src/Pure/drule.ML

   sig
   structure Thm : THM
   local open Thm  in
   val asm_rl: thm
   val assume_ax: theory -> string -> thm
+  val cterm_fun: (term -> term) -> (cterm -> cterm)
   val COMP: thm * thm -> thm
   val compose: thm * int * thm -> thm list
-  val cterm_instantiate: (Sign.cterm*Sign.cterm)list -> thm -> thm
+  val cterm_instantiate: (cterm*cterm)list -> thm -> thm
   val cut_rl: thm
-  val equal_abs_elim: Sign.cterm  -> thm -> thm
-  val equal_abs_elim_list: Sign.cterm list -> thm -> thm
+  val equal_abs_elim: cterm  -> thm -> thm
+  val equal_abs_elim_list: cterm list -> thm -> thm
   val eq_sg: Sign.sg * Sign.sg -> bool
   val eq_thm: thm * thm -> bool
   val eq_thm_sg: thm * thm -> bool
-  val flexpair_abs_elim_list: Sign.cterm list -> thm -> thm
-  val forall_intr_list: Sign.cterm list -> thm -> thm
+  val flexpair_abs_elim_list: cterm list -> thm -> thm
+  val forall_intr_list: cterm list -> thm -> thm
   val forall_intr_frees: thm -> thm
-  val forall_elim_list: Sign.cterm list -> thm -> thm
+  val forall_elim_list: cterm list -> thm -> thm
   val forall_elim_var: int -> thm -> thm
   val forall_elim_vars: int -> thm -> thm
   val implies_elim_list: thm -> thm list -> thm
-  val implies_intr_list: Sign.cterm list -> thm -> thm
+  val implies_intr_list: cterm list -> thm -> thm
   val MRL: thm list list * thm list -> thm list
   val MRS: thm list * thm -> thm
-  val print_cterm: Sign.cterm -> unit
-  val print_ctyp: Sign.ctyp -> unit
+  val pprint_cterm: cterm -> pprint_args -> unit
+  val pprint_ctyp: ctyp -> pprint_args -> unit
+  val pprint_sg: Sign.sg -> pprint_args -> unit
+  val pprint_theory: theory -> pprint_args -> unit
+  val pprint_thm: thm -> pprint_args -> unit
+  val pretty_thm: thm -> Sign.Syntax.Pretty.T
+  val print_cterm: cterm -> unit
+  val print_ctyp: ctyp -> unit
   val print_goals: int -> thm -> unit
   val print_goals_ref: (int -> thm -> unit) ref
   val print_sg: Sign.sg -> unit
   val print_theory: theory -> unit
-  val pprint_sg: Sign.sg -> pprint_args -> unit
-  val pprint_theory: theory -> pprint_args -> unit
-  val pretty_thm: thm -> Sign.Syntax.Pretty.T
   val print_thm: thm -> unit
   val prth: thm -> thm
   val prthq: thm Sequence.seq -> thm Sequence.seq
   val prths: thm list -> thm list
+  val read_ctyp: Sign.sg -> string -> ctyp
   val read_instantiate: (string*string)list -> thm -> thm
   val read_instantiate_sg: Sign.sg -> (string*string)list -> thm -> thm
+  val read_insts: 
+          Sign.sg -> (indexname -> typ option) * (indexname -> sort option)
+                  -> (indexname -> typ option) * (indexname -> sort option)
+                  -> (string*string)list
+                  -> (indexname*ctyp)list * (cterm*cterm)list
   val reflexive_thm: thm
   val revcut_rl: thm
   val rewrite_goal_rule: bool*bool -> (meta_simpset -> thm -> thm option)
         -> meta_simpset -> int -> thm -> thm
   val rewrite_goals_rule: thm list -> thm -> thm

   val RL: thm list * thm list -> thm list
   val RLN: thm list * (int * thm list) -> thm list
   val show_hyps: bool ref
   val size_of_thm: thm -> int
   val standard: thm -> thm
+  val string_of_cterm: cterm -> string
+  val string_of_ctyp: ctyp -> string
   val string_of_thm: thm -> string
   val symmetric_thm: thm
-  val pprint_thm: thm -> pprint_args -> unit
   val transitive_thm: thm
   val triv_forall_equality: thm
   val types_sorts: thm -> (indexname-> typ option) * (indexname-> sort option)
   val zero_var_indexes: thm -> thm
   end

 local open Thm
 in
 
 (**** More derived rules and operations on theorems ****)
 
