src/Pure/logic.ML
author wenzelm
Thu Oct 04 20:29:24 2007 +0200 (2007-10-04)
changeset 24848 5dbbd33c3236
parent 24258 2f399483535a
child 25939 ddea202704b4
permissions -rw-r--r--
replaced literal 'a by Name.aT;
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(*  Title:      Pure/logic.ML
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    ID:         $Id$
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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    Copyright   Cambridge University 1992
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Abstract syntax operations of the Pure meta-logic.
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*)
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signature LOGIC =
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sig
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  val dest_all: term -> typ * term
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  val mk_equals: term * term -> term
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  val dest_equals: term -> term * term
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  val mk_implies: term * term -> term
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  val dest_implies: term -> term * term
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  val list_implies: term list * term -> term
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  val strip_imp_prems: term -> term list
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  val strip_imp_concl: term -> term
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  val strip_prems: int * term list * term -> term list * term
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  val count_prems: term -> int
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  val nth_prem: int * term -> term
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  val true_prop: term
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  val conjunction: term
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  val mk_conjunction: term * term -> term
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  val mk_conjunction_list: term list -> term
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  val mk_conjunction_balanced: term list -> term
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  val dest_conjunction: term -> term * term
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  val dest_conjunction_list: term -> term list
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  val dest_conjunction_balanced: int -> term -> term list
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  val dest_conjunctions: term -> term list
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  val strip_horn: term -> term list * term
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  val mk_type: typ -> term
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  val dest_type: term -> typ
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  val type_map: (term -> term) -> typ -> typ
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  val const_of_class: class -> string
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  val class_of_const: string -> class
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  val mk_inclass: typ * class -> term
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  val dest_inclass: term -> typ * class
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  val name_classrel: string * string -> string
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  val mk_classrel: class * class -> term
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  val dest_classrel: term -> class * class
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  val name_arities: arity -> string list
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  val name_arity: string * sort list * class -> string
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  val mk_arities: arity -> term list
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  val dest_arity: term -> string * sort list * class
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  val protectC: term
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  val protect: term -> term
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  val unprotect: term -> term
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  val mk_term: term -> term
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  val dest_term: term -> term
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  val occs: term * term -> bool
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  val close_form: term -> term
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  val combound: term * int * int -> term
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  val rlist_abs: (string * typ) list * term -> term
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  val incr_indexes: typ list * int -> term -> term
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  val incr_tvar: int -> typ -> typ
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  val lift_abs: int -> term -> term -> term
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  val lift_all: int -> term -> term -> term
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  val strip_assums_hyp: term -> term list
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  val strip_assums_concl: term -> term
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  val strip_params: term -> (string * typ) list
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  val has_meta_prems: term -> bool
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  val flatten_params: int -> term -> term
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  val auto_rename: bool ref
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  val set_rename_prefix: string -> unit
