doc-src/Codegen/Thy/examples/collect_duplicates.ML

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc-src/Codegen/Thy/examples/collect_duplicates.ML	Tue Mar 03 11:00:51 2009 +0100
@@ -0,0 +1,30 @@
+structure HOL = 
+struct
+
+type 'a eq = {eq : 'a -> 'a -> bool};
+fun eq (A_:'a eq) = #eq A_;
+
+fun eqop A_ a = eq A_ a;
+
+end; (*struct HOL*)
+
+structure List = 
+struct
+
+fun member A_ x (y :: ys) =
+  (if HOL.eqop A_ y x then true else member A_ x ys)
+  | member A_ x [] = false;
+
+end; (*struct List*)
+
+structure Codegen = 
+struct
+
+fun collect_duplicates A_ xs ys (z :: zs) =
+  (if List.member A_ z xs
+    then (if List.member A_ z ys then collect_duplicates A_ xs ys zs
+           else collect_duplicates A_ xs (z :: ys) zs)
+    else collect_duplicates A_ (z :: xs) (z :: ys) zs)
+  | collect_duplicates A_ xs ys [] = xs;
+
+end; (*struct Codegen*)