src/HOL/Predicate.thy
 changeset 31108 0ce5f53fc65d parent 31106 9a1178204dc0 parent 30959 458e55fd0a33 child 31109 54092b86ef81
```     1.1 --- a/src/HOL/Predicate.thy	Mon May 11 09:39:53 2009 +0200
1.2 +++ b/src/HOL/Predicate.thy	Mon May 11 17:20:52 2009 +0200
1.3 @@ -625,7 +625,56 @@
1.4  inductive eq :: "'a \<Rightarrow> 'a \<Rightarrow> bool" where "eq x x"
1.5
1.6  lemma eq_is_eq: "eq x y \<equiv> (x = y)"
1.7 -by (rule eq_reflection) (auto intro: eq.intros elim: eq.cases)
1.8 +  by (rule eq_reflection) (auto intro: eq.intros elim: eq.cases)
1.9 +
1.10 +ML {*
1.11 +signature PREDICATE =
1.12 +sig
1.13 +  datatype 'a pred = Seq of (unit -> 'a seq)
1.14 +  and 'a seq = Empty | Insert of 'a * 'a pred | Join of 'a pred * 'a seq
1.15 +  val yield: 'a pred -> ('a * 'a pred) option
1.16 +  val yieldn: int -> 'a pred -> 'a list * 'a pred
1.17 +end;
1.18 +
1.19 +structure Predicate : PREDICATE =
1.20 +struct
1.21 +
1.22 +@{code_datatype pred = Seq};
1.23 +@{code_datatype seq = Empty | Insert | Join};
1.24 +
1.25 +fun yield (Seq f) = next (f ())
1.26 +and next @{code Empty} = NONE
1.27 +  | next (@{code Insert} (x, P)) = SOME (x, P)
1.28 +  | next (@{code Join} (P, xq)) = (case yield P
1.29 +     of NONE => next xq
1.30 +      | SOME (x, Q) => SOME (x, @{code Seq} (fn _ => @{code Join} (Q, xq))))
1.31 +
1.32 +fun anamorph f k x = (if k = 0 then ([], x)
1.33 +  else case f x
1.34 +   of NONE => ([], x)
1.35 +    | SOME (v, y) => let
1.36 +        val (vs, z) = anamorph f (k - 1) y
1.37 +      in (v :: vs, z) end)
1.38 +
1.39 +fun yieldn P = anamorph yield P;
1.40 +
1.41 +end;
1.42 +*}
1.43 +
1.44 +code_reserved Eval Predicate
1.45 +
1.46 +code_type pred and seq
1.47 +  (Eval "_/ Predicate.pred" and "_/ Predicate.seq")
1.48 +
1.49 +code_const Seq and Empty and Insert and Join
1.50 +  (Eval "Predicate.Seq" and "Predicate.Empty" and "Predicate.Insert/ (_,/ _)" and "Predicate.Join/ (_,/ _)")
1.51 +
1.52 +text {* dummy setup for code_pred keyword *}
1.53 +
1.54 +ML {*
1.55 +OuterSyntax.local_theory_to_proof "code_pred" "sets up goal for cases rule from given introduction rules and compiles predicate"
1.56 +  OuterKeyword.thy_goal (OuterParse.term_group >> (K (Proof.theorem_i NONE (K I) [[]])))
1.57 +*}
1.58
1.59  no_notation
1.60    inf (infixl "\<sqinter>" 70) and
1.61 @@ -640,12 +689,4 @@
1.62  hide (open) const Pred eval single bind if_pred not_pred
1.63    Empty Insert Join Seq member pred_of_seq "apply" adjunct eq
1.64
1.65 -text {* dummy setup for code_pred keyword *}
1.66 -
1.67 -ML {*
1.68 -OuterSyntax.local_theory_to_proof "code_pred" "sets up goal for cases rule from given introduction rules and compiles predicate"
1.69 -  OuterKeyword.thy_goal (OuterParse.term_group >> (K (Proof.theorem_i NONE (K I) [[]])))
1.70 -*}
1.71 -
1.72 -
1.73  end
```