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  val list_rename_params: string list * term -> term
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  val assum_pairs: int * term -> (term*term)list
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  val varifyT: typ -> typ
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  val unvarifyT: typ -> typ
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  val varify: term -> term
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  val unvarify: term -> term
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  val legacy_varifyT: typ -> typ
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  val legacy_unvarifyT: typ -> typ
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  val legacy_varify: term -> term
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  val legacy_unvarify: term -> term
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  val get_goal: term -> int -> term
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  val goal_params: term -> int -> term * term list
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  val prems_of_goal: term -> int -> term list
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  val concl_of_goal: term -> int -> term
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end;
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structure Logic : LOGIC =
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struct
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(*** Abstract syntax operations on the meta-connectives ***)
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(** all **)
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fun dest_all (Const ("all", Type ("fun", [Type ("fun", [T, _]), _])) $ A) = (T, A)
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  | dest_all t = raise TERM ("dest_all", [t]);
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(** equality **)
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fun mk_equals (t, u) = Term.equals (Term.fastype_of t) $ t $ u;
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fun dest_equals (Const ("==", _) $ t $ u) = (t, u)
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  | dest_equals t = raise TERM ("dest_equals", [t]);
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(** implies **)
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fun mk_implies (A, B) = implies $ A $ B;
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fun dest_implies (Const ("==>", _) $ A $ B) = (A, B)
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  | dest_implies A = raise TERM ("dest_implies", [A]);
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(** nested implications **)
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(* [A1,...,An], B  goes to  A1==>...An==>B  *)
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fun list_implies ([], B) = B
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  | list_implies (A::As, B) = implies $ A $ list_implies(As,B);
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(* A1==>...An==>B  goes to  [A1,...,An], where B is not an implication *)
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fun strip_imp_prems (Const("==>", _) $ A $ B) = A :: strip_imp_prems B
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  | strip_imp_prems _ = [];
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(* A1==>...An==>B  goes to B, where B is not an implication *)
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fun strip_imp_concl (Const("==>", _) $ A $ B) = strip_imp_concl B
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  | strip_imp_concl A = A : term;
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(*Strip and return premises: (i, [], A1==>...Ai==>B)
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    goes to   ([Ai, A(i-1),...,A1] , B)         (REVERSED)
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  if  i<0 or else i too big then raises  TERM*)
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fun strip_prems (0, As, B) = (As, B)
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  | strip_prems (i, As, Const("==>", _) $ A $ B) =
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        strip_prems (i-1, A::As, B)
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  | strip_prems (_, As, A) = raise TERM("strip_prems", A::As);
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(*Count premises -- quicker than (length o strip_prems) *)
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fun count_prems (Const ("==>", _) $ _ $ B) = 1 + count_prems B
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  | count_prems _ = 0;
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(*Select Ai from A1 ==>...Ai==>B*)
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fun nth_prem (1, Const ("==>", _) $ A $ _) = A
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  | nth_prem (i, Const ("==>", _) $ _ $ B) = nth_prem (i - 1, B)
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  | nth_prem (_, A) = raise TERM ("nth_prem", [A]);
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(*strip a proof state (Horn clause):
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  B1 ==> ... Bn ==> C   goes to   ([B1, ..., Bn], C)    *)
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fun strip_horn A = (strip_imp_prems A, strip_imp_concl A);
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(** conjunction **)
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val true_prop = Term.all propT $ Abs ("dummy", propT, mk_implies (Bound 0, Bound 0));
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val conjunction = Const ("ProtoPure.conjunction", propT --> propT --> propT);
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(*A && B*)
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fun mk_conjunction (A, B) = conjunction $ A $ B;
