paulson@15481: (* -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- *) 
dixon@15538: (*  Title:      Provers/eqsubst.ML
paulson@15481:     Author:     Lucas Dixon, University of Edinburgh
paulson@15481:                 lucas.dixon@ed.ac.uk
dixon@15538:     Modified:   18 Feb 2005 - Lucas - 
paulson@15481:     Created:    29 Jan 2005
paulson@15481: *)
paulson@15481: (* -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- *) 
paulson@15481: (*  DESCRIPTION:
paulson@15481: 
paulson@15481:     A Tactic to perform a substiution using an equation.
paulson@15481: 
paulson@15481: *)
paulson@15481: (* -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- *)
paulson@15481: 
dixon@16004: 
dixon@16004: 
dixon@15538: (* Logic specific data stub *)
paulson@15481: signature EQRULE_DATA =
paulson@15481: sig
dixon@15538: 
paulson@15481:   (* to make a meta equality theorem in the current logic *)
paulson@15481:   val prep_meta_eq : thm -> thm list
dixon@15538: 
paulson@15481: end;
paulson@15481: 
dixon@15538: 
paulson@15481: (* the signature of an instance of the SQSUBST tactic *)
paulson@15481: signature EQSUBST_TAC = 
paulson@15481: sig
dixon@15538: 
dixon@15959:   exception eqsubst_occL_exp of 
dixon@15959:             string * (int list) * (Thm.thm list) * int * Thm.thm;
dixon@15959: 
dixon@16004: 
dixon@15550:   type match = 
dixon@15915:        ((Term.indexname * (Term.sort * Term.typ)) list (* type instantiations *)
dixon@15915:         * (Term.indexname * (Term.typ * Term.term)) list) (* term instantiations *)
dixon@15814:        * (string * Term.typ) list (* fake named type abs env *)
dixon@15814:        * (string * Term.typ) list (* type abs env *)
dixon@15814:        * Term.term (* outer term *)
dixon@15550: 
dixon@16004:   type searchinfo = 
dixon@16004:        Sign.sg (* sign for matching *)
dixon@16004:        * int (* maxidx *)
dixon@16004:        * BasicIsaFTerm.FcTerm (* focusterm to search under *)
dixon@16004: 
dixon@15538:   val prep_subst_in_asm :
dixon@16004:          int (* subgoal to subst in *)
dixon@15538:       -> Thm.thm (* target theorem with subgoals *)
dixon@15538:       -> int (* premise to subst in *)
dixon@15538:       -> (Thm.cterm list (* certified free var placeholders for vars *) 
dixon@15538:           * int (* premice no. to subst *)
dixon@15538:           * int (* number of assumptions of premice *)
dixon@15538:           * Thm.thm) (* premice as a new theorem for forward reasoning *)
dixon@16004:          * searchinfo (* search info: prem id etc *)
dixon@15538: 
dixon@15538:   val prep_subst_in_asms :
dixon@16004:          int (* subgoal to subst in *)
dixon@15538:       -> Thm.thm (* target theorem with subgoals *)
dixon@15538:       -> ((Thm.cterm list (* certified free var placeholders for vars *) 
dixon@15538:           * int (* premice no. to subst *)
dixon@15538:           * int (* number of assumptions of premice *)
dixon@15538:           * Thm.thm) (* premice as a new theorem for forward reasoning *)
dixon@16004:          * searchinfo) list
dixon@15538: 
dixon@15538:   val apply_subst_in_asm :
dixon@15538:       int (* subgoal *)
dixon@15538:       -> Thm.thm (* overall theorem *)
dixon@16004:       -> Thm.thm (* rule *)
dixon@15538:       -> (Thm.cterm list (* certified free var placeholders for vars *) 
dixon@15538:           * int (* assump no being subst *)
dixon@15538:           * int (* num of premises of asm *) 
dixon@15538:           * Thm.thm) (* premthm *)
dixon@16004:       * match
dixon@15538:       -> Thm.thm Seq.seq
dixon@15538: 
dixon@15538:   val prep_concl_subst :
dixon@16004:          int (* subgoal *)