-(*** Find the type (sort) associated with a (T)Var or (T)Free in a term 
-     Used for establishing default types (of variables) and sorts (of
-     type variables) when reading another term.
-     Index -1 indicates that a (T)Free rather than a (T)Var is wanted.
-***)
-
-fun types_sorts thm =
-    let val {prop,hyps,...} = rep_thm thm;
-	val big = list_comb(prop,hyps); (* bogus term! *)
-	val vars = map dest_Var (term_vars big);
-	val frees = map dest_Free (term_frees big);
-	val tvars = term_tvars big;
-	val tfrees = term_tfrees big;
-	fun typ(a,i) = if i<0 then assoc(frees,a) else assoc(vars,(a,i));
-	fun sort(a,i) = if i<0 then assoc(tfrees,a) else assoc(tvars,(a,i));
-    in (typ,sort) end;
-
-(** Standardization of rules **)
-
-(*Generalization over a list of variables, IGNORING bad ones*)
-fun forall_intr_list [] th = th
-  | forall_intr_list (y::ys) th =
-	let val gth = forall_intr_list ys th
-	in  forall_intr y gth   handle THM _ =>  gth  end;
-
-(*Generalization over all suitable Free variables*)
-fun forall_intr_frees th =
-    let val {prop,sign,...} = rep_thm th
-    in  forall_intr_list
-         (map (Sign.cterm_of sign) (sort atless (term_frees prop))) 
-         th
-    end;
-
-(*Replace outermost quantified variable by Var of given index.
-    Could clash with Vars already present.*)
-fun forall_elim_var i th = 
-    let val {prop,sign,...} = rep_thm th
-    in case prop of
-	  Const("all",_) $ Abs(a,T,_) =>
-	      forall_elim (Sign.cterm_of sign (Var((a,i), T)))  th
-	| _ => raise THM("forall_elim_var", i, [th])
-    end;
-
-(*Repeat forall_elim_var until all outer quantifiers are removed*)
-fun forall_elim_vars i th = 
-    forall_elim_vars i (forall_elim_var i th)
-	handle THM _ => th;
-
-(*Specialization over a list of cterms*)
-fun forall_elim_list cts th = foldr (uncurry forall_elim) (rev cts, th);
-
-(* maps [A1,...,An], B   to   [| A1;...;An |] ==> B  *)
-fun implies_intr_list cAs th = foldr (uncurry implies_intr) (cAs,th);
-
-(* maps [| A1;...;An |] ==> B and [A1,...,An]   to   B *)
-fun implies_elim_list impth ths = foldl (uncurry implies_elim) (impth,ths);
-
-(*Reset Var indexes to zero, renaming to preserve distinctness*)
-fun zero_var_indexes th = 
-    let val {prop,sign,...} = rep_thm th;
-        val vars = term_vars prop
-        val bs = foldl add_new_id ([], map (fn Var((a,_),_)=>a) vars)
-	val inrs = add_term_tvars(prop,[]);
-	val nms' = rev(foldl add_new_id ([], map (#1 o #1) inrs));
-	val tye = map (fn ((v,rs),a) => (v, TVar((a,0),rs))) (inrs ~~ nms')
-	val ctye = map (fn (v,T) => (v,Sign.ctyp_of sign T)) tye;
-	fun varpairs([],[]) = []
-	  | varpairs((var as Var(v,T)) :: vars, b::bs) =
-		let val T' = typ_subst_TVars tye T
-		in (Sign.cterm_of sign (Var(v,T')),
-		    Sign.cterm_of sign (Var((b,0),T'))) :: varpairs(vars,bs)
-		end
-	  | varpairs _ = raise TERM("varpairs", []);
-    in instantiate (ctye, varpairs(vars,rev bs)) th end;
-
-
-(*Standard form of object-rule: no hypotheses, Frees, or outer quantifiers;
-    all generality expressed by Vars having index 0.*)
-fun standard th =
-    let val {maxidx,...} = rep_thm th
-    in  varifyT (zero_var_indexes (forall_elim_vars(maxidx+1) 
-                         (forall_intr_frees(implies_intr_hyps th))))
-    end;
-
-(*Assume a new formula, read following the same conventions as axioms. 
-  Generalizes over Free variables,
-  creates the assumption, and then strips quantifiers.
-  Example is [| ALL x:?A. ?P(x) |] ==> [| ?P(?a) |]
-	     [ !(A,P,a)[| ALL x:A. P(x) |] ==> [| P(a) |] ]    *)
-fun assume_ax thy sP =
-    let val sign = sign_of thy
-	val prop = Logic.close_form (Sign.term_of (Sign.read_cterm sign
-			 (sP, propT)))
-    in forall_elim_vars 0 (assume (Sign.cterm_of sign prop))  end;
-
-(*Resolution: exactly one resolvent must be produced.*) 
-fun tha RSN (i,thb) =
-  case Sequence.chop (2, biresolution false [(false,tha)] i thb) of
-      ([th],_) => th
-    | ([],_)   => raise THM("RSN: no unifiers", i, [tha,thb])
-    |      _   => raise THM("RSN: multiple unifiers", i, [tha,thb]);
-
-(*resolution: P==>Q, Q==>R gives P==>R. *)
-fun tha RS thb = tha RSN (1,thb);
-
-(*For joining lists of rules*)
-fun thas RLN (i,thbs) = 
-  let val resolve = biresolution false (map (pair false) thas) i