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(*A && B && C -- improper*)
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fun mk_conjunction_list [] = true_prop
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  | mk_conjunction_list ts = foldr1 mk_conjunction ts;
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(*(A && B) && (C && D) -- balanced*)
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fun mk_conjunction_balanced [] = true_prop
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  | mk_conjunction_balanced ts = BalancedTree.make mk_conjunction ts;
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(*A && B*)
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fun dest_conjunction (Const ("ProtoPure.conjunction", _) $ A $ B) = (A, B)
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  | dest_conjunction t = raise TERM ("dest_conjunction", [t]);
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(*A && B && C -- improper*)
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fun dest_conjunction_list t =
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  (case try dest_conjunction t of
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    NONE => [t]
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  | SOME (A, B) => A :: dest_conjunction_list B);
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(*(A && B) && (C && D) -- balanced*)
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fun dest_conjunction_balanced 0 _ = []
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  | dest_conjunction_balanced n t = BalancedTree.dest dest_conjunction n t;
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(*((A && B) && C) && D && E -- flat*)
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fun dest_conjunctions t =
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  (case try dest_conjunction t of
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    NONE => [t]
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  | SOME (A, B) => dest_conjunctions A @ dest_conjunctions B);
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(** types as terms **)
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fun mk_type ty = Const ("TYPE", Term.itselfT ty);
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fun dest_type (Const ("TYPE", Type ("itself", [ty]))) = ty
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  | dest_type t = raise TERM ("dest_type", [t]);
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fun type_map f = dest_type o f o mk_type;
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(** type classes **)
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(* const names *)
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val classN = "_class";
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val const_of_class = suffix classN;
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fun class_of_const c = unsuffix classN c
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  handle Fail _ => raise TERM ("class_of_const: bad name " ^ quote c, []);
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(* class constraints *)
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fun mk_inclass (ty, c) =
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  Const (const_of_class c, Term.itselfT ty --> propT) $ mk_type ty;
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fun dest_inclass (t as Const (c_class, _) $ ty) = (dest_type ty, class_of_const c_class)
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  | dest_inclass t = raise TERM ("dest_inclass", [t]);
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(* class relations *)
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fun name_classrel (c1, c2) =
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  NameSpace.base c1 ^ "_" ^ NameSpace.base c2;
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fun mk_classrel (c1, c2) = mk_inclass (Term.aT [c1], c2);
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fun dest_classrel tm =
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  (case dest_inclass tm of
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    (TVar (_, [c1]), c2) => (c1, c2)
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  | _ => raise TERM ("dest_classrel", [tm]));
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(* type arities *)
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fun name_arities (t, _, S) =
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  let val b = NameSpace.base t
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  in S |> map (fn c => NameSpace.base c ^ "_" ^ b) end;
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fun name_arity (t, dom, c) = hd (name_arities (t, dom, [c]));
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fun mk_arities (t, Ss, S) =
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  let val T = Type (t, ListPair.map TFree (Name.invents Name.context Name.aT (length Ss), Ss))
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  in map (fn c => mk_inclass (T, c)) S end;
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fun dest_arity tm =
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  let
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    fun err () = raise TERM ("dest_arity", [tm]);
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    val (ty, c) = dest_inclass tm;
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    val (t, tvars) =
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      (case ty of
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        Type (t, tys) => (t, map dest_TVar tys handle TYPE _ => err ())
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      | _ => err ());
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    val Ss =
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      if has_duplicates (eq_fst (op =)) tvars then err ()
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      else map snd tvars;
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  in (t, Ss, c) end;
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  (** protected propositions and embedded terms **)
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val protectC = Const ("prop", propT --> propT);
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fun protect t = protectC $ t;
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fun unprotect (Const ("prop", _) $ t) = t
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  | unprotect t = raise TERM ("unprotect", [t]);
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fun mk_term t = Const ("ProtoPure.term", Term.fastype_of t --> propT) $ t;
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fun dest_term (Const ("ProtoPure.term", _) $ t) = t
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  | dest_term t = raise TERM ("dest_term", [t]);
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(*** Low-level term operations ***)
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(*Does t occur in u?  Or is alpha-convertible to u?
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  The term t must contain no loose bound variables*)
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fun occs (t, u) = exists_subterm (fn s => t aconv s) u;
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(*Close up a formula over all free variables by quantification*)
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fun close_form A =
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  Term.list_all_free (rev (Term.add_frees A []), A);
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(*** Specialized operations for resolution... ***)
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(*computes t(Bound(n+k-1),...,Bound(n))  *)
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fun combound (t, n, k) =
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    if  k>0  then  combound (t,n+1,k-1) $ (Bound n)  else  t;
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(* ([xn,...,x1], t)   ======>   (x1,...,xn)t *)
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fun rlist_abs ([], body) = body
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  | rlist_abs ((a,T)::pairs, body) = rlist_abs(pairs, Abs(a, T, body));
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local exception SAME in
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fun incrT k =
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  let
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    fun incr (TVar ((a, i), S)) = TVar ((a, i + k), S)
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      | incr (Type (a, Ts)) = Type (a, incrs Ts)
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      | incr _ = raise SAME
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    and incrs (T :: Ts) =
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        (incr T :: (incrs Ts handle SAME => Ts)
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          handle SAME => T :: incrs Ts)
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      | incrs [] = raise SAME;
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  in incr end;
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(*For all variables in the term, increment indexnames and lift over the Us
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    result is ?Gidx(B.(lev+n-1),...,B.lev) where lev is abstraction level *)
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fun incr_indexes ([], 0) t = t
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  | incr_indexes (Ts, k) t =
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  let
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    val n = length Ts;
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    val incrT = if k = 0 then I else incrT k;
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    fun incr lev (Var ((x, i), T)) =
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          combound (Var ((x, i + k), Ts ---> (incrT T handle SAME => T)), lev, n)
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      | incr lev (Abs (x, T, body)) =
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          (Abs (x, incrT T, incr (lev + 1) body handle SAME => body)
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            handle SAME => Abs (x, T, incr (lev + 1) body))
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      | incr lev (t $ u) =
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          (incr lev t $ (incr lev u handle SAME => u)
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            handle SAME => t $ incr lev u)
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      | incr _ (Const (c, T)) = Const (c, incrT T)
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      | incr _ (Free (x, T)) = Free (x, incrT T)
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      | incr _ (t as Bound _) = t;
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  in incr 0 t handle SAME => t end;
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fun incr_tvar 0 T = T
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  | incr_tvar k T = incrT k T handle SAME => T;
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end;
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(* Lifting functions from subgoal and increment:
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    lift_abs operates on terms
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    lift_all operates on propositions *)
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fun lift_abs inc =
wenzelm@18029
   344
  let
wenzelm@18029
   345
    fun lift Ts (Const ("==>", _) $ _ $ B) t = lift Ts B t
wenzelm@18248
   346
