val kind = OuterKeyword.thy_decl

  fun trace_prop str =

     LocalTheory.theory (fn lthy => (tracing str; lthy))

  val trace_prop_parser = OuterParse.prop >> trace_prop

  val kind = OuterKeyword.thy_decl

in

  OuterSyntax.local_theory "foobar_trace" "traces a proposition"

    kind trace_prop_parser

end

*}

ML {*

let

   fun prove_prop str lthy =

     let

       val prop = Syntax.read_prop lthy str

     in

       Proof.theorem_i NONE (K I) [[(prop,[])]] lthy

     end;

   val prove_prop_parser = OuterParse.prop >> prove_prop

   val kind = OuterKeyword.thy_goal

in

   OuterSyntax.local_theory_to_proof "foobar_goal" "proving a proposition"

     kind prove_prop_parser

end

*}

ML {*

val r = ref (NONE:(unit -> term) option)

*}

ML {*

let

   fun setup_proof (txt, pos) lthy =

   let

     val trm = ML_Context.evaluate lthy true ("r", r) txt

   in

       Proof.theorem_i NONE (K I) [[(trm,[])]] lthy

   end;

   val setup_proof_parser = OuterParse.ML_source >> setup_proof

   val kind = OuterKeyword.thy_goal

in

   OuterSyntax.local_theory_to_proof "foobar_prove" "proving a proposition" 

    kind setup_proof_parser

end

*}

(*

ML {*

let

   OuterSyntax.local_theory "simple_inductive" "description of foobar" kind do_nothing

*}*)