renamed Pure/tctical.ML to Pure/tactical.ML;
authorwenzelm
Fri, 24 Jul 2009 12:00:02 +0200
changeset 32169 fbada8ed12e6
parent 32168 116461b8fc01
child 32170 541b35729992
renamed Pure/tctical.ML to Pure/tactical.ML;
src/Pure/General/seq.ML
src/Pure/IsaMakefile
src/Pure/ROOT.ML
src/Pure/tactical.ML
src/Pure/tctical.ML
--- a/src/Pure/General/seq.ML	Fri Jul 24 11:55:34 2009 +0200
+++ b/src/Pure/General/seq.ML	Fri Jul 24 12:00:02 2009 +0200
@@ -200,7 +200,7 @@
 
 
 
-(** sequence functions **)      (*cf. Pure/tctical.ML*)
+(** sequence functions **)      (*cf. Pure/tactical.ML*)
 
 fun succeed x = single x;
 fun fail _ = empty;
--- a/src/Pure/IsaMakefile	Fri Jul 24 11:55:34 2009 +0200
+++ b/src/Pure/IsaMakefile	Fri Jul 24 12:00:02 2009 +0200
@@ -94,7 +94,7 @@
   item_net.ML library.ML logic.ML meta_simplifier.ML more_thm.ML	\
   morphism.ML name.ML net.ML old_goals.ML old_term.ML pattern.ML	\
   primitive_defs.ML proofterm.ML pure_setup.ML pure_thy.ML search.ML	\
-  sign.ML simplifier.ML sorts.ML subgoal.ML tactic.ML tctical.ML	\
+  sign.ML simplifier.ML sorts.ML subgoal.ML tactic.ML tactical.ML	\
   term.ML term_ord.ML term_subst.ML theory.ML thm.ML type.ML		\
   type_infer.ML unify.ML variable.ML
 	@./mk
--- a/src/Pure/ROOT.ML	Fri Jul 24 11:55:34 2009 +0200
+++ b/src/Pure/ROOT.ML	Fri Jul 24 12:00:02 2009 +0200
@@ -120,7 +120,7 @@
 use "variable.ML";
 use "conv.ML";
 use "display_goal.ML";
-use "tctical.ML";
+use "tactical.ML";
 use "search.ML";
 use "tactic.ML";
 use "meta_simplifier.ML";
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/tactical.ML	Fri Jul 24 12:00:02 2009 +0200
@@ -0,0 +1,524 @@
+(*  Title:      Pure/tactical.ML
+    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
+
+Tacticals.
+*)
+
+infix 1 THEN THEN' THEN_ALL_NEW;
+infix 0 ORELSE APPEND INTLEAVE ORELSE' APPEND' INTLEAVE';
+infix 0 THEN_ELSE;
+
+signature TACTICAL =
+sig
+  type tactic = thm -> thm Seq.seq
+  val THEN: tactic * tactic -> tactic
+  val ORELSE: tactic * tactic -> tactic
+  val APPEND: tactic * tactic -> tactic
+  val INTLEAVE: tactic * tactic -> tactic
+  val THEN_ELSE: tactic * (tactic*tactic) -> tactic
+  val THEN': ('a -> tactic) * ('a -> tactic) -> 'a -> tactic
+  val ORELSE': ('a -> tactic) * ('a -> tactic) -> 'a -> tactic
+  val APPEND': ('a -> tactic) * ('a -> tactic) -> 'a -> tactic
+  val INTLEAVE': ('a -> tactic) * ('a -> tactic) -> 'a -> tactic
+  val all_tac: tactic
+  val no_tac: tactic
+  val DETERM: tactic -> tactic
+  val COND: (thm -> bool) -> tactic -> tactic -> tactic
+  val TRY: tactic -> tactic
+  val EVERY: tactic list -> tactic
+  val EVERY': ('a -> tactic) list -> 'a -> tactic
+  val EVERY1: (int -> tactic) list -> tactic
+  val FIRST: tactic list -> tactic
+  val FIRST': ('a -> tactic) list -> 'a -> tactic
+  val FIRST1: (int -> tactic) list -> tactic
+  val RANGE: (int -> tactic) list -> int -> tactic
+  val print_tac: string -> tactic
+  val pause_tac: tactic
+  val trace_REPEAT: bool ref
+  val suppress_tracing: bool ref
+  val tracify: bool ref -> tactic -> tactic
+  val traced_tac: (thm -> (thm * thm Seq.seq) option) -> tactic
+  val DETERM_UNTIL: (thm -> bool) -> tactic -> tactic
+  val REPEAT_DETERM_N: int -> tactic -> tactic
+  val REPEAT_DETERM: tactic -> tactic
+  val REPEAT: tactic -> tactic
+  val REPEAT_DETERM1: tactic -> tactic
+  val REPEAT1: tactic -> tactic
+  val FILTER: (thm -> bool) -> tactic -> tactic
+  val CHANGED: tactic -> tactic
+  val CHANGED_PROP: tactic -> tactic
+  val ALLGOALS: (int -> tactic) -> tactic
+  val SOMEGOAL: (int -> tactic) -> tactic
+  val FIRSTGOAL: (int -> tactic) -> tactic
+  val REPEAT_SOME: (int -> tactic) -> tactic
+  val REPEAT_DETERM_SOME: (int -> tactic) -> tactic
+  val REPEAT_FIRST: (int -> tactic) -> tactic
+  val REPEAT_DETERM_FIRST: (int -> tactic) -> tactic
+  val TRYALL: (int -> tactic) -> tactic
+  val CSUBGOAL: ((cterm * int) -> tactic) -> int -> tactic
+  val SUBGOAL: ((term * int) -> tactic) -> int -> tactic
+  val CHANGED_GOAL: (int -> tactic) -> int -> tactic
+  val THEN_ALL_NEW: (int -> tactic) * (int -> tactic) -> int -> tactic
+  val REPEAT_ALL_NEW: (int -> tactic) -> int -> tactic
+  val strip_context: term -> (string * typ) list * term list * term
+  val metahyps_thms: int -> thm -> thm list option
+  val METAHYPS: (thm list -> tactic) -> int -> tactic
+  val PRIMSEQ: (thm -> thm Seq.seq) -> tactic
+  val PRIMITIVE: (thm -> thm) -> tactic
+  val SINGLE: tactic -> thm -> thm option
+  val CONVERSION: conv -> int -> tactic
+end;
+
+structure Tactical : TACTICAL =
+struct
+
+(**** Tactics ****)
+
+(*A tactic maps a proof tree to a sequence of proof trees:
+    if length of sequence = 0 then the tactic does not apply;
+    if length > 1 then backtracking on the alternatives can occur.*)
+
+type tactic = thm -> thm Seq.seq;
+
+
+(*** LCF-style tacticals ***)
+
+(*the tactical THEN performs one tactic followed by another*)
+fun (tac1 THEN tac2) st = Seq.maps tac2 (tac1 st);
+
+
+(*The tactical ORELSE uses the first tactic that returns a nonempty sequence.