dixon@15538:       -> Thm.thm (* overall goal theorem *)
dixon@16004:       -> (Thm.cterm list * Thm.thm) * searchinfo (* (cvfs, conclthm), matchf *)
dixon@15538: 
dixon@15538:   val apply_subst_in_concl :
dixon@15538:         int (* subgoal *)
dixon@15538:         -> Thm.thm (* thm with all goals *)
dixon@15538:         -> Thm.cterm list (* certified free var placeholders for vars *)
dixon@15538:            * Thm.thm  (* trivial thm of goal concl *)
dixon@15538:             (* possible matches/unifiers *)
dixon@15538:         -> Thm.thm (* rule *)
dixon@15550:         -> match
dixon@15538:         -> Thm.thm Seq.seq (* substituted goal *)
dixon@15538: 
dixon@16004:   (* basic notion of search *)
dixon@15814:   val searchf_tlr_unify_all : 
dixon@16004:       (searchinfo 
dixon@16004:        -> Term.term (* lhs *)
dixon@16004:        -> match Seq.seq Seq.seq)
dixon@15814:   val searchf_tlr_unify_valid : 
dixon@16004:       (searchinfo 
dixon@16004:        -> Term.term (* lhs *)
dixon@16004:        -> match Seq.seq Seq.seq)
dixon@15814: 
dixon@16004:   (* specialise search constructor for conclusion skipping occurnaces. *)
dixon@16004:      val skip_first_occs_search :
dixon@16004:         int -> ('a -> 'b -> 'c Seq.seq Seq.seq) -> 'a -> 'b -> 'c Seq.seq
dixon@16004:   (* specialised search constructor for assumptions using skips *)
dixon@16004:      val skip_first_asm_occs_search :
dixon@16004:         ('a -> 'b -> 'c Seq.seq Seq.seq) ->
dixon@16004:         'a -> int -> 'b -> 'c IsaPLib.skipseqT
dixon@16004: 
dixon@16004:   (* tactics and methods *)
dixon@15936:   val eqsubst_asm_meth : int list -> Thm.thm list -> Proof.method
dixon@16004:   val eqsubst_asm_tac : 
dixon@16004:       int list -> Thm.thm list -> int -> Thm.thm -> Thm.thm Seq.seq
dixon@15814:   val eqsubst_asm_tac' : 
dixon@16004:       (* search function with skips *)
dixon@16004:       (searchinfo -> int -> Term.term -> match IsaPLib.skipseqT) 
dixon@16004:       -> int (* skip to *)
dixon@16004:       -> Thm.thm (* rule *)
dixon@16004:       -> int (* subgoal number *)
dixon@16004:       -> Thm.thm (* tgt theorem with subgoals *)
dixon@16004:       -> Thm.thm Seq.seq (* new theorems *)
dixon@15538: 
dixon@15936:   val eqsubst_meth : int list -> Thm.thm list -> Proof.method
dixon@16004:   val eqsubst_tac : 
dixon@16004:       int list -> Thm.thm list -> int -> Thm.thm -> Thm.thm Seq.seq
dixon@15814:   val eqsubst_tac' : 
dixon@16004:       (searchinfo -> Term.term -> match Seq.seq) 
dixon@16004:       -> Thm.thm -> int -> Thm.thm -> Thm.thm Seq.seq
dixon@15538: 
dixon@15936:   val meth : (bool * int list) * Thm.thm list -> Proof.context -> Proof.method
paulson@15481:   val setup : (Theory.theory -> Theory.theory) list
paulson@15481: end;
paulson@15481: 
dixon@16004: 
paulson@15481: functor EQSubstTacFUN (structure EqRuleData : EQRULE_DATA) 
dixon@15538:   : EQSUBST_TAC
paulson@15481: = struct
paulson@15481: 
dixon@15915:   (* a type abriviation for match information *)
dixon@15550:   type match = 
dixon@15915:        ((Term.indexname * (Term.sort * Term.typ)) list (* type instantiations *)
dixon@15915:         * (Term.indexname * (Term.typ * Term.term)) list) (* term instantiations *)
dixon@15915:        * (string * Term.typ) list (* fake named type abs env *)
dixon@15915:        * (string * Term.typ) list (* type abs env *)
dixon@15915:        * Term.term (* outer term *)
dixon@15550: 
dixon@16004:   type searchinfo = 
dixon@16004:        Sign.sg (* sign for matching *)
dixon@16004:        * int (* maxidx *)
dixon@16004:        * BasicIsaFTerm.FcTerm (* focusterm to search under *)
dixon@15550: 
dixon@15538: (* FOR DEBUGGING...