-      fun resb thb = Sequence.list_of_s (resolve thb) handle THM _ => []
-  in  flat (map resb thbs)  end;
-
-fun thas RL thbs = thas RLN (1,thbs);
-
-(*Resolve a list of rules against bottom_rl from right to left;
-  makes proof trees*)
-fun rls MRS bottom_rl = 
-  let fun rs_aux i [] = bottom_rl
-	| rs_aux i (rl::rls) = rl RSN (i, rs_aux (i+1) rls)
-  in  rs_aux 1 rls  end;
-
-(*As above, but for rule lists*)
-fun rlss MRL bottom_rls = 
-  let fun rs_aux i [] = bottom_rls
-	| rs_aux i (rls::rlss) = rls RLN (i, rs_aux (i+1) rlss)
-  in  rs_aux 1 rlss  end;
-
-(*compose Q and [...,Qi,Q(i+1),...]==>R to [...,Q(i+1),...]==>R 
-  with no lifting or renaming!  Q may contain ==> or meta-quants
-  ALWAYS deletes premise i *)
-fun compose(tha,i,thb) = 
-    Sequence.list_of_s (bicompose false (false,tha,0) i thb);
-
-(*compose Q and [Q1,Q2,...,Qk]==>R to [Q2,...,Qk]==>R getting unique result*)
-fun tha COMP thb =
-    case compose(tha,1,thb) of
-        [th] => th  
-      | _ =>   raise THM("COMP", 1, [tha,thb]);
-
-(*Instantiate theorem th, reading instantiations under signature sg*)
-fun read_instantiate_sg sg sinsts th =
-    let val ts = types_sorts th;
-        val instpair = Sign.read_insts sg ts ts sinsts
-    in  instantiate instpair th  end;
-
-(*Instantiate theorem th, reading instantiations under theory of th*)
-fun read_instantiate sinsts th =
-    read_instantiate_sg (#sign (rep_thm th)) sinsts th;
-
-
-(*Left-to-right replacements: tpairs = [...,(vi,ti),...].
-  Instantiates distinct Vars by terms, inferring type instantiations. *)
-local
-  fun add_types ((ct,cu), (sign,tye)) =
-    let val {sign=signt, t=t, T= T, ...} = Sign.rep_cterm ct
-        and {sign=signu, t=u, T= U, ...} = Sign.rep_cterm cu
-        val sign' = Sign.merge(sign, Sign.merge(signt, signu))
-	val tye' = Type.unify (#tsig(Sign.rep_sg sign')) ((T,U), tye)
-	  handle Type.TUNIFY => raise TYPE("add_types", [T,U], [t,u])
-    in  (sign', tye')  end;
-in
-fun cterm_instantiate ctpairs0 th = 
-  let val (sign,tye) = foldr add_types (ctpairs0, (#sign(rep_thm th),[]))
-      val tsig = #tsig(Sign.rep_sg sign);
-      fun instT(ct,cu) = let val inst = subst_TVars tye
-			 in (Sign.cfun inst ct, Sign.cfun inst cu) end
-      fun ctyp2 (ix,T) = (ix, Sign.ctyp_of sign T)
-  in  instantiate (map ctyp2 tye, map instT ctpairs0) th  end
-  handle TERM _ => 
-           raise THM("cterm_instantiate: incompatible signatures",0,[th])
-       | TYPE _ => raise THM("cterm_instantiate: types", 0, [th])
-end;
+fun cterm_fun f ct =
+ let val {sign,t,...} = rep_cterm ct in cterm_of sign (f t) end;
+
+fun read_ctyp sign = ctyp_of sign o Sign.read_typ(sign, K None);
+
+
+(** reading of instantiations **)
+
+fun indexname cs = case Syntax.scan_varname cs of (v,[]) => v
+        | _ => error("Lexical error in variable name " ^ quote (implode cs));
+
+fun absent ixn =
+  error("No such variable in term: " ^ Syntax.string_of_vname ixn);
+
+fun inst_failure ixn =
+  error("Instantiation of " ^ Syntax.string_of_vname ixn ^ " fails");
+
+fun read_insts sign (rtypes,rsorts) (types,sorts) insts =
+let val {tsig,...} = Sign.rep_sg sign
+    fun split([],tvs,vs) = (tvs,vs)
+      | split((sv,st)::l,tvs,vs) = (case explode sv of
+                  "'"::cs => split(l,(indexname cs,st)::tvs,vs)
+                | cs => split(l,tvs,(indexname cs,st)::vs));
+    val (tvs,vs) = split(insts,[],[]);
+    fun readT((a,i),st) =
+        let val ixn = ("'" ^ a,i);
+            val S = case rsorts ixn of Some S => S | None => absent ixn;
+            val T = Sign.read_typ (sign,sorts) st;
+        in if Type.typ_instance(tsig,T,TVar(ixn,S)) then (ixn,T)
+           else inst_failure ixn
+        end
+    val tye = map readT tvs;
+    fun add_cterm ((cts,tye), (ixn,st)) =
+        let val T = case rtypes ixn of
+                      Some T => typ_subst_TVars tye T
+                    | None => absent ixn;
+            val (ct,tye2) = read_def_cterm (sign,types,sorts) (st,T);
+            val cv = cterm_of sign (Var(ixn,typ_subst_TVars tye2 T))
+        in ((cv,ct)::cts,tye2 @ tye) end
+    val (cterms,tye') = foldl add_cterm (([],tye), vs);
+in (map (fn (ixn,T) => (ixn,ctyp_of sign T)) tye', cterms) end;
 
