Add optimization cases for triage and composition

lib/base.tri

@@ -7,17 +7,14 @@ s     = t (t (k t)) t
 m     = s i i
 b     = s (k s) k
 c     = s (s (k s) (s (k k) s)) (k k)
-iC    = (\a b c : s a (k c) b)
-iD    = b (b iC) iC
-iE    = b (b iD) iC
-yi    = (\i : b m (c b (i m)))
-y     = yi iC
-yC    = yi iD
-yD    = yi iE
 id    = (\a : a)
 pair  = t
 if    = (\cond then else : t (t else (t t then)) t cond)
 
+y = ((\mut wait fun : wait mut (\x : fun (wait mut x)))
+     (\x : x x)
+     (\a0 a1 a2 : t (t a0) (t t a2) a1))
+
 triage = (\leaf stem fork : t (t leaf stem) fork)
 test   = triage "Leaf" (\_ : "Stem") (\_ _ : "Fork")