dixon@15538: type trace_subst_errT = int (* subgoal *)
dixon@15538:         * Thm.thm (* thm with all goals *)
dixon@15538:         * (Thm.cterm list (* certified free var placeholders for vars *)
dixon@15538:            * Thm.thm)  (* trivial thm of goal concl *)
dixon@15538:             (* possible matches/unifiers *)
dixon@15538:         * Thm.thm (* rule *)
dixon@15538:         * (((Term.indexname * Term.typ) list (* type instantiations *)
dixon@15538:               * (Term.indexname * Term.term) list ) (* term instantiations *)
dixon@15538:              * (string * Term.typ) list (* Type abs env *)
dixon@15538:              * Term.term) (* outer term *);
dixon@15538: 
dixon@15538: val trace_subst_err = (ref NONE : trace_subst_errT option ref);
dixon@15538: val trace_subst_search = ref false;
dixon@15538: exception trace_subst_exp of trace_subst_errT;
dixon@15538:  *)
dixon@15538: 
dixon@15538: (* also defined in /HOL/Tools/inductive_codegen.ML, 
dixon@15538:    maybe move this to seq.ML ? *)
dixon@15538: infix 5 :->;
dixon@15538: fun s :-> f = Seq.flat (Seq.map f s);
dixon@15538: 
dixon@15814: (* search from top, left to right, then down *)
dixon@15814: fun search_tlr_all_f f ft = 
paulson@15481:     let
paulson@15481:       fun maux ft = 
paulson@15481:           let val t' = (IsaFTerm.focus_of_fcterm ft) 
dixon@15538:             (* val _ = 
dixon@15538:                 if !trace_subst_search then 
dixon@15538:                   (writeln ("Examining: " ^ (TermLib.string_of_term t'));
dixon@15538:                    TermLib.writeterm t'; ())
dixon@15538:                 else (); *)
paulson@15481:           in 
paulson@15481:           (case t' of 
dixon@15538:             (_ $ _) => Seq.append(maux (IsaFTerm.focus_left ft), 
dixon@15929:                        Seq.cons(f ft, 
paulson@15481:                                   maux (IsaFTerm.focus_right ft)))
dixon@15929:           | (Abs _) => Seq.cons(f ft, maux (IsaFTerm.focus_abs ft))
dixon@15929:           | leaf => Seq.single (f ft)) end
paulson@15481:     in maux ft end;
paulson@15481: 
dixon@15814: (* search from top, left to right, then down *)
dixon@15814: fun search_tlr_valid_f f ft = 
dixon@15814:     let
dixon@15814:       fun maux ft = 
dixon@15814:           let 
dixon@15814:             val hereseq = if IsaFTerm.valid_match_start ft then f ft else Seq.empty
dixon@15814:           in 
dixon@15814:           (case (IsaFTerm.focus_of_fcterm ft) of 
dixon@15814:             (_ $ _) => Seq.append(maux (IsaFTerm.focus_left ft), 
dixon@15929:                        Seq.cons(hereseq, 
dixon@15814:                                   maux (IsaFTerm.focus_right ft)))
dixon@15929:           | (Abs _) => Seq.cons(hereseq, maux (IsaFTerm.focus_abs ft))
dixon@15929:           | leaf => Seq.single (hereseq))
dixon@15814:           end
dixon@15814:     in maux ft end;
dixon@15814: 
dixon@15814: (* search all unifications *)
dixon@16004: fun searchf_tlr_unify_all (sgn, maxidx, ft) lhs = 
paulson@15481:     IsaFTerm.find_fcterm_matches 
dixon@15814:       search_tlr_all_f 
dixon@16004:       (IsaFTerm.clean_unify_ft sgn maxidx lhs)
dixon@16004:       ft;
paulson@15481: 
dixon@15814: (* search only for 'valid' unifiers (non abs subterms and non vars) *)
dixon@16004: fun searchf_tlr_unify_valid (sgn, maxidx, ft) lhs  = 
dixon@15814:     IsaFTerm.find_fcterm_matches 
dixon@15814:       search_tlr_valid_f 
dixon@16004:       (IsaFTerm.clean_unify_ft sgn maxidx lhs)
dixon@16004:       ft;
dixon@15929: 
dixon@15814: 
dixon@15538: (* apply a substitution in the conclusion of the theorem th *)
