    (c1,s1) <- halfAdd -< (x,y)
+--    (c2,s2) <- halfAdd -< (s1,c)
+--    returnA -< (c1||c2,s2)