 
 (*** Printing of theorems ***)
 
 (*If false, hypotheses are printed as dots*)

 
 (*Print and return a list of theorems, separated by blank lines. *)
 fun prths ths = (print_list_ln print_thm ths; ths);
 
 (*Other printing commands*)
-val print_cterm = writeln o Sign.string_of_cterm;
-val print_ctyp = writeln o Sign.string_of_ctyp;
+fun pprint_ctyp cT = 
+ let val {sign,T} = rep_ctyp cT in  Sign.pprint_typ sign T  end;
+
+fun string_of_ctyp cT = 
+ let val {sign,T} = rep_ctyp cT in  Sign.string_of_typ sign T  end;
+
+val print_ctyp = writeln o string_of_ctyp;
+
+fun pprint_cterm ct = 
+ let val {sign,t,...} = rep_cterm ct in  Sign.pprint_term sign t  end;
+
+fun string_of_cterm ct = 
+ let val {sign,t,...} = rep_cterm ct in  Sign.string_of_term sign t  end;
+
+val print_cterm = writeln o string_of_cterm;
+
 fun pretty_sg sg = 
   Pretty.lst ("{", "}") (map (Pretty.str o !) (#stamps (Sign.rep_sg sg)));
 
 val pprint_sg = Pretty.pprint o pretty_sg;
 

 end;
 