+  Like in LCF, ORELSE commits to either tac1 or tac2 immediately.
+  Does not backtrack to tac2 if tac1 was initially chosen. *)
+fun (tac1 ORELSE tac2) st =
+    case Seq.pull(tac1 st) of
+        NONE       => tac2 st
+      | sequencecell => Seq.make(fn()=> sequencecell);
+
+
+(*The tactical APPEND combines the results of two tactics.
+  Like ORELSE, but allows backtracking on both tac1 and tac2.
+  The tactic tac2 is not applied until needed.*)
+fun (tac1 APPEND tac2) st =
+  Seq.append (tac1 st) (Seq.make(fn()=> Seq.pull (tac2 st)));
+
+(*Like APPEND, but interleaves results of tac1 and tac2.*)
+fun (tac1 INTLEAVE tac2) st =
+    Seq.interleave(tac1 st,
+                        Seq.make(fn()=> Seq.pull (tac2 st)));
+
+(*Conditional tactic.
+        tac1 ORELSE tac2 = tac1 THEN_ELSE (all_tac, tac2)
+        tac1 THEN tac2   = tac1 THEN_ELSE (tac2, no_tac)
+*)
+fun (tac THEN_ELSE (tac1, tac2)) st =
+    case Seq.pull(tac st) of
+        NONE    => tac2 st                                   (*failed; try tactic 2*)
+      | seqcell => Seq.maps tac1 (Seq.make(fn()=> seqcell)); (*succeeded; use tactic 1*)
+
+
+(*Versions for combining tactic-valued functions, as in
+     SOMEGOAL (resolve_tac rls THEN' assume_tac) *)
+fun (tac1 THEN' tac2) x = tac1 x THEN tac2 x;
+fun (tac1 ORELSE' tac2) x = tac1 x ORELSE tac2 x;
+fun (tac1 APPEND' tac2) x = tac1 x APPEND tac2 x;
+fun (tac1 INTLEAVE' tac2) x = tac1 x INTLEAVE tac2 x;
+
+(*passes all proofs through unchanged;  identity of THEN*)
+fun all_tac st = Seq.single st;
+
+(*passes no proofs through;  identity of ORELSE and APPEND*)
+fun no_tac st  = Seq.empty;
+
+
+(*Make a tactic deterministic by chopping the tail of the proof sequence*)
+fun DETERM tac = Seq.DETERM tac;
+
+(*Conditional tactical: testfun controls which tactic to use next.
+  Beware: due to eager evaluation, both thentac and elsetac are evaluated.*)
+fun COND testfun thenf elsef = (fn prf =>
+    if testfun prf then  thenf prf   else  elsef prf);
+
+(*Do the tactic or else do nothing*)
+fun TRY tac = tac ORELSE all_tac;
+
+(*** List-oriented tactics ***)
+
+local
+  (*This version of EVERY avoids backtracking over repeated states*)
+
+  fun EVY (trail, []) st =
+        Seq.make (fn()=> SOME(st,
+                        Seq.make (fn()=> Seq.pull (evyBack trail))))
+    | EVY (trail, tac::tacs) st =
+          case Seq.pull(tac st) of
+              NONE    => evyBack trail              (*failed: backtrack*)
+            | SOME(st',q) => EVY ((st',q,tacs)::trail, tacs) st'
+  and evyBack [] = Seq.empty (*no alternatives*)
+    | evyBack ((st',q,tacs)::trail) =
+          case Seq.pull q of
+              NONE        => evyBack trail
+            | SOME(st,q') => if Thm.eq_thm (st',st)
+                             then evyBack ((st',q',tacs)::trail)
+                             else EVY ((st,q',tacs)::trail, tacs) st
+in
+
+(* EVERY [tac1,...,tacn]   equals    tac1 THEN ... THEN tacn   *)
+fun EVERY tacs = EVY ([], tacs);
+end;
+
+
+(* EVERY' [tac1,...,tacn] i  equals    tac1 i THEN ... THEN tacn i   *)
+fun EVERY' tacs i = EVERY (map (fn f => f i) tacs);
+
+(*Apply every tactic to 1*)
+fun EVERY1 tacs = EVERY' tacs 1;
+
+(* FIRST [tac1,...,tacn]   equals    tac1 ORELSE ... ORELSE tacn   *)
+fun FIRST tacs = fold_rev (curry op ORELSE) tacs no_tac;
+
+(* FIRST' [tac1,...,tacn] i  equals    tac1 i ORELSE ... ORELSE tacn i   *)
+fun FIRST' tacs = fold_rev (curry op ORELSE') tacs (K no_tac);
+
+(*Apply first tactic to 1*)
+fun FIRST1 tacs = FIRST' tacs 1;
+
+(*Apply tactics on consecutive subgoals*)
+fun RANGE [] _ = all_tac
+  | RANGE (tac :: tacs) i = RANGE tacs (i + 1) THEN tac i;
+
+
+(*** Tracing tactics ***)
+
+(*Print the current proof state and pass it on.*)
+fun print_tac msg st =
+ (tracing (msg ^ "\n" ^
+    Pretty.string_of (Pretty.chunks
+      (Display_Goal.pretty_goals_without_context (! Display_Goal.goals_limit) st)));
+  Seq.single st);
+
+(*Pause until a line is typed -- if non-empty then fail. *)
+fun pause_tac st =
+  (tracing "** Press RETURN to continue:";
+   if TextIO.inputLine TextIO.stdIn = SOME "\n" then Seq.single st
+   else (tracing "Goodbye";  Seq.empty));
+
+exception TRACE_EXIT of thm
+and TRACE_QUIT;
+
+(*Tracing flags*)
+val trace_REPEAT= ref false
+and suppress_tracing = ref false;
+
+(*Handle all tracing commands for current state and tactic *)
+fun exec_trace_command flag (tac, st) =
+   case TextIO.inputLine TextIO.stdIn of
+       SOME "\n" => tac st
+     | SOME "f\n" => Seq.empty
+     | SOME "o\n" => (flag:=false;  tac st)
+     | SOME "s\n" => (suppress_tracing:=true;  tac st)
+     | SOME "x\n" => (tracing "Exiting now";  raise (TRACE_EXIT st))
+     | SOME "quit\n" => raise TRACE_QUIT
+     | _     => (tracing
+"Type RETURN to continue or...\n\
+\     f    - to fail here\n\
+\     o    - to switch tracing off\n\
+\     s    - to suppress tracing until next entry to a tactical\n\
+\     x    - to exit at this point\n\
+\     quit - to abort this tracing run\n\
+\** Well? "     ;  exec_trace_command flag (tac, st));
+
+
+(*Extract from a tactic, a thm->thm seq function that handles tracing*)
+fun tracify flag tac st =
+  if !flag andalso not (!suppress_tracing) then
+    (tracing (Pretty.string_of (Pretty.chunks
+        (Display_Goal.pretty_goals_without_context (! Display_Goal.goals_limit) st @
+          [Pretty.str "** Press RETURN to continue:"])));
+     exec_trace_command flag (tac, st))
+  else tac st;
+
+(*Create a tactic whose outcome is given by seqf, handling TRACE_EXIT*)
+fun traced_tac seqf st =
+    (suppress_tracing := false;
+     Seq.make (fn()=> seqf st
+                         handle TRACE_EXIT st' => SOME(st', Seq.empty)));
+
+
+(*Deterministic DO..UNTIL: only retains the first outcome; tail recursive.