      | lift Ts (Const ("all", _) $ Abs (a, T, B)) t = Abs (a, T, lift (T :: Ts) B t)
wenzelm@18029
   347
      | lift Ts _ t = incr_indexes (rev Ts, inc) t;
wenzelm@18029
   348
  in lift [] end;
wenzelm@18029
   349
wenzelm@18029
   350
fun lift_all inc =
wenzelm@18029
   351
  let
wenzelm@18029
   352
    fun lift Ts ((c as Const ("==>", _)) $ A $ B) t = c $ A $ lift Ts B t
wenzelm@18248
   353
      | lift Ts ((c as Const ("all", _)) $ Abs (a, T, B)) t = c $ Abs (a, T, lift (T :: Ts) B t)
wenzelm@18029
   354
      | lift Ts _ t = incr_indexes (rev Ts, inc) t;
wenzelm@18029
   355
  in lift [] end;
clasohm@0
   356
clasohm@0
   357
(*Strips assumptions in goal, yielding list of hypotheses.   *)
berghofe@21016
   358
fun strip_assums_hyp B =
berghofe@21016
   359
  let
berghofe@21016
   360
    fun strip Hs (Const ("==>", _) $ H $ B) = strip (H :: Hs) B
berghofe@21016
   361
      | strip Hs (Const ("all", _) $ Abs (a, T, t)) =
berghofe@21016
   362
          strip (map (incr_boundvars 1) Hs) t
berghofe@21016
   363
      | strip Hs B = rev Hs
berghofe@21016
   364
  in strip [] B end;
clasohm@0
   365
clasohm@0
   366
(*Strips assumptions in goal, yielding conclusion.   *)
clasohm@0
   367
fun strip_assums_concl (Const("==>", _) $ H $ B) = strip_assums_concl B
clasohm@0
   368
  | strip_assums_concl (Const("all",_)$Abs(a,T,t)) = strip_assums_concl t
clasohm@0
   369
  | strip_assums_concl B = B;
clasohm@0
   370
clasohm@0
   371
(*Make a list of all the parameters in a subgoal, even if nested*)
clasohm@0
   372
fun strip_params (Const("==>", _) $ H $ B) = strip_params B
clasohm@0
   373
  | strip_params (Const("all",_)$Abs(a,T,t)) = (a,T) :: strip_params t
clasohm@0
   374
  | strip_params B = [];
clasohm@0
   375
wenzelm@23597
   376
(*test for nested meta connectives in prems*)
wenzelm@23597
   377
val has_meta_prems =
wenzelm@9667
   378
  let
wenzelm@23597
   379
    fun is_meta (Const ("==", _) $ _ $ _) = true
wenzelm@23597
   380
      | is_meta (Const ("==>", _) $ _ $ _) = true
wenzelm@9667
   381
      | is_meta (Const ("all", _) $ _) = true
wenzelm@9667
   382
      | is_meta _ = false;
wenzelm@23597
   383
    fun ex_meta (Const ("==>", _) $ A $ B) = is_meta A orelse ex_meta B
wenzelm@23597
   384
      | ex_meta (Const ("all", _) $ Abs (_, _, B)) = ex_meta B
wenzelm@23597
   385
      | ex_meta _ = false;
wenzelm@23597
   386
  in ex_meta end;
wenzelm@9483
   387
clasohm@0
   388
(*Removes the parameters from a subgoal and renumber bvars in hypotheses,
wenzelm@9460
   389
    where j is the total number of parameters (precomputed)
clasohm@0
   390
  If n>0 then deletes assumption n. *)
wenzelm@9460
   391
fun remove_params j n A =
clasohm@0
   392
    if j=0 andalso n<=0 then A  (*nothing left to do...*)
clasohm@0
   393
    else case A of
wenzelm@9460
   394
        Const("==>", _) $ H $ B =>
wenzelm@9460
   395
          if n=1 then                           (remove_params j (n-1) B)
wenzelm@9460
   396
          else implies $ (incr_boundvars j H) $ (remove_params j (n-1) B)
clasohm@0
   397
      | Const("all",_)$Abs(a,T,t) => remove_params (j-1) n t
clasohm@0
   398
      | _ => if n>0 then raise TERM("remove_params", [A])
clasohm@0
   399
             else A;
clasohm@0
   400
clasohm@0
   401
(** Auto-renaming of parameters in subgoals **)
clasohm@0
   402
clasohm@0
   403
val auto_rename = ref false
clasohm@0
   404
and rename_prefix = ref "ka";
clasohm@0
   405
clasohm@0
   406
(*rename_prefix is not exported; it is set by this function.*)
clasohm@0
   407
fun set_rename_prefix a =
wenzelm@4693
   408
    if a<>"" andalso forall Symbol.is_letter (Symbol.explode a)
clasohm@0
   409
    then  (rename_prefix := a;  auto_rename := true)
clasohm@0
   410
    else  error"rename prefix must be nonempty and consist of letters";
clasohm@0
   411
clasohm@0
   412
(*Makes parameters in a goal have distinctive names (not guaranteed unique!)
clasohm@0
   413
  A name clash could cause the printer to rename bound vars;
clasohm@0
   414
    then res_inst_tac would not work properly.*)
clasohm@0
   415
fun rename_vars (a, []) = []
clasohm@0
   416
  | rename_vars (a, (_,T)::vars) =
wenzelm@12902
   417
        (a,T) :: rename_vars (Symbol.bump_string a, vars);
clasohm@0
   418
clasohm@0
   419
(*Move all parameters to the front of the subgoal, renaming them apart;
clasohm@0
   420
  if n>0 then deletes assumption n. *)
clasohm@0
   421
fun flatten_params n A =
clasohm@0
   422
    let val params = strip_params A;
wenzelm@9460
   423
        val vars = if !auto_rename
wenzelm@9460
   424
                   then rename_vars (!rename_prefix, params)
wenzelm@20078
   425
                   else ListPair.zip (Name.variant_list [] (map #1 params),
wenzelm@9460
   426
                                      map #2 params)
clasohm@0
   427
    in  list_all (vars, remove_params (length vars) n A)
clasohm@0
   428
    end;
clasohm@0
   429
clasohm@0
   430
(*Makes parameters in a goal have the names supplied by the list cs.*)
clasohm@0
   431
fun list_rename_params (cs, Const("==>", _) $ A $ B) =
clasohm@0
   432
      implies $ A $ list_rename_params (cs, B)
wenzelm@9460
   433
  | list_rename_params (c::cs, Const("all",_)$Abs(_,T,t)) =
clasohm@0
   434
      all T $ Abs(c, T, list_rename_params (cs, t))
clasohm@0
   435
  | list_rename_params (cs, B) = B;
clasohm@0
   436
wenzelm@19806
   437
(*** Treatment of "assume", "erule", etc. ***)
clasohm@0
   438
wenzelm@16879
   439
(*Strips assumptions in goal yielding
paulson@15451
   440
   HS = [Hn,...,H1],   params = [xm,...,x1], and B,
wenzelm@16879
   441
  where x1...xm are the parameters. This version (21.1.2005) REQUIRES
wenzelm@16879
   442
  the the parameters to be flattened, but it allows erule to work on
paulson@15451
   443
  assumptions of the form !!x. phi. Any !! after the outermost string
paulson@15451
   444
  will be regarded as belonging to the conclusion, and left untouched.
paulson@15454
   445
  Used ONLY by assum_pairs.
paulson@15454
   446
      Unless nasms<0, it can terminate the recursion early; that allows
paulson@15454
   447
  erule to work on assumptions of the form P==>Q.*)
paulson@15454
   448
fun strip_assums_imp (0, Hs, B) = (Hs, B)  (*recursion terminated by nasms*)
wenzelm@16879
   449
  | strip_assums_imp (nasms, Hs, Const("==>", _) $ H $ B) =
paulson@15454
   450
      strip_assums_imp (nasms-1, H::Hs, B)
paulson@15454
   451
  | strip_assums_imp (_, Hs, B) = (Hs, B); (*recursion terminated by B*)
paulson@15454
   452
clasohm@0
   453
paulson@15451
   454
(*Strips OUTER parameters only, unlike similar legacy versions.*)
paulson@15451
   455
fun strip_assums_all (params, Const("all",_)$Abs(a,T,t)) =
paulson@15451
   456
      strip_assums_all ((a,T)::params, t)
paulson@15451
   457
  | strip_assums_all (params, B) = (params, B);
clasohm@0
   458
clasohm@0
   459
(*Produces disagreement pairs, one for each assumption proof, in order.
clasohm@0
   460
  A is the first premise of the lifted rule, and thus has the form
paulson@15454
   461
    H1 ==> ... Hk ==> B   and the pairs are (H1,B),...,(Hk,B).
paulson@15454
   462
  nasms is the number of assumptions in the original subgoal, needed when B
paulson@15454
   463
    has the form B1 ==> B2: it stops B1 from being taken as an assumption. *)
paulson@15454
   464
fun assum_pairs(nasms,A) =
paulson@15451
   465
  let val (params, A') = strip_assums_all ([],A)
paulson@15454
   466
      val (Hs,B) = strip_assums_imp (nasms,[],A')
wenzelm@18938
   467
      fun abspar t = rlist_abs(params, t)
paulson@15451
   468
      val D = abspar B
paulson@15451
   469
      fun pairrev ([], pairs) = pairs
paulson@15451
   470
        | pairrev (H::Hs, pairs) = pairrev(Hs,  (abspar H, D) :: pairs)
paulson@15451
   471
  in  pairrev (Hs,[])
clasohm@0
   472
  end;
clasohm@0
   473
wenzelm@19806
   474
wenzelm@19806
   475
(* global schematic variables *)
wenzelm@19806
   476
wenzelm@19806
   477
fun bad_schematic xi = "Illegal schematic variable: " ^ quote (Term.string_of_vname xi);
wenzelm@19806
   478
fun bad_fixed x = "Illegal fixed variable: " ^ quote x;
wenzelm@19806
   479
wenzelm@19806
   480
fun varifyT ty = ty |> Term.map_atyps
wenzelm@19806
   481
  (fn TFree (a, S) => TVar ((a, 0), S)
wenzelm@19806
   482
    | TVar (ai, _) => raise TYPE (bad_schematic ai, [ty], []));
wenzelm@19806
   483
wenzelm@19806
   484
fun unvarifyT ty = ty |> Term.map_atyps
wenzelm@19806
   485
  (fn TVar ((a, 0), S) => TFree (a, S)
wenzelm@19806
   486
    | TVar (ai, _) => raise TYPE (bad_schematic ai, [ty], [])
wenzelm@19806
   487
