Isar theorem values within ML.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/ML/ml_thms.ML	Sat Jun 28 22:52:07 2008 +0200
@@ -0,0 +1,71 @@
+(*  Title:      Pure/ML/ml_thms.ML
+    ID:         $Id$
+    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 AuxFacts = ProofDataFun
+(
+  type T = thm list Inttab.table;
+  fun init _ = Inttab.empty;
+);
+
+val put_thms = AuxFacts.map o Inttab.update;
+
+fun the_thms ctxt name = the (Inttab.lookup (AuxFacts.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
+  (scan >> (fn ths => fn {struct_name, background} =>
+    let
+      val i = serial ();
+      val (a, background') = background
+        |> ML_Antiquote.variant kind ||> put_thms (i, ths);
+      val ml = (thm_bind kind a i, struct_name ^ "." ^ a);
+    in (K ml, background') end));
+
+val _ = thm_antiq "thm" (Attrib.thm >> single);
+val _ = thm_antiq "thms" Attrib.thms;
+
+
+(* ad-hoc goals *)
+
+fun by x = Scan.lift (Args.$$$ "by") x;
+val goal = Scan.unless by Args.prop;
+
+val _ = ML_Context.add_antiq "lemma"
+  ((Args.context -- Scan.repeat1 goal -- (by |-- Scan.lift Method.parse_args)) >>
+    (fn ((ctxt, props), method_text) => fn {struct_name, background} =>
+      let
+        val i = serial ();
+        fun after_qed [res] goal_ctxt =
+          put_thms (i, map Goal.norm_result (ProofContext.export goal_ctxt ctxt res)) goal_ctxt;
+        val ctxt' = ctxt
+          |> Proof.theorem_i NONE after_qed [map (rpair []) props]
+          |> Proof.global_terminal_proof (method_text, NONE);
+        val (a, background') = background
+          |> ML_Antiquote.variant "lemma" ||> put_thms (i, the_thms ctxt' i);
+        val ml = (thm_bind (if length props = 1 then "thm" else "thms") a i, struct_name ^ "." ^ a);
+      in (K ml, background') end));
+
+end;
+