 (*"hook" for user interfaces: allows print_goals to be replaced*)
 val print_goals_ref = ref print_goals;
 
+(*** Find the type (sort) associated with a (T)Var or (T)Free in a term 
+     Used for establishing default types (of variables) and sorts (of
+     type variables) when reading another term.
+     Index -1 indicates that a (T)Free rather than a (T)Var is wanted.
+***)
+
+fun types_sorts thm =
+    let val {prop,hyps,...} = rep_thm thm;
+	val big = list_comb(prop,hyps); (* bogus term! *)
+	val vars = map dest_Var (term_vars big);
+	val frees = map dest_Free (term_frees big);
+	val tvars = term_tvars big;
+	val tfrees = term_tfrees big;
+	fun typ(a,i) = if i<0 then assoc(frees,a) else assoc(vars,(a,i));
+	fun sort(a,i) = if i<0 then assoc(tfrees,a) else assoc(tvars,(a,i));
+    in (typ,sort) end;
+
+(** Standardization of rules **)
+
+(*Generalization over a list of variables, IGNORING bad ones*)
+fun forall_intr_list [] th = th
+  | forall_intr_list (y::ys) th =
+	let val gth = forall_intr_list ys th
+	in  forall_intr y gth   handle THM _ =>  gth  end;
+
+(*Generalization over all suitable Free variables*)
+fun forall_intr_frees th =
+    let val {prop,sign,...} = rep_thm th
+    in  forall_intr_list
+         (map (cterm_of sign) (sort atless (term_frees prop))) 
+         th
+    end;
+
+(*Replace outermost quantified variable by Var of given index.
+    Could clash with Vars already present.*)
+fun forall_elim_var i th = 
+    let val {prop,sign,...} = rep_thm th
+    in case prop of
+	  Const("all",_) $ Abs(a,T,_) =>
+	      forall_elim (cterm_of sign (Var((a,i), T)))  th
+	| _ => raise THM("forall_elim_var", i, [th])
+    end;
+
+(*Repeat forall_elim_var until all outer quantifiers are removed*)
+fun forall_elim_vars i th = 
+    forall_elim_vars i (forall_elim_var i th)
+	handle THM _ => th;
+
+(*Specialization over a list of cterms*)
+fun forall_elim_list cts th = foldr (uncurry forall_elim) (rev cts, th);
+
+(* maps [A1,...,An], B   to   [| A1;...;An |] ==> B  *)
+fun implies_intr_list cAs th = foldr (uncurry implies_intr) (cAs,th);
+
+(* maps [| A1;...;An |] ==> B and [A1,...,An]   to   B *)
+fun implies_elim_list impth ths = foldl (uncurry implies_elim) (impth,ths);
+
+(*Reset Var indexes to zero, renaming to preserve distinctness*)
+fun zero_var_indexes th = 
+    let val {prop,sign,...} = rep_thm th;
+        val vars = term_vars prop
+        val bs = foldl add_new_id ([], map (fn Var((a,_),_)=>a) vars)
+	val inrs = add_term_tvars(prop,[]);
+	val nms' = rev(foldl add_new_id ([], map (#1 o #1) inrs));
+	val tye = map (fn ((v,rs),a) => (v, TVar((a,0),rs))) (inrs ~~ nms')
+	val ctye = map (fn (v,T) => (v,ctyp_of sign T)) tye;
+	fun varpairs([],[]) = []
+	  | varpairs((var as Var(v,T)) :: vars, b::bs) =
+		let val T' = typ_subst_TVars tye T
+		in (cterm_of sign (Var(v,T')),
+		    cterm_of sign (Var((b,0),T'))) :: varpairs(vars,bs)
+		end
+	  | varpairs _ = raise TERM("varpairs", []);
+    in instantiate (ctye, varpairs(vars,rev bs)) th end;
+
+
+(*Standard form of object-rule: no hypotheses, Frees, or outer quantifiers;
+    all generality expressed by Vars having index 0.*)
+fun standard th =
+    let val {maxidx,...} = rep_thm th
+    in  varifyT (zero_var_indexes (forall_elim_vars(maxidx+1) 
+                         (forall_intr_frees(implies_intr_hyps th))))
+    end;
+
+(*Assume a new formula, read following the same conventions as axioms. 
