(*  Title:      Pure/ML/ml_thms.ML

    Author:     Makarius

Isar theorem values within ML.

*)

signature ML_THMS =

sig

  val the_thms: Proof.context -> int -> thm list

  val the_thm: Proof.context -> int -> thm

end;

structure ML_Thms: ML_THMS =

struct

(* auxiliary facts table *)

structure Aux_Facts = Proof_Data

(

  type T = thm list Inttab.table;

  fun init _ = Inttab.empty;

);

val put_thms = Aux_Facts.map o Inttab.update;

fun the_thms ctxt name = the (Inttab.lookup (Aux_Facts.get ctxt) name);

fun the_thm ctxt name = the_single (the_thms ctxt name);

fun thm_bind kind a i =

  "val " ^ a ^ " = ML_Thms.the_" ^ kind ^

    " (ML_Context.the_local_context ()) " ^ string_of_int i ^ ";\n";

(* fact references *)

fun thm_antiq kind scan = ML_Context.add_antiq kind

  (fn _ => scan >> (fn ths => fn background =>

    let

      val i = serial ();

      val (a, background') = background

        |> ML_Antiquote.variant kind ||> put_thms (i, ths);

      val ml = (thm_bind kind a i, "Isabelle." ^ a);

    in (K ml, background') end));

val _ = thm_antiq "thm" (Attrib.thm >> single);

val _ = thm_antiq "thms" Attrib.thms;

(* ad-hoc goals *)

val and_ = Args.$$$ "and";

val by = Args.$$$ "by";

val goal = Scan.unless (by || and_) Args.name;

val _ = ML_Context.add_antiq "lemma"

  (fn _ => Args.context -- Args.mode "open" --

      Scan.lift (Parse.and_list1 (Scan.repeat1 goal) --

        (by |-- Method.parse -- Scan.option Method.parse)) >>

    (fn ((ctxt, is_open), (raw_propss, methods)) => fn background =>

      let

        val propss = burrow (map (rpair []) o Syntax.read_props ctxt) raw_propss;

        val i = serial ();

        val prep_result = Goal.norm_result #> not is_open ? Thm.close_derivation;

        fun after_qed res goal_ctxt =

          put_thms (i, map prep_result (ProofContext.export goal_ctxt ctxt (flat res))) goal_ctxt;

        val ctxt' = ctxt

          |> Proof.theorem NONE after_qed propss

          |> Proof.global_terminal_proof methods;

        val (a, background') = background

          |> ML_Antiquote.variant "lemma" ||> put_thms (i, the_thms ctxt' i);

        val ml =

          (thm_bind (if length (flat propss) = 1 then "thm" else "thms") a i, "Isabelle." ^ a);

      in (K ml, background') end));

end;