+  Forces repitition until predicate on state is fulfilled.*)
+fun DETERM_UNTIL p tac =
+let val tac = tracify trace_REPEAT tac
+    fun drep st = if p st then SOME (st, Seq.empty)
+                          else (case Seq.pull(tac st) of
+                                  NONE        => NONE
+                                | SOME(st',_) => drep st')
+in  traced_tac drep  end;
+
+(*Deterministic REPEAT: only retains the first outcome;
+  uses less space than REPEAT; tail recursive.
+  If non-negative, n bounds the number of repetitions.*)
+fun REPEAT_DETERM_N n tac =
+  let val tac = tracify trace_REPEAT tac
+      fun drep 0 st = SOME(st, Seq.empty)
+        | drep n st =
+           (case Seq.pull(tac st) of
+                NONE       => SOME(st, Seq.empty)
+              | SOME(st',_) => drep (n-1) st')
+  in  traced_tac (drep n)  end;
+
+(*Allows any number of repetitions*)
+val REPEAT_DETERM = REPEAT_DETERM_N ~1;
+
+(*General REPEAT: maintains a stack of alternatives; tail recursive*)
+fun REPEAT tac =
+  let val tac = tracify trace_REPEAT tac
+      fun rep qs st =
+        case Seq.pull(tac st) of
+            NONE       => SOME(st, Seq.make(fn()=> repq qs))
+          | SOME(st',q) => rep (q::qs) st'
+      and repq [] = NONE
+        | repq(q::qs) = case Seq.pull q of
+            NONE       => repq qs
+          | SOME(st,q) => rep (q::qs) st
+  in  traced_tac (rep [])  end;
+
+(*Repeat 1 or more times*)
+fun REPEAT_DETERM1 tac = DETERM tac THEN REPEAT_DETERM tac;
+fun REPEAT1 tac = tac THEN REPEAT tac;
+
+
+(** Filtering tacticals **)
+
+fun FILTER pred tac st = Seq.filter pred (tac st);
+
+(*Accept only next states that change the theorem somehow*)
+fun CHANGED tac st =
+  let fun diff st' = not (Thm.eq_thm (st, st'));
+  in Seq.filter diff (tac st) end;
+
+(*Accept only next states that change the theorem's prop field
+  (changes to signature, hyps, etc. don't count)*)
+fun CHANGED_PROP tac st =
+  let fun diff st' = not (Thm.eq_thm_prop (st, st'));
+  in Seq.filter diff (tac st) end;
+
+
+(*** Tacticals based on subgoal numbering ***)
+
+(*For n subgoals, performs tac(n) THEN ... THEN tac(1)
+  Essential to work backwards since tac(i) may add/delete subgoals at i. *)
+fun ALLGOALS tac st =
+  let fun doall 0 = all_tac
+        | doall n = tac(n) THEN doall(n-1)
+  in  doall(nprems_of st)st  end;
+
+(*For n subgoals, performs tac(n) ORELSE ... ORELSE tac(1)  *)
+fun SOMEGOAL tac st =
+  let fun find 0 = no_tac
+        | find n = tac(n) ORELSE find(n-1)
+  in  find(nprems_of st)st  end;
+
+(*For n subgoals, performs tac(1) ORELSE ... ORELSE tac(n).
+  More appropriate than SOMEGOAL in some cases.*)
+fun FIRSTGOAL tac st =
+  let fun find (i,n) = if i>n then no_tac else  tac(i) ORELSE find (i+1,n)
+  in  find(1, nprems_of st)st  end;
+
+(*Repeatedly solve some using tac. *)
+fun REPEAT_SOME tac = REPEAT1 (SOMEGOAL (REPEAT1 o tac));
+fun REPEAT_DETERM_SOME tac = REPEAT_DETERM1 (SOMEGOAL (REPEAT_DETERM1 o tac));
+
+(*Repeatedly solve the first possible subgoal using tac. *)
+fun REPEAT_FIRST tac = REPEAT1 (FIRSTGOAL (REPEAT1 o tac));
+fun REPEAT_DETERM_FIRST tac = REPEAT_DETERM1 (FIRSTGOAL (REPEAT_DETERM1 o tac));
+
+(*For n subgoals, tries to apply tac to n,...1  *)
+fun TRYALL tac = ALLGOALS (TRY o tac);
+
+
+(*Make a tactic for subgoal i, if there is one.  *)
+fun CSUBGOAL goalfun i st =
+  (case SOME (Thm.cprem_of st i) handle THM _ => NONE of
+    SOME goal => goalfun (goal, i) st
+  | NONE => Seq.empty);
+
+fun SUBGOAL goalfun =
+  CSUBGOAL (fn (goal, i) => goalfun (Thm.term_of goal, i));
+
+(*Returns all states that have changed in subgoal i, counted from the LAST
+  subgoal.  For stac, for example.*)
+fun CHANGED_GOAL tac i st =
+    let val np = Thm.nprems_of st
+        val d = np-i                 (*distance from END*)
+        val t = Thm.term_of (Thm.cprem_of st i)
+        fun diff st' =
+            Thm.nprems_of st' - d <= 0   (*the subgoal no longer exists*)
+            orelse
+             not (Pattern.aeconv (t, Thm.term_of (Thm.cprem_of st' (Thm.nprems_of st' - d))))
+    in  Seq.filter diff (tac i st)  end
+    handle Subscript => Seq.empty  (*no subgoal i*);
+
+fun (tac1 THEN_ALL_NEW tac2) i st =
+  st |> (tac1 i THEN (fn st' => Seq.INTERVAL tac2 i (i + nprems_of st' - nprems_of st) st'));
+
+(*repeatedly dig into any emerging subgoals*)
+fun REPEAT_ALL_NEW tac =
+  tac THEN_ALL_NEW (TRY o (fn i => REPEAT_ALL_NEW tac i));
+
+
+(*Strips assumptions in goal yielding  ( [x1,...,xm], [H1,...,Hn], B )
+    H1,...,Hn are the hypotheses;  x1...xm are variants of the parameters.
+  Main difference from strip_assums concerns parameters:
+    it replaces the bound variables by free variables.  *)
+fun strip_context_aux (params, Hs, Const("==>", _) $ H $ B) =
+        strip_context_aux (params, H::Hs, B)
+  | strip_context_aux (params, Hs, Const("all",_)$Abs(a,T,t)) =
+        let val (b,u) = Syntax.variant_abs(a,T,t)
+        in  strip_context_aux ((b,T)::params, Hs, u)  end
+  | strip_context_aux (params, Hs, B) = (rev params, rev Hs, B);
+
+fun strip_context A = strip_context_aux ([],[],A);
+
+
+(**** METAHYPS -- tactical for using hypotheses as meta-level assumptions
+       METAHYPS (fn prems => tac prems) i
+
+converts subgoal i, of the form !!x1...xm. [| A1;...;An] ==> A into a new
+proof state A==>A, supplying A1,...,An as meta-level assumptions (in
+"prems").  The parameters x1,...,xm become free variables.  If the
+resulting proof state is [| B1;...;Bk] ==> C (possibly assuming A1,...,An)
+then it is lifted back into the original context, yielding k subgoals.
+
+Replaces unknowns in the context by Frees having the prefix METAHYP_
+New unknowns in [| B1;...;Bk] ==> C are lifted over x1,...,xm.
+DOES NOT HANDLE TYPE UNKNOWNS.
+****)
+
+local
+
+  (*Left-to-right replacements: ctpairs = [...,(vi,ti),...].
+    Instantiates distinct free variables by terms of same type.*)
+  fun free_instantiate ctpairs =
+    forall_elim_list (map snd ctpairs) o forall_intr_list (map fst ctpairs);
+
+  fun free_of s ((a, i), T) =
+    Free (s ^ (case i of 0 => a | _ => a ^ "_" ^ string_of_int i), T)
+
+  fun mk_inst v = (Var v, free_of "METAHYP1_" v)
+in
+
+(*Common code for METAHYPS and metahyps_thms*)
+fun metahyps_split_prem prem =
+  let (*find all vars in the hyps -- should find tvars also!*)
+      val hyps_vars = fold Term.add_vars (Logic.strip_assums_hyp prem) []
+      val insts = map mk_inst hyps_vars
+      (*replace the hyps_vars by Frees*)
+      val prem' = subst_atomic insts prem
+      val (params,hyps,concl) = strip_context prem'
+  in (insts,params,hyps,concl)  end;
+
+fun metahyps_aux_tac tacf (prem,gno) state =
+  let val (insts,params,hyps,concl) = metahyps_split_prem prem
+      val maxidx = Thm.maxidx_of state
+      val cterm = Thm.cterm_of (Thm.theory_of_thm state)
+      val chyps = map cterm hyps
+      val hypths = map assume chyps
+      val subprems = map (Thm.forall_elim_vars 0) hypths
+      val fparams = map Free params
+      val cparams = map cterm fparams
+      fun swap_ctpair (t,u) = (cterm u, cterm t)
+      (*Subgoal variables: make Free; lift type over params*)
+      fun mk_subgoal_inst concl_vars (v, T) =
+          if member (op =) concl_vars (v, T)
+          then ((v, T), true, free_of "METAHYP2_" (v, T))
+          else ((v, T), false, free_of "METAHYP2_" (v, map #2 params ---> T))
+      (*Instantiate subgoal vars by Free applied to params*)
+      fun mk_ctpair (v, in_concl, u) =
+          if in_concl then (cterm (Var v), cterm u)
+          else (cterm (Var v), cterm (list_comb (u, fparams)))
+      (*Restore Vars with higher type and index*)
+      fun mk_subgoal_swap_ctpair (((a, i), T), in_concl, u as Free (_, U)) =
+          if in_concl then (cterm u, cterm (Var ((a, i), T)))
+          else (cterm u, cterm (Var ((a, i + maxidx), U)))
+      (*Embed B in the original context of params and hyps*)
+      fun embed B = list_all_free (params, Logic.list_implies (hyps, B))
+      (*Strip the context using elimination rules*)
+      fun elim Bhyp = implies_elim_list (forall_elim_list cparams Bhyp) hypths
+      (*A form of lifting that discharges assumptions.*)
+      fun relift st =
+        let val prop = Thm.prop_of st
+            val subgoal_vars = (*Vars introduced in the subgoals*)
+              fold Term.add_vars (Logic.strip_imp_prems prop) []
+            and concl_vars = Term.add_vars (Logic.strip_imp_concl prop) []
+            val subgoal_insts = map (mk_subgoal_inst concl_vars) subgoal_vars
+            val st' = Thm.instantiate ([], map mk_ctpair subgoal_insts) st
+            val emBs = map (cterm o embed) (prems_of st')
+            val Cth  = implies_elim_list st' (map (elim o assume) emBs)
+        in  (*restore the unknowns to the hypotheses*)
+            free_instantiate (map swap_ctpair insts @
+                              map mk_subgoal_swap_ctpair subgoal_insts)
+                (*discharge assumptions from state in same order*)
+                (implies_intr_list emBs
+                  (forall_intr_list cparams (implies_intr_list chyps Cth)))
+        end
+      (*function to replace the current subgoal*)
+      fun next st = Thm.bicompose false (false, relift st, nprems_of st) gno state
+  in Seq.maps next (tacf subprems (trivial (cterm concl))) end;
+
+end;
+
+(*Returns the theorem list that METAHYPS would supply to its tactic*)
+fun metahyps_thms i state =
+  let val prem = Logic.nth_prem (i, Thm.prop_of state)
+      and cterm = cterm_of (Thm.theory_of_thm state)
+      val (_,_,hyps,_) = metahyps_split_prem prem
+  in SOME (map (Thm.forall_elim_vars 0 o Thm.assume o cterm) hyps) end
+  handle TERM ("nth_prem", [A]) => NONE;
+
+local
+
+fun print_vars_terms thy (n,thm) =
+  let
+    fun typed ty = " has type: " ^ Syntax.string_of_typ_global thy ty;
+    fun find_vars thy (Const (c, ty)) =
+          if null (Term.add_tvarsT ty []) then I
+          else insert (op =) (c ^ typed ty)
+      | find_vars thy (Var (xi, ty)) = insert (op =) (Term.string_of_vname xi ^ typed ty)
+      | find_vars _ (Free _) = I
+      | find_vars _ (Bound _) = I
+      | find_vars thy (Abs (_, _, t)) = find_vars thy t
+      | find_vars thy (t1 $ t2) =
+          find_vars thy t1 #> find_vars thy t1;
+    val prem = Logic.nth_prem (n, Thm.prop_of thm)
+    val tms = find_vars thy prem []
+  in
+    (warning "Found schematic vars in assumptions:"; warning (cat_lines tms))
+  end;
+
+in
+
+fun METAHYPS tacf n thm = SUBGOAL (metahyps_aux_tac tacf) n thm
+  handle THM("assume: variables",_,_) => (print_vars_terms (theory_of_thm thm) (n,thm); Seq.empty)
+
+end;
+
+(*Makes a tactic whose effect on a state is given by thmfun: thm->thm seq.*)
+fun PRIMSEQ thmfun st =  thmfun st handle THM _ => Seq.empty;
+
+(*Makes a tactic whose effect on a state is given by thmfun: thm->thm.*)
+fun PRIMITIVE thmfun = PRIMSEQ (Seq.single o thmfun);
+
+(*Inverse (more or less) of PRIMITIVE*)
+fun SINGLE tacf = Option.map fst o Seq.pull o tacf
+
+(*Conversions as tactics*)
+fun CONVERSION cv i st = Seq.single (Conv.gconv_rule cv i st)
+  handle THM _ => Seq.empty
+    | CTERM _ => Seq.empty
+    | TERM _ => Seq.empty
+    | TYPE _ => Seq.empty;
+
+end;
+
+open Tactical;
--- a/src/Pure/tctical.ML	Fri Jul 24 11:55:34 2009 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,524 +0,0 @@
-(*  Title:      Pure/tctical.ML
-    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
-
-Tacticals.
-*)
-
-infix 1 THEN THEN' THEN_ALL_NEW;
-infix 0 ORELSE APPEND INTLEAVE ORELSE' APPEND' INTLEAVE';
-infix 0 THEN_ELSE;
-
-signature TACTICAL =
-sig
-  type tactic = thm -> thm Seq.seq
-  val THEN: tactic * tactic -> tactic
-  val ORELSE: tactic * tactic -> tactic
-  val APPEND: tactic * tactic -> tactic
-  val INTLEAVE: tactic * tactic -> tactic
-  val THEN_ELSE: tactic * (tactic*tactic) -> tactic
-  val THEN': ('a -> tactic) * ('a -> tactic) -> 'a -> tactic
-  val ORELSE': ('a -> tactic) * ('a -> tactic) -> 'a -> tactic
-  val APPEND': ('a -> tactic) * ('a -> tactic) -> 'a -> tactic
-  val INTLEAVE': ('a -> tactic) * ('a -> tactic) -> 'a -> tactic
-  val all_tac: tactic
-  val no_tac: tactic
-  val DETERM: tactic -> tactic
-  val COND: (thm -> bool) -> tactic -> tactic -> tactic
-  val TRY: tactic -> tactic
-  val EVERY: tactic list -> tactic
-  val EVERY': ('a -> tactic) list -> 'a -> tactic
-  val EVERY1: (int -> tactic) list -> tactic
-  val FIRST: tactic list -> tactic
-  val FIRST': ('a -> tactic) list -> 'a -> tactic
-  val FIRST1: (int -> tactic) list -> tactic
-  val RANGE: (int -> tactic) list -> int -> tactic
-  val print_tac: string -> tactic
-  val pause_tac: tactic
-  val trace_REPEAT: bool ref
-  val suppress_tracing: bool ref
-  val tracify: bool ref -> tactic -> tactic
-  val traced_tac: (thm -> (thm * thm Seq.seq) option) -> tactic
-  val DETERM_UNTIL: (thm -> bool) -> tactic -> tactic
-  val REPEAT_DETERM_N: int -> tactic -> tactic
-  val REPEAT_DETERM: tactic -> tactic
-  val REPEAT: tactic -> tactic
-  val REPEAT_DETERM1: tactic -> tactic
-  val REPEAT1: tactic -> tactic
-  val FILTER: (thm -> bool) -> tactic -> tactic
-  val CHANGED: tactic -> tactic
-  val CHANGED_PROP: tactic -> tactic
-  val ALLGOALS: (int -> tactic) -> tactic
-  val SOMEGOAL: (int -> tactic) -> tactic
-  val FIRSTGOAL: (int -> tactic) -> tactic
-  val REPEAT_SOME: (int -> tactic) -> tactic
-  val REPEAT_DETERM_SOME: (int -> tactic) -> tactic
-  val REPEAT_FIRST: (int -> tactic) -> tactic
-  val REPEAT_DETERM_FIRST: (int -> tactic) -> tactic
-  val TRYALL: (int -> tactic) -> tactic
-  val CSUBGOAL: ((cterm * int) -> tactic) -> int -> tactic
-  val SUBGOAL: ((term * int) -> tactic) -> int -> tactic
-  val CHANGED_GOAL: (int -> tactic) -> int -> tactic
-  val THEN_ALL_NEW: (int -> tactic) * (int -> tactic) -> int -> tactic
-  val REPEAT_ALL_NEW: (int -> tactic) -> int -> tactic
-  val strip_context: term -> (string * typ) list * term list * term
-  val metahyps_thms: int -> thm -> thm list option
-  val METAHYPS: (thm list -> tactic) -> int -> tactic
-  val PRIMSEQ: (thm -> thm Seq.seq) -> tactic
-  val PRIMITIVE: (thm -> thm) -> tactic
-  val SINGLE: tactic -> thm -> thm option
-  val CONVERSION: conv -> int -> tactic
-end;
-
-structure Tactical : TACTICAL =
-struct
-
-(**** Tactics ****)
-
-(*A tactic maps a proof tree to a sequence of proof trees:
-    if length of sequence = 0 then the tactic does not apply;
-    if length > 1 then backtracking on the alternatives can occur.*)
-
-type tactic = thm -> thm Seq.seq;
-
-
-(*** LCF-style tacticals ***)
-
-(*the tactical THEN performs one tactic followed by another*)
-fun (tac1 THEN tac2) st = Seq.maps tac2 (tac1 st);
-
-
-(*The tactical ORELSE uses the first tactic that returns a nonempty sequence.
-  Like in LCF, ORELSE commits to either tac1 or tac2 immediately.
-  Does not backtrack to tac2 if tac1 was initially chosen. *)
-fun (tac1 ORELSE tac2) st =
-    case Seq.pull(tac1 st) of
-        NONE       => tac2 st
-      | sequencecell => Seq.make(fn()=> sequencecell);
-
-
-(*The tactical APPEND combines the results of two tactics.
-  Like ORELSE, but allows backtracking on both tac1 and tac2.
-  The tactic tac2 is not applied until needed.*)
-fun (tac1 APPEND tac2) st =
-  Seq.append (tac1 st) (Seq.make(fn()=> Seq.pull (tac2 st)));
-
-(*Like APPEND, but interleaves results of tac1 and tac2.*)
-fun (tac1 INTLEAVE tac2) st =
-    Seq.interleave(tac1 st,
-                        Seq.make(fn()=> Seq.pull (tac2 st)));
-
-(*Conditional tactic.