+  Generalizes over Free variables,
+  creates the assumption, and then strips quantifiers.
+  Example is [| ALL x:?A. ?P(x) |] ==> [| ?P(?a) |]
+	     [ !(A,P,a)[| ALL x:A. P(x) |] ==> [| P(a) |] ]    *)
+fun assume_ax thy sP =
+    let val sign = sign_of thy
+	val prop = Logic.close_form (term_of (read_cterm sign
+			 (sP, propT)))
+    in forall_elim_vars 0 (assume (cterm_of sign prop))  end;
+
+(*Resolution: exactly one resolvent must be produced.*) 
+fun tha RSN (i,thb) =
+  case Sequence.chop (2, biresolution false [(false,tha)] i thb) of
+      ([th],_) => th
+    | ([],_)   => raise THM("RSN: no unifiers", i, [tha,thb])
+    |      _   => raise THM("RSN: multiple unifiers", i, [tha,thb]);
+
+(*resolution: P==>Q, Q==>R gives P==>R. *)
+fun tha RS thb = tha RSN (1,thb);
+
+(*For joining lists of rules*)
+fun thas RLN (i,thbs) = 
+  let val resolve = biresolution false (map (pair false) thas) i
+      fun resb thb = Sequence.list_of_s (resolve thb) handle THM _ => []
+  in  flat (map resb thbs)  end;
+
+fun thas RL thbs = thas RLN (1,thbs);
+
+(*Resolve a list of rules against bottom_rl from right to left;
+  makes proof trees*)
+fun rls MRS bottom_rl = 
+  let fun rs_aux i [] = bottom_rl
+	| rs_aux i (rl::rls) = rl RSN (i, rs_aux (i+1) rls)
+  in  rs_aux 1 rls  end;
+
+(*As above, but for rule lists*)
+fun rlss MRL bottom_rls = 
+  let fun rs_aux i [] = bottom_rls
+	| rs_aux i (rls::rlss) = rls RLN (i, rs_aux (i+1) rlss)
+  in  rs_aux 1 rlss  end;
+
+(*compose Q and [...,Qi,Q(i+1),...]==>R to [...,Q(i+1),...]==>R 
+  with no lifting or renaming!  Q may contain ==> or meta-quants
+  ALWAYS deletes premise i *)
+fun compose(tha,i,thb) = 
+    Sequence.list_of_s (bicompose false (false,tha,0) i thb);
+
+(*compose Q and [Q1,Q2,...,Qk]==>R to [Q2,...,Qk]==>R getting unique result*)
+fun tha COMP thb =
+    case compose(tha,1,thb) of
+        [th] => th  
+      | _ =>   raise THM("COMP", 1, [tha,thb]);
+
+(*Instantiate theorem th, reading instantiations under signature sg*)
+fun read_instantiate_sg sg sinsts th =
+    let val ts = types_sorts th;
+    in  instantiate (read_insts sg ts ts sinsts) th  end;
+
+(*Instantiate theorem th, reading instantiations under theory of th*)
+fun read_instantiate sinsts th =
+    read_instantiate_sg (#sign (rep_thm th)) sinsts th;
+
+
+(*Left-to-right replacements: tpairs = [...,(vi,ti),...].
+  Instantiates distinct Vars by terms, inferring type instantiations. *)
+local
+  fun add_types ((ct,cu), (sign,tye)) =
+    let val {sign=signt, t=t, T= T, ...} = rep_cterm ct
+        and {sign=signu, t=u, T= U, ...} = rep_cterm cu
+        val sign' = Sign.merge(sign, Sign.merge(signt, signu))
+	val tye' = Type.unify (#tsig(Sign.rep_sg sign')) ((T,U), tye)
+	  handle Type.TUNIFY => raise TYPE("add_types", [T,U], [t,u])
+    in  (sign', tye')  end;
+in
+fun cterm_instantiate ctpairs0 th = 
+  let val (sign,tye) = foldr add_types (ctpairs0, (#sign(rep_thm th),[]))
+      val tsig = #tsig(Sign.rep_sg sign);
+      fun instT(ct,cu) = let val inst = subst_TVars tye
+			 in (cterm_fun inst ct, cterm_fun inst cu) end
+      fun ctyp2 (ix,T) = (ix, ctyp_of sign T)
+  in  instantiate (map ctyp2 tye, map instT ctpairs0) th  end
+  handle TERM _ => 
+           raise THM("cterm_instantiate: incompatible signatures",0,[th])
+       | TYPE _ => raise THM("cterm_instantiate: types", 0, [th])
+end;
+
+
 (** theorem equality test is exported and used by BEST_FIRST **)
 
