src/HOL/ex/Predicate_Compile.thy
changeset 30374 7311a1546d85
child 30810 83642621425a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/ex/Predicate_Compile.thy	Sun Mar 08 15:25:28 2009 +0100
@@ -0,0 +1,21 @@
+theory Predicate_Compile
+imports Complex_Main Lattice_Syntax
+uses "predicate_compile.ML"
+begin
+
+setup {* Predicate_Compile.setup *}
+
+primrec "next" :: "('a Predicate.pred \<Rightarrow> ('a \<times> 'a Predicate.pred) option)
+  \<Rightarrow> 'a Predicate.seq \<Rightarrow> ('a \<times> 'a Predicate.pred) option" where
+    "next yield Predicate.Empty = None"
+  | "next yield (Predicate.Insert x P) = Some (x, P)"
+  | "next yield (Predicate.Join P xq) = (case yield P
+   of None \<Rightarrow> next yield xq | Some (x, Q) \<Rightarrow> Some (x, Predicate.Seq (\<lambda>_. Predicate.Join Q xq)))"
+
+primrec pull :: "('a Predicate.pred \<Rightarrow> ('a \<times> 'a Predicate.pred) option)
+  \<Rightarrow> nat \<Rightarrow> 'a Predicate.pred \<Rightarrow> 'a list \<times> 'a Predicate.pred" where
+    "pull yield 0 P = ([], \<bottom>)"
+  | "pull yield (Suc n) P = (case yield P
+      of None \<Rightarrow> ([], \<bottom>) | Some (x, Q) \<Rightarrow> let (xs, R) = pull yield n Q in (x # xs, R))"
+
+end
\ No newline at end of file