dixon@15538: (* cfvs are certified free var placeholders for goal params *)
dixon@15538: (* conclthm is a theorem of for just the conclusion *)
dixon@15538: (* m is instantiation/match information *)
dixon@15538: (* rule is the equation for substitution *)
dixon@15538: fun apply_subst_in_concl i th (cfvs, conclthm) rule m = 
dixon@15538:     (RWInst.rw m rule conclthm)
dixon@15855:       |> IsaND.unfix_frees cfvs
dixon@15915:       |> RWInst.beta_eta_contract
dixon@15538:       |> (fn r => Tactic.rtac r i th);
paulson@15481: 
paulson@15481: (* substitute within the conclusion of goal i of gth, using a meta
dixon@15538: equation rule. Note that we assume rule has var indicies zero'd *)
dixon@16004: fun prep_concl_subst i gth = 
paulson@15481:     let 
paulson@15481:       val th = Thm.incr_indexes 1 gth;
paulson@15481:       val tgt_term = Thm.prop_of th;
paulson@15481: 
paulson@15481:       val sgn = Thm.sign_of_thm th;
paulson@15481:       val ctermify = Thm.cterm_of sgn;
paulson@15481:       val trivify = Thm.trivial o ctermify;
paulson@15481: 
paulson@15481:       val (fixedbody, fvs) = IsaND.fix_alls_term i tgt_term;
paulson@15481:       val cfvs = rev (map ctermify fvs);
paulson@15481: 
dixon@15538:       val conclterm = Logic.strip_imp_concl fixedbody;
dixon@15538:       val conclthm = trivify conclterm;
dixon@15538:       val maxidx = Term.maxidx_of_term conclterm;
dixon@16004:       val ft = ((IsaFTerm.focus_right  
dixon@16004:                  o IsaFTerm.focus_left
dixon@16004:                  o IsaFTerm.fcterm_of_term 
dixon@16004:                  o Thm.prop_of) conclthm)
paulson@15481:     in
dixon@16004:       ((cfvs, conclthm), (sgn, maxidx, ft))
paulson@15481:     end;
paulson@15481: 
paulson@15481: (* substitute using an object or meta level equality *)
dixon@15814: fun eqsubst_tac' searchf instepthm i th = 
dixon@15538:     let 
dixon@16004:       val (cvfsconclthm, searchinfo) = prep_concl_subst i th;
dixon@15538:       val stepthms = 
dixon@15538:           Seq.map Drule.zero_var_indexes 
dixon@15538:                   (Seq.of_list (EqRuleData.prep_meta_eq instepthm));
dixon@15538:       fun rewrite_with_thm r =
dixon@15538:           let val (lhs,_) = Logic.dest_equals (Thm.concl_of r);
dixon@16004:           in (searchf searchinfo lhs)
dixon@15538:              :-> (apply_subst_in_concl i th cvfsconclthm r) end;
dixon@16004:     in stepthms :-> rewrite_with_thm end;
dixon@15538: 
dixon@15538: 
dixon@16004: (* Tactic.distinct_subgoals_tac -- fails to free type variables *)
dixon@15959: 
dixon@15959: (* custom version of distinct subgoals that works with term and 
dixon@15959:    type variables. Asssumes th is in beta-eta normal form. 
dixon@15959:    Also, does nothing if flexflex contraints are present. *)
dixon@15959: fun distinct_subgoals th =
dixon@15959:     if List.null (Thm.tpairs_of th) then
dixon@15959:       let val (fixes,fixedthm) = IsaND.fix_vars_and_tvars th
dixon@15959:         val (fixedthconcl,cprems) = IsaND.hide_prems fixedthm
dixon@15959:       in
dixon@15959:         IsaND.unfix_frees_and_tfrees 
dixon@15959:           fixes
dixon@15959:           (Drule.implies_intr_list 
dixon@15959:              (Library.gen_distinct 
dixon@15959:                 (fn (x, y) => Thm.term_of x = Thm.term_of y)
dixon@15959:                 cprems) fixedthconcl)
dixon@15959:       end
dixon@15959:     else th;
dixon@15538: 
dixon@15936: (* General substiuttion of multiple occurances using one of 
dixon@15936:    the given theorems*)
dixon@15959: exