1.1 --- a/src/HOL/ex/Predicate_Compile.thy Mon Apr 20 09:32:07 2009 +0200
1.2 +++ b/src/HOL/ex/Predicate_Compile.thy Mon Apr 20 09:32:09 2009 +0200
1.3 @@ -12,26 +12,21 @@
1.4 | "next yield (Predicate.Join P xq) = (case yield P
1.5 of None \<Rightarrow> next yield xq | Some (x, Q) \<Rightarrow> Some (x, Predicate.Seq (\<lambda>_. Predicate.Join Q xq)))"
1.6
1.7 -ML {*
1.8 -let
1.9 - fun yield (@{code Predicate.Seq} f) = @{code next} yield (f ())
1.10 -in
1.11 - yield @{code "\<bottom> :: 'a Predicate.pred"} (*replace bottom with sequence to evaluate*)
1.12 -end
1.13 -*}
1.14 -
1.15 fun anamorph :: "('b \<Rightarrow> ('a \<times> 'b) option) \<Rightarrow> index \<Rightarrow> 'b \<Rightarrow> 'a list \<times> 'b" where
1.16 "anamorph f k x = (if k = 0 then ([], x)
1.17 else case f x of None \<Rightarrow> ([], x) | Some (v, y) \<Rightarrow> let (vs, z) = anamorph f (k - 1) y in (v # vs, z))"
1.18
1.19 ML {*
1.20 -let
1.21 - fun yield (@{code Predicate.Seq} f) = @{code next} yield (f ())
1.22 - fun yieldn k = @{code anamorph} yield k
1.23 -in
1.24 - yieldn 0 (*replace with number of elements to retrieve*)
1.25 - @{code "\<bottom> :: 'a Predicate.pred"} (*replace bottom with sequence to evaluate*)
1.26 -end
1.27 +structure Predicate =
1.28 +struct
1.29 +
1.30 +open Predicate;
1.31 +
1.32 +fun yield (Predicate.Seq f) = @{code next} yield (f ());
1.33 +
1.34 +fun yieldn k = @{code anamorph} yield k;
1.35 +
1.36 +end;
1.37 *}
1.38
1.39 end
1.40 \ No newline at end of file