ex 8.3 rest with copying gEq

week08/genericMap.icl

@@ -10,12 +10,11 @@ module genericMap
 
 import StdEnv, StdGeneric
 
-
 generic gMap a b :: a -> b
-gMap{|Int|}         x = x
-gMap{|Real|}        x = x
-gMap{|UNIT|}        x = x
-gMap{|PAIR|}   f g (PAIR x y) = PAIR   (f x) (g y) 
+gMap{|Int|} x 								= x
+gMap{|Real|} x 							 	= x
+gMap{|UNIT|} x 								= x
+gMap{|PAIR|} f g (PAIR x y) 	= PAIR   (f x) (g y) 
 gMap{|EITHER|} f g (LEFT x)   = LEFT   (f x)
 gMap{|EITHER|} f g (RIGHT x)  = RIGHT  (g x)
 gMap{|CONS|}   f   (CONS x)   = CONS   (f x)
@@ -41,3 +40,36 @@ tuplize n = (n, fac n)
 
 // apply the factorial function to all integers in (l, t).
 //Start = gMap{|*->*->*|} (gMap{|*->*|} fac) (gMap{|*->*|} fac) (l,t)
+
+generic gEq a :: !a !a -> Bool
+gEq{|Int|} 	x y 														= x == y
+gEq{|Char|} x y 														= x == y
+gEq{|Bool|} x y 														= x == y
+gEq{|Real|} x y 														= x == y
+gEq{|String|} x y 													= x == y
+gEq{|UNIT|} UNIT UNIT 											= True
+gEq{|PAIR|} fx fy (PAIR x1 y1) (PAIR x2 y2) = fx x1 x2 && fy y1 y2
+gEq{|EITHER|} fl fr (LEFT x) (LEFT y) 			= fl x y
+gEq{|EITHER|} fl fr (LEFT _) (RIGHT _) 			= False
+gEq{|EITHER|} fl fr (RIGHT x) (RIGHT y) 		= fr x y
+gEq{|EITHER|} fl fr (RIGHT _) (LEFT _)			= False
+gEq{|CONS|} f (CONS x) (CONS y) 						= f x y
+gEq{|RECORD|} f (RECORD x) (RECORD y) 			= f x y
+gEq{|FIELD|} f (FIELD x) (FIELD y) 					= f x y
+gEq{|OBJECT|} f (OBJECT x) (OBJECT y) 			= f x y
+
+derive gEq [], (), (,), (,,), (,,,), (,,,,), (,,,,,), (,,,,,,), (,,,,,,,)
+
+// compute the equality of [1,2] and [1,2];
+//Start = gEq{|*->*|} gEq{|*|} [1,2] [1,2]
+
+// compute the equality of [1,2] and [2,3];
+//Start = gEq{|*->*|} gEq{|*|} [1,2] [2,3]
+
+// compute the equality of [1,2] and [2,3] 
+// where you use the less-then operator < 
+// for the elements of the list. 
+// This last item is only to show you the 
+// possibilities of the generic mechanism, 
+// it is not necessarily a recommended way of working.
+//Start = gEq{|*->*|} (\x y-> not (x<y) && not (y<x)) [1,2] [2,3]
\ No newline at end of file