-        tac1 ORELSE tac2 = tac1 THEN_ELSE (all_tac, tac2)
-        tac1 THEN tac2   = tac1 THEN_ELSE (tac2, no_tac)
-*)
-fun (tac THEN_ELSE (tac1, tac2)) st =
-    case Seq.pull(tac st) of
-        NONE    => tac2 st                                   (*failed; try tactic 2*)
-      | seqcell => Seq.maps tac1 (Seq.make(fn()=> seqcell)); (*succeeded; use tactic 1*)
-
-
-(*Versions for combining tactic-valued functions, as in
-     SOMEGOAL (resolve_tac rls THEN' assume_tac) *)
-fun (tac1 THEN' tac2) x = tac1 x THEN tac2 x;
-fun (tac1 ORELSE' tac2) x = tac1 x ORELSE tac2 x;
-fun (tac1 APPEND' tac2) x = tac1 x APPEND tac2 x;
-fun (tac1 INTLEAVE' tac2) x = tac1 x INTLEAVE tac2 x;
-
-(*passes all proofs through unchanged;  identity of THEN*)
-fun all_tac st = Seq.single st;
-
-(*passes no proofs through;  identity of ORELSE and APPEND*)
-fun no_tac st  = Seq.empty;
-
-
-(*Make a tactic deterministic by chopping the tail of the proof sequence*)
-fun DETERM tac = Seq.DETERM tac;
-
-(*Conditional tactical: testfun controls which tactic to use next.
-  Beware: due to eager evaluation, both thentac and elsetac are evaluated.*)
-fun COND testfun thenf elsef = (fn prf =>
-    if testfun prf then  thenf prf   else  elsef prf);
-
-(*Do the tactic or else do nothing*)
-fun TRY tac = tac ORELSE all_tac;
-
-(*** List-oriented tactics ***)
-
-local
-  (*This version of EVERY avoids backtracking over repeated states*)
-
-  fun EVY (trail, []) st =
-        Seq.make (fn()=> SOME(st,
-                        Seq.make (fn()=> Seq.pull (evyBack trail))))
-    | EVY (trail, tac::tacs) st =
-          case Seq.pull(tac st) of
-              NONE    => evyBack trail              (*failed: backtrack*)
-            | SOME(st',q) => EVY ((st',q,tacs)::trail, tacs) st'
-  and evyBack [] = Seq.empty (*no alternatives*)
-    | evyBack ((st',q,tacs)::trail) =
-          case Seq.pull q of
-              NONE        => evyBack trail
-            | SOME(st,q') => if Thm.eq_thm (st',st)
-                             then evyBack ((st',q',tacs)::trail)
-                             else EVY ((st,q',tacs)::trail, tacs) st
-in
-
-(* EVERY [tac1,...,tacn]   equals    tac1 THEN ... THEN tacn   *)
-fun EVERY tacs = EVY ([], tacs);
-end;
-
-
-(* EVERY' [tac1,...,tacn] i  equals    tac1 i THEN ... THEN tacn i   *)
-fun EVERY' tacs i = EVERY (map (fn f => f i) tacs);
-
-(*Apply every tactic to 1*)
-fun EVERY1 tacs = EVERY' tacs 1;
-
-(* FIRST [tac1,...,tacn]   equals    tac1 ORELSE ... ORELSE tacn   *)
-fun FIRST tacs = fold_rev (curry op ORELSE) tacs no_tac;
-
-(* FIRST' [tac1,...,tacn] i  equals    tac1 i ORELSE ... ORELSE tacn i   *)
-fun FIRST' tacs = fold_rev (curry op ORELSE') tacs (K no_tac);
-
-(*Apply first tactic to 1*)
-fun FIRST1 tacs = FIRST' tacs 1;
-
-(*Apply tactics on consecutive subgoals*)
-fun RANGE [] _ = all_tac
-  | RANGE (tac :: tacs) i = RANGE tacs (i + 1) THEN tac i;
-
-
-(*** Tracing tactics ***)
-
-(*Print the current proof state and pass it on.*)
-fun print_tac msg st =
- (tracing (msg ^ "\n" ^
-    Pretty.string_of (Pretty.chunks
-      (Display_Goal.pretty_goals_without_context (! Display_Goal.goals_limit) st)));
-  Seq.single st);
-
-(*Pause until a line is typed -- if non-empty then fail. *)
-fun pause_tac st =
-  (tracing "** Press RETURN to continue:";
-   if TextIO.inputLine TextIO.stdIn = SOME "\n" then Seq.single st
-   else (tracing "Goodbye";  Seq.empty));
-
-exception TRACE_EXIT of thm
-and TRACE_QUIT;
-
-(*Tracing flags*)
-val trace_REPEAT= ref false
-and suppress_tracing = ref false;
-
-(*Handle all tracing commands for current state and tactic *)
-fun exec_trace_command flag (tac, st) =
-   case TextIO.inputLine TextIO.stdIn of
-       SOME "\n" => tac st
-     | SOME "f\n" => Seq.empty
-     | SOME "o\n" => (flag:=false;  tac st)
-     | SOME "s\n" => (suppress_tracing:=true;  tac st)
-     | SOME "x\n" => (tracing "Exiting now";  raise (TRACE_EXIT st))
-     | SOME "quit\n" => raise TRACE_QUIT
-     | _     => (tracing
-"Type RETURN to continue or...\n\
-\     f    - to fail here\n\
-\     o    - to switch tracing off\n\
-\     s    - to suppress tracing until next entry to a tactical\n\
-\     x    - to exit at this point\n\
-\     quit - to abort this tracing run\n\
-\** Well? "     ;  exec_trace_command flag (tac, st));
-
-
-(*Extract from a tactic, a thm->thm seq function that handles tracing*)
-fun tracify flag tac st =
-  if !flag andalso not (!suppress_tracing) then
-    (tracing (Pretty.string_of (Pretty.chunks
-        (Display_Goal.pretty_goals_without_context (! Display_Goal.goals_limit) st @
-          [Pretty.str "** Press RETURN to continue:"])));
-     exec_trace_command flag (tac, st))
-  else tac st;
-
-(*Create a tactic whose outcome is given by seqf, handling TRACE_EXIT*)
-fun traced_tac seqf st =
-    (suppress_tracing := false;
-     Seq.make (fn()=> seqf st
-                         handle TRACE_EXIT st' => SOME(st', Seq.empty)));
-
-
-(*Deterministic DO..UNTIL: only retains the first outcome; tail recursive.
-  Forces repitition until predicate on state is fulfilled.*)
-fun DETERM_UNTIL p tac =
-let val tac = tracify trace_REPEAT tac
-    fun drep st = if p st then SOME (st, Seq.empty)
-                          else (case Seq.pull(tac st) of
-                                  NONE        => NONE
-                                | SOME(st',_) => drep st')
-in  traced_tac drep  end;
-
-(*Deterministic REPEAT: only retains the first outcome;
-  uses less space than REPEAT; tail recursive.
-  If non-negative, n bounds the number of repetitions.*)
-fun REPEAT_DETERM_N n tac =
-  let val tac = tracify trace_REPEAT tac
-      fun drep 0 st = SOME(st, Seq.empty)
-        | drep n st =
-           (case Seq.pull(tac st) of
-                NONE       => SOME(st, Seq.empty)
-              | SOME(st',_) => drep (n-1) st')
-  in  traced_tac (drep n)  end;
-
-(*Allows any number of repetitions*)
-val REPEAT_DETERM = REPEAT_DETERM_N ~1;
-
-(*General REPEAT: maintains a stack of alternatives; tail recursive*)
-fun REPEAT tac =
-  let val tac = tracify trace_REPEAT tac
-      fun rep qs st =
-        case Seq.pull(tac st) of
-            NONE       => SOME(st, Seq.make(fn()=> repq qs))
-          | SOME(st',q) => rep (q::qs) st'
-      and repq [] = NONE
-        | repq(q::qs) = case Seq.pull q of
-            NONE       => repq qs
-          | SOME(st,q) => rep (q::qs) st
-  in  traced_tac (rep [])  end;
-
-(*Repeat 1 or more times*)
-fun REPEAT_DETERM1 tac = DETERM tac THEN REPEAT_DETERM tac;
-fun REPEAT1 tac = tac THEN REPEAT tac;
-
-
-(** Filtering tacticals **)
-
-fun FILTER pred tac st = Seq.filter pred (tac st);
-
-(*Accept only next states that change the theorem somehow*)
-fun CHANGED tac st =
-  let fun diff st' = not (Thm.eq_thm (st, st'));
-  in Seq.filter diff (tac st) end;
-
-(*Accept only next states that change the theorem's prop field
-  (changes to signature, hyps, etc. don't count)*)
-fun CHANGED_PROP tac st =
-  let fun diff st' = not (Thm.eq_thm_prop (st, st'));
-  in Seq.filter diff (tac st) end;
-
-
-(*** Tacticals based on subgoal numbering ***)
-
-(*For n subgoals, performs tac(n) THEN ... THEN tac(1)
-  Essential to work backwards since tac(i) may add/delete subgoals at i. *)
-fun ALLGOALS tac st =
-  let fun doall 0 = all_tac
-        | doall n = tac(n) THEN doall(n-1)
-  in  doall(nprems_of st)st  end;
-
-(*For n subgoals, performs tac(n) ORELSE ... ORELSE tac(1)  *)
-fun SOMEGOAL tac st =
-  let fun find 0 = no_tac
-        | find n = tac(n) ORELSE find(n-1)
-  in  find(nprems_of st)st  end;
-
-(*For n subgoals, performs tac(1) ORELSE ... ORELSE tac(n).
-  More appropriate than SOMEGOAL in some cases.*)
-fun FIRSTGOAL tac st =
-  let fun find (i,n) = if i>n then no_tac else  tac(i) ORELSE find (i+1,n)
-  in  find(1, nprems_of st)st  end;
-
-(*Repeatedly solve some using tac. *)
-fun REPEAT_SOME tac = REPEAT1 (SOMEGOAL (REPEAT1 o tac));
-fun REPEAT_DETERM_SOME tac = REPEAT_DETERM1 (SOMEGOAL (REPEAT_DETERM1 o tac));
-
-(*Repeatedly solve the first possible subgoal using tac. *)
-fun REPEAT_FIRST tac = REPEAT1 (FIRSTGOAL (REPEAT1 o tac));
-fun REPEAT_DETERM_FIRST tac = REPEAT_DETERM1 (FIRSTGOAL (REPEAT_DETERM1 o tac));
-
-(*For n subgoals, tries to apply tac to n,...1  *)
-fun TRYALL tac = ALLGOALS (TRY o tac);
-
-
-(*Make a tactic for subgoal i, if there is one.  *)
-fun CSUBGOAL goalfun i st =
-  (case SOME (Thm.cprem_of st i) handle THM _ => NONE of
-    SOME goal => goalfun (goal, i) st
-  | NONE => Seq.empty);
-
-fun SUBGOAL goalfun =
-  CSUBGOAL (fn (goal, i) => goalfun (Thm.term_of goal, i));
-
-(*Returns all states that have changed in subgoal i, counted from the LAST
-  subgoal.  For stac, for example.*)
-fun CHANGED_GOAL tac i st =
-    let val np = Thm.nprems_of st
-        val d = np-i                 (*distance from END*)
-        val t = Thm.term_of (Thm.cprem_of st i)
-        fun diff st' =
-            Thm.nprems_of st' - d <= 0   (*the subgoal no longer exists*)
-            orelse
-             not (Pattern.aeconv (t, Thm.term_of (Thm.cprem_of st' (Thm.nprems_of st' - d))))
-    in  Seq.filter diff (tac i st)  end
-    handle Subscript => Seq.empty  (*no subgoal i*);
-
-fun (tac1 THEN_ALL_NEW tac2) i st =
-  st |> (tac1 i THEN (fn st' => Seq.INTERVAL tac2 i (i + nprems_of st' - nprems_of st) st'));
-
-(*repeatedly dig into any emerging subgoals*)
-fun REPEAT_ALL_NEW tac =
-  tac THEN_ALL_NEW (TRY o (fn i => REPEAT_ALL_NEW tac i));
-
-
-(*Strips assumptions in goal yielding  ( [x1,...,xm], [H1,...,Hn], B )
-    H1,...,Hn are the hypotheses;  x1...xm are variants of the parameters.
-  Main difference from strip_assums concerns parameters:
-    it replaces the bound variables by free variables.  *)
-fun strip_context_aux (params, Hs, Const("==>", _) $ H $ B) =
-        strip_context_aux (params, H::Hs, B)
-  | strip_context_aux (params, Hs, Const("all",_)$Abs(a,T,t)) =
-        let val (b,u) = Syntax.variant_abs(a,T,t)
-        in  strip_context_aux ((b,T)::params, Hs, u)  end
-  | strip_context_aux (params, Hs, B) = (rev params, rev Hs, B);
-
-fun strip_context A = strip_context_aux ([],[],A);
-
-
-(**** METAHYPS -- tactical for using hypotheses as meta-level assumptions
-       METAHYPS (fn prems => tac prems) i
-
-converts subgoal i, of the form !!x1...xm. [| A1;...;An] ==> A into a new
-proof state A==>A, supplying A1,...,An as meta-level assumptions (in
-"prems").  The parameters x1,...,xm become free variables.  If the
-resulting proof state is [| B1;...;Bk] ==> C (possibly assuming A1,...,An)
-then it is lifted back into the original context, yielding k subgoals.