    | TFree (a, _) => raise TYPE (bad_fixed a, [ty], []));
clasohm@0
   488
wenzelm@19806
   489
fun varify tm =
wenzelm@19806
   490
  tm |> Term.map_aterms
wenzelm@19806
   491
    (fn Free (x, T) => Var ((x, 0), T)
wenzelm@19806
   492
      | Var (xi, _) => raise TERM (bad_schematic xi, [tm])
wenzelm@19806
   493
      | t => t)
wenzelm@20548
   494
  |> Term.map_types varifyT
wenzelm@19879
   495
  handle TYPE (msg, _, _) => raise TERM (msg, [tm]);
wenzelm@19806
   496
wenzelm@19806
   497
fun unvarify tm =
wenzelm@19806
   498
  tm |> Term.map_aterms
wenzelm@19806
   499
    (fn Var ((x, 0), T) => Free (x, T)
wenzelm@19806
   500
      | Var (xi, _) => raise TERM (bad_schematic xi, [tm])
wenzelm@19806
   501
      | Free (x, _) => raise TERM (bad_fixed x, [tm])
wenzelm@19806
   502
      | t => t)
wenzelm@20548
   503
  |> Term.map_types unvarifyT
wenzelm@19879
   504
  handle TYPE (msg, _, _) => raise TERM (msg, [tm]);
wenzelm@19806
   505
wenzelm@19806
   506
val legacy_varifyT = Term.map_atyps (fn TFree (a, S) => TVar ((a, 0), S) | T => T);
wenzelm@19806
   507
val legacy_unvarifyT = Term.map_atyps (fn TVar ((a, 0), S) => TFree (a, S) | T => T);
wenzelm@19806
   508
wenzelm@19806
   509
val legacy_varify =
wenzelm@19806
   510
  Term.map_aterms (fn Free (x, T) => Var ((x, 0), T) | t => t) #>
wenzelm@20548
   511
  Term.map_types legacy_varifyT;
wenzelm@19806
   512
wenzelm@19806
   513
val legacy_unvarify =
wenzelm@19806
   514
  Term.map_aterms (fn Var ((x, 0), T) => Free (x, T) | t => t) #>
wenzelm@20548
   515
  Term.map_types legacy_unvarifyT;
lcp@546
   516
berghofe@13799
   517
wenzelm@16862
   518
(* goal states *)
wenzelm@16862
   519
wenzelm@16862
   520
fun get_goal st i = nth_prem (i, st)
wenzelm@16862
   521
  handle TERM _ => error "Goal number out of range";
berghofe@13799
   522
berghofe@13799
   523
(*reverses parameters for substitution*)
berghofe@13799
   524
fun goal_params st i =
berghofe@13799
   525
  let val gi = get_goal st i
berghofe@14137
   526
      val rfrees = map Free (rename_wrt_term gi (strip_params gi))
berghofe@13799
   527
  in (gi, rfrees) end;
berghofe@13799
   528
berghofe@13799
   529
fun concl_of_goal st i =
berghofe@13799
   530
  let val (gi, rfrees) = goal_params st i
berghofe@13799
   531
      val B = strip_assums_concl gi
berghofe@13799
   532
  in subst_bounds (rfrees, B) end;
berghofe@13799
   533
berghofe@13799
   534
fun prems_of_goal st i =
berghofe@13799
   535
  let val (gi, rfrees) = goal_params st i
berghofe@13799
   536
      val As = strip_assums_hyp gi
berghofe@13799
   537
  in map (fn A => subst_bounds (rfrees, A)) As end;
berghofe@13799
   538
clasohm@0
   539
end;