 (*equality of signatures means exact identity -- by ref equality*)
 fun eq_sg (sg1,sg2) = (#stamps(Sign.rep_sg sg1) = #stamps(Sign.rep_sg sg2));
 

 
 (*** Meta-Rewriting Rules ***)
 
 
 val reflexive_thm =
-  let val cx = Sign.cterm_of Sign.pure (Var(("x",0),TVar(("'a",0),["logic"])))
+  let val cx = cterm_of Sign.pure (Var(("x",0),TVar(("'a",0),["logic"])))
   in Thm.reflexive cx end;
 
 val symmetric_thm =
-  let val xy = Sign.read_cterm Sign.pure ("x::'a::logic == y",propT)
+  let val xy = read_cterm Sign.pure ("x::'a::logic == y",propT)
   in standard(Thm.implies_intr_hyps(Thm.symmetric(Thm.assume xy))) end;
 
 val transitive_thm =
-  let val xy = Sign.read_cterm Sign.pure ("x::'a::logic == y",propT)
-      val yz = Sign.read_cterm Sign.pure ("y::'a::logic == z",propT)
+  let val xy = read_cterm Sign.pure ("x::'a::logic == y",propT)
+      val yz = read_cterm Sign.pure ("y::'a::logic == z",propT)
       val xythm = Thm.assume xy and yzthm = Thm.assume yz
   in standard(Thm.implies_intr yz (Thm.transitive xythm yzthm)) end;
 
-(** Below, a "conversion" has type sign->term->thm **)
+(** Below, a "conversion" has type cterm -> thm **)
+
+val refl_cimplies = reflexive (cterm_of Sign.pure implies);
 
 (*In [A1,...,An]==>B, rewrite the selected A's only -- for rewrite_goals_tac*)
 (*Do not rewrite flex-flex pairs*)
-fun goals_conv pred cv sign = 
-  let val triv = reflexive o Sign.fake_cterm_of sign
-      fun gconv i t =
-        let val (A,B) = Logic.dest_implies t
-            val (thA,j) = case A of
-                  Const("=?=",_)$_$_ => (triv A,i)
-                | _ => (if pred i then cv sign A else triv A, i+1)
-	in  combination (combination (triv implies) thA) (gconv j B) end
-        handle TERM _ => triv t
+fun goals_conv pred cv = 
+  let fun gconv i ct =
+        let val (A,B) = Thm.dest_cimplies ct
+            val (thA,j) = case term_of A of
+                  Const("=?=",_)$_$_ => (reflexive A, i)
+                | _ => (if pred i then cv A else reflexive A, i+1)
+	in  combination (combination refl_cimplies thA) (gconv j B) end
+        handle TERM _ => reflexive ct
   in gconv 1 end;
 
 (*Use a conversion to transform a theorem*)
-fun fconv_rule cv th =
-  let val {sign,prop,...} = rep_thm th
-  in  equal_elim (cv sign prop) th  end;
+fun fconv_rule cv th = equal_elim (cv (cprop_of th)) th;
 