-
-Replaces unknowns in the context by Frees having the prefix METAHYP_
-New unknowns in [| B1;...;Bk] ==> C are lifted over x1,...,xm.
-DOES NOT HANDLE TYPE UNKNOWNS.
-****)
-
-local
-
-  (*Left-to-right replacements: ctpairs = [...,(vi,ti),...].
-    Instantiates distinct free variables by terms of same type.*)
-  fun free_instantiate ctpairs =
-    forall_elim_list (map snd ctpairs) o forall_intr_list (map fst ctpairs);
-
-  fun free_of s ((a, i), T) =
-    Free (s ^ (case i of 0 => a | _ => a ^ "_" ^ string_of_int i), T)
-
-  fun mk_inst v = (Var v, free_of "METAHYP1_" v)
-in
-
-(*Common code for METAHYPS and metahyps_thms*)
-fun metahyps_split_prem prem =
-  let (*find all vars in the hyps -- should find tvars also!*)
-      val hyps_vars = fold Term.add_vars (Logic.strip_assums_hyp prem) []
-      val insts = map mk_inst hyps_vars
-      (*replace the hyps_vars by Frees*)
-      val prem' = subst_atomic insts prem
-      val (params,hyps,concl) = strip_context prem'
-  in (insts,params,hyps,concl)  end;
-
-fun metahyps_aux_tac tacf (prem,gno) state =
-  let val (insts,params,hyps,concl) = metahyps_split_prem prem
-      val maxidx = Thm.maxidx_of state
-      val cterm = Thm.cterm_of (Thm.theory_of_thm state)
-      val chyps = map cterm hyps
-      val hypths = map assume chyps
-      val subprems = map (Thm.forall_elim_vars 0) hypths
-      val fparams = map Free params
-      val cparams = map cterm fparams
-      fun swap_ctpair (t,u) = (cterm u, cterm t)
-      (*Subgoal variables: make Free; lift type over params*)
-      fun mk_subgoal_inst concl_vars (v, T) =
-          if member (op =) concl_vars (v, T)
-          then ((v, T), true, free_of "METAHYP2_" (v, T))
-          else ((v, T), false, free_of "METAHYP2_" (v, map #2 params ---> T))
-      (*Instantiate subgoal vars by Free applied to params*)
-      fun mk_ctpair (v, in_concl, u) =
-          if in_concl then (cterm (Var v), cterm u)
-          else (cterm (Var v), cterm (list_comb (u, fparams)))
-      (*Restore Vars with higher type and index*)
-      fun mk_subgoal_swap_ctpair (((a, i), T), in_concl, u as Free (_, U)) =
-          if in_concl then (cterm u, cterm (Var ((a, i), T)))
-          else (cterm u, cterm (Var ((a, i + maxidx), U)))
-      (*Embed B in the original context of params and hyps*)
-      fun embed B = list_all_free (params, Logic.list_implies (hyps, B))
-      (*Strip the context using elimination rules*)
-      fun elim Bhyp = implies_elim_list (forall_elim_list cparams Bhyp) hypths
-      (*A form of lifting that discharges assumptions.*)
-      fun relift st =
-        let val prop = Thm.prop_of st
-            val subgoal_vars = (*Vars introduced in the subgoals*)
-              fold Term.add_vars (Logic.strip_imp_prems prop) []
-            and concl_vars = Term.add_vars (Logic.strip_imp_concl prop) []
-            val subgoal_insts = map (mk_subgoal_inst concl_vars) subgoal_vars
-            val st' = Thm.instantiate ([], map mk_ctpair subgoal_insts) st
-            val emBs = map (cterm o embed) (prems_of st')
-            val Cth  = implies_elim_list st' (map (elim o assume) emBs)
-        in  (*restore the unknowns to the hypotheses*)
-            free_instantiate (map swap_ctpair insts @
-                              map mk_subgoal_swap_ctpair subgoal_insts)
-                (*discharge assumptions from state in same order*)
-                (implies_intr_list emBs
-                  (forall_intr_list cparams (implies_intr_list chyps Cth)))
-        end
-      (*function to replace the current subgoal*)
-      fun next st = Thm.bicompose false (false, relift st, nprems_of st) gno state
-  in Seq.maps next (tacf subprems (trivial (cterm concl))) end;
-
-end;
-
-(*Returns the theorem list that METAHYPS would supply to its tactic*)
-fun metahyps_thms i state =
-  let val prem = Logic.nth_prem (i, Thm.prop_of state)
-      and cterm = cterm_of (Thm.theory_of_thm state)
-      val (_,_,hyps,_) = metahyps_split_prem prem
-  in SOME (map (Thm.forall_elim_vars 0 o Thm.assume o cterm) hyps) end
-  handle TERM ("nth_prem", [A]) => NONE;
-
-local
-
-fun print_vars_terms thy (n,thm) =
-  let
-    fun typed ty = " has type: " ^ Syntax.string_of_typ_global thy ty;
-    fun find_vars thy (Const (c, ty)) =
-          if null (Term.add_tvarsT ty []) then I
-          else insert (op =) (c ^ typed ty)
-      | find_vars thy (Var (xi, ty)) = insert (op =) (Term.string_of_vname xi ^ typed ty)
-      | find_vars _ (Free _) = I
-      | find_vars _ (Bound _) = I
-      | find_vars thy (Abs (_, _, t)) = find_vars thy t
-      | find_vars thy (t1 $ t2) =
-          find_vars thy t1 #> find_vars thy t1;
-    val prem = Logic.nth_prem (n, Thm.prop_of thm)
-    val tms = find_vars thy prem []
-  in
-    (warning "Found schematic vars in assumptions:"; warning (cat_lines tms))
-  end;
-
-in
-
-fun METAHYPS tacf n thm = SUBGOAL (metahyps_aux_tac tacf) n thm
-  handle THM("assume: variables",_,_) => (print_vars_terms (theory_of_thm thm) (n,thm); Seq.empty)
-
-end;
-
-(*Makes a tactic whose effect on a state is given by thmfun: thm->thm seq.*)
-fun PRIMSEQ thmfun st =  thmfun st handle THM _ => Seq.empty;
-
-(*Makes a tactic whose effect on a state is given by thmfun: thm->thm.*)
-fun PRIMITIVE thmfun = PRIMSEQ (Seq.single o thmfun);
-
-(*Inverse (more or less) of PRIMITIVE*)
-fun SINGLE tacf = Option.map fst o Seq.pull o tacf
-
-(*Conversions as tactics*)
-fun CONVERSION cv i st = Seq.single (Conv.gconv_rule cv i st)
-  handle THM _ => Seq.empty
-    | CTERM _ => Seq.empty
-    | TERM _ => Seq.empty
-    | TYPE _ => Seq.empty;
-
-end;
-
-open Tactical;