--- a/src/HOL/ex/Normalization_by_Evaluation.thy Fri Nov 26 23:12:01 2010 +0100
+++ b/src/HOL/ex/Normalization_by_Evaluation.thy Fri Nov 26 23:14:14 2010 +0100
@@ -66,7 +66,7 @@
lemma "map (%f. f True) [id, g, Not] = [True, g True, False]" by normalization
lemma "map (%f. f True) ([id, g, Not] @ fs) = [True, g True, False] @ map (%f. f True) fs"
- by normalization rule+
+ by normalization
lemma "rev [a, b, c] = [c, b, a]" by normalization
value [nbe] "rev (a#b#cs) = rev cs @ [b, a]"
value [nbe] "map (%F. F [a,b,c::'x]) (map map [f,g,h])"
@@ -108,10 +108,13 @@
lemma "(42::rat) / 1704 = 1 / 284 + 3 / 142" by normalization
value [nbe] "Suc 0 \<in> set ms"
+(* non-left-linear patterns, equality by extensionality *)
+
lemma "f = f" by normalization
lemma "f x = f x" by normalization
lemma "(f o g) x = f (g x)" by normalization
lemma "(f o id) x = f x" by normalization
+lemma "(id :: bool \<Rightarrow> bool) = id" by normalization
value [nbe] "(\<lambda>x. x)"
(* Church numerals: *)
--- a/src/Pure/library.ML Fri Nov 26 23:12:01 2010 +0100
+++ b/src/Pure/library.ML Fri Nov 26 23:14:14 2010 +0100
@@ -546,7 +546,7 @@
fun forall2 P [] [] = true
| forall2 P (x :: xs) (y :: ys) = P x y andalso forall2 P xs ys
- | forall2 P _ _ = false;
+ | forall2 P _ _ = raise UnequalLengths;
fun map_split f [] = ([], [])
| map_split f (x :: xs) =
--- a/src/Tools/nbe.ML Fri Nov 26 23:12:01 2010 +0100
+++ b/src/Tools/nbe.ML Fri Nov 26 23:14:14 2010 +0100
@@ -18,7 +18,7 @@
val apps: Univ -> Univ list -> Univ (*explicit applications*)
val abss: int -> (Univ list -> Univ) -> Univ
(*abstractions as closures*)
- val same: Univ -> Univ -> bool
+ val eq_Univ: Univ * Univ -> bool
val put_result: (unit -> Univ list -> Univ list) -> Proof.context -> Proof.context
val trace: bool Unsynchronized.ref
@@ -170,11 +170,6 @@
| Abs of (int * (Univ list -> Univ)) * Univ list
(*abstractions as closures*);
-fun same (Const (k, xs)) (Const (l, ys)) = k = l andalso forall2 same xs ys
- | same (DFree (s, k)) (DFree (t, l)) = s = t andalso k = l
- | same (BVar (k, xs)) (BVar (l, ys)) = k = l andalso forall2 same xs ys
- | same _ _ = false;
-
(* constructor functions *)
@@ -188,6 +183,28 @@
| apps (Const (name, xs)) ys = Const (name, ys @ xs)
| apps (BVar (n, xs)) ys = BVar (n, ys @ xs);
+fun satisfy_abs (abs as ((n, f), xs)) some_k =
+ let
+ val ys = case some_k
+ of NONE => replicate n (BVar (0, []))
+ | SOME k => map_range (fn l => BVar (k + l, [])) n;
+ in (apps (Abs abs) ys, ys) end;
+
+fun maxidx (Const (_, xs)) = fold maxidx xs
+ | maxidx (DFree _) = I
+ | maxidx (BVar (l, xs)) = fold maxidx xs #> Integer.max (l + 1)
+ | maxidx (Abs abs) = maxidx (fst (satisfy_abs abs NONE));
+
+fun eq_Univ (Const (k, xs), Const (l, ys)) = k = l andalso eq_list eq_Univ (xs, ys)
+ | eq_Univ (DFree (s, k), DFree (t, l)) = s = t andalso k = l
+ | eq_Univ (BVar (k, xs), BVar (l, ys)) = k = l andalso eq_list eq_Univ (xs, ys)
+ | eq_Univ (x as Abs abs, y) =
+ let
+ val (x, ys) = satisfy_abs abs ((SOME o maxidx x o maxidx y) 0)
+ in eq_Univ (x, apps y ys) end
+ | eq_Univ (x, y as Abs _) = eq_Univ (y, x)
+ | eq_Univ _ = false;
+
(** assembling and compiling ML code from terms **)
@@ -241,7 +258,7 @@
val name_const = prefix ^ "Const";
val name_abss = prefix ^ "abss";
val name_apps = prefix ^ "apps";
- val name_same = prefix ^ "same";
+ val name_eq = prefix ^ "eq_Univ";
in
val univs_cookie = (Univs.get, put_result, name_put);
@@ -267,7 +284,7 @@
fun nbe_abss 0 f = f `$` ml_list []
| nbe_abss n f = name_abss `$$` [string_of_int n, f];
-fun nbe_same v1 v2 = "(" ^ name_same ^ " " ^ nbe_bound v1 ^ " " ^ nbe_bound v2 ^ ")";
+fun nbe_eq (v1, v2) = "(" ^ name_eq ^ " (" ^ nbe_bound v1 ^ ", " ^ nbe_bound v2 ^ "))";
end;
@@ -353,7 +370,7 @@
val (samepairs, args') = subst_nonlin_vars args;
val s_args = map assemble_arg args';
val s_rhs = if null samepairs then assemble_rhs rhs
- else ml_if (ml_and (map (uncurry nbe_same) samepairs))
+ else ml_if (ml_and (map nbe_eq samepairs))
(assemble_rhs rhs) default_rhs;
val eqns = if is_eval then
[([ml_list (rev (dicts @ s_args))], s_rhs)]