 (*rewriting conversion*)
-fun rew_conv mode prover mss sign t =
-  rewrite_cterm mode mss prover (Sign.fake_cterm_of sign t);
+fun rew_conv mode prover mss = rewrite_cterm mode mss prover;
 
 (*Rewrite a theorem*)
 fun rewrite_rule thms =
   fconv_rule (rew_conv (true,false) (K(K None)) (Thm.mss_of thms));
 

 
 (** Derived rules mainly for METAHYPS **)
 
 (*Given the term "a", takes (%x.t)==(%x.u) to t[a/x]==u[a/x]*)
 fun equal_abs_elim ca eqth =
-  let val {sign=signa, t=a, ...} = Sign.rep_cterm ca
+  let val {sign=signa, t=a, ...} = rep_cterm ca
       and combth = combination eqth (reflexive ca)
       val {sign,prop,...} = rep_thm eqth
       val (abst,absu) = Logic.dest_equals prop
-      val cterm = Sign.cterm_of (Sign.merge (sign,signa))
+      val cterm = cterm_of (Sign.merge (sign,signa))
   in  transitive (symmetric (beta_conversion (cterm (abst$a))))
            (transitive combth (beta_conversion (cterm (absu$a))))
   end
   handle THM _ => raise THM("equal_abs_elim", 0, [eqth]);
 

   open Logic
   val alpha = TVar(("'a",0), [])     (*  type ?'a::{}  *)
   fun err th = raise THM("flexpair_inst: ", 0, [th])
   fun flexpair_inst def th =
     let val {prop = Const _ $ t $ u,  sign,...} = rep_thm th
-	val cterm = Sign.cterm_of sign
+	val cterm = cterm_of sign
 	fun cvar a = cterm(Var((a,0),alpha))
 	val def' = cterm_instantiate [(cvar"t", cterm t), (cvar"u", cterm u)] 
 		   def
     in  equal_elim def' th
     end

 
 
 (*** Some useful meta-theorems ***)
 
 (*The rule V/V, obtains assumption solving for eresolve_tac*)
-val asm_rl = trivial(Sign.read_cterm Sign.pure ("PROP ?psi",propT));
+val asm_rl = trivial(read_cterm Sign.pure ("PROP ?psi",propT));
 
 (*Meta-level cut rule: [| V==>W; V |] ==> W *)
-val cut_rl = trivial(Sign.read_cterm Sign.pure 
+val cut_rl = trivial(read_cterm Sign.pure 
 	("PROP ?psi ==> PROP ?theta", propT));
 
 (*Generalized elim rule for one conclusion; cut_rl with reversed premises: 
      [| PROP V;  PROP V ==> PROP W |] ==> PROP W *)
 val revcut_rl =
-  let val V = Sign.read_cterm Sign.pure ("PROP V", propT)
-      and VW = Sign.read_cterm Sign.pure ("PROP V ==> PROP W", propT);
+  let val V = read_cterm Sign.pure ("PROP V", propT)
+      and VW = read_cterm Sign.pure ("PROP V ==> PROP W", propT);
   in  standard (implies_intr V 
 		(implies_intr VW
 		 (implies_elim (assume VW) (assume V))))
   end;
 
 (* (!!x. PROP ?V) == PROP ?V       Allows removal of redundant parameters*)
 val triv_forall_equality =
-  let val V  = Sign.read_cterm Sign.pure ("PROP V", propT)
-      and QV = Sign.read_cterm Sign.pure ("!!x::'a. PROP V", propT)
-      and x  = Sign.read_cterm Sign.pure ("x", TFree("'a",["logic"]));
+  let val V  = read_cterm Sign.pure ("PROP V", propT)
+      and QV = read_cterm Sign.pure ("!!x::'a. PROP V", propT)
+      and x  = read_cterm Sign.pure ("x", TFree("'a",["logic"]));
   in  standard (equal_intr (implies_intr QV (forall_elim x (assume QV)))
 		           (implies_intr V  (forall_intr x (assume V))))
   end;
 
 end