src/HOL/ex/SVC_Oracle.thy

 
 header {* Installing an oracle for SVC (Stanford Validity Checker) *}
 
 theory SVC_Oracle
 imports Main
-uses "svc_funcs.ML" ("svc_oracle.ML")
+uses "svc_funcs.ML"
 begin
 
 consts
   iff_keep :: "[bool, bool] => bool"
   iff_unfold :: "[bool, bool] => bool"

 hide const iff_keep iff_unfold
 
 oracle
   svc_oracle ("term") = Svc.oracle
 
-use "svc_oracle.ML"
+ML {*
+(*
+Installing the oracle for SVC (Stanford Validity Checker)
+
+The following code merely CALLS the oracle;
+  the soundness-critical functions are at svc_funcs.ML
+
+Based upon the work of Søren T. Heilmann
+*)
+
+
+(*Generalize an Isabelle formula, replacing by Vars
+  all subterms not intelligible to SVC.*)
+fun svc_abstract t =
+  let
+    (*The oracle's result is given to the subgoal using compose_tac because
+      its premises are matched against the assumptions rather than used
+      to make subgoals.  Therefore , abstraction must copy the parameters
+      precisely and make them available to all generated Vars.*)
+    val params = Term.strip_all_vars t
+    and body   = Term.strip_all_body t
+    val Us = map #2 params
+    val nPar = length params
+    val vname = ref "V_a"
+    val pairs = ref ([] : (term*term) list)
+    fun insert t =
+        let val T = fastype_of t
+            val v = Logic.combound (Var ((!vname,0), Us--->T), 0, nPar)
+        in  vname := Symbol.bump_string (!vname);
+            pairs := (t, v) :: !pairs;
+            v
+        end;
+    fun replace t =
+        case t of
+            Free _  => t  (*but not existing Vars, lest the names clash*)
+          | Bound _ => t
+          | _ => (case AList.lookup Pattern.aeconv (!pairs) t of
+                      SOME v => v
+                    | NONE   => insert t)
+    (*abstraction of a numeric literal*)
+    fun lit (t as Const(@{const_name HOL.zero}, _)) = t
+      | lit (t as Const(@{const_name HOL.one}, _)) = t
+      | lit (t as Const(@{const_name Numeral.number_of}, _) $ w) = t
+      | lit t = replace t
+    (*abstraction of a real/rational expression*)
+    fun rat ((c as Const(@{const_name HOL.plus}, _)) $ x $ y) = c $ (rat x) $ (rat y)
+      | rat ((c as Const(@{const_name HOL.minus}, _)) $ x $ y) = c $ (rat x) $ (rat y)
+      | rat ((c as Const(@{const_name HOL.divide}, _)) $ x $ y) = c $ (rat x) $ (rat y)
+      | rat ((c as Const(@{const_name HOL.times}, _)) $ x $ y) = c $ (rat x) $ (rat y)
+      | rat ((c as Const(@{const_name HOL.uminus}, _)) $ x) = c $ (rat x)
+      | rat t = lit t
+    (*abstraction of an integer expression: no div, mod*)
+    fun int ((c as Const(@{const_name HOL.plus}, _)) $ x $ y) = c $ (int x) $ (int y)
+      | int ((c as Const(@{const_name HOL.minus}, _)) $ x $ y) = c $ (int x) $ (int y)
+      | int ((c as Const(@{const_name HOL.times}, _)) $ x $ y) = c $ (int x) $ (int y)
+      | int ((c as Const(@{const_name HOL.uminus}, _)) $ x) = c $ (int x)
+      | int t = lit t
+    (*abstraction of a natural number expression: no minus*)
+    fun nat ((c as Const(@{const_name HOL.plus}, _)) $ x $ y) = c $ (nat x) $ (nat y)
+      | nat ((c as Const(@{const_name HOL.times}, _)) $ x $ y) = c $ (nat x) $ (nat y)
+      | nat ((c as Const(@{const_name Suc}, _)) $ x) = c $ (nat x)
+      | nat t = lit t
+    (*abstraction of a relation: =, <, <=*)
+    fun rel (T, c $ x $ y) =
+            if T = HOLogic.realT then c $ (rat x) $ (rat y)
+            else if T = HOLogic.intT then c $ (int x) $ (int y)
+            else if T = HOLogic.natT then c $ (nat x) $ (nat y)
+            else if T = HOLogic.boolT then c $ (fm x) $ (fm y)
+            else replace (c $ x $ y)   (*non-numeric comparison*)
+    (*abstraction of a formula*)
+    and fm ((c as Const("op &", _)) $ p $ q) = c $ (fm p) $ (fm q)
+      | fm ((c as Const("op |", _)) $ p $ q) = c $ (fm p) $ (fm q)
+      | fm ((c as Const("op -->", _)) $ p $ q) = c $ (fm p) $ (fm q)
+      | fm ((c as Const("Not", _)) $ p) = c $ (fm p)
+      | fm ((c as Const("True", _))) = c
+      | fm ((c as Const("False", _))) = c
+      | fm (t as Const("op =",  Type ("fun", [T,_])) $ _ $ _) = rel (T, t)
+      | fm (t as Const(@{const_name HOL.less},  Type ("fun", [T,_])) $ _ $ _) = rel (T, t)
+      | fm (t as Const(@{const_name HOL.less_eq}, Type ("fun", [T,_])) $ _ $ _) = rel (T, t)
+      | fm t = replace t
+    (*entry point, and abstraction of a meta-formula*)
+    fun mt ((c as Const("Trueprop", _)) $ p) = c $ (fm p)
+      | mt ((c as Const("==>", _)) $ p $ q)  = c $ (mt p) $ (mt q)
+      | mt t = fm t  (*it might be a formula*)
+  in (list_all (params, mt body), !pairs) end;
+
+
+(*Present the entire subgoal to the oracle, assumptions and all, but possibly
+  abstracted.  Use via compose_tac, which performs no lifting but will
+  instantiate variables.*)
+
+fun svc_tac i st =
+  let
+    val (abs_goal, _) = svc_abstract (Logic.get_goal (Thm.prop_of st) i)
+    val th = svc_oracle (Thm.theory_of_thm st) abs_goal
+   in compose_tac (false, th, 0) i st end
+   handle TERM _ => no_tac st;
+
+
+(*check if user has SVC installed*)
+fun svc_enabled () = getenv "SVC_HOME" <> "";
+fun if_svc_enabled f x = if svc_enabled () then f x else ();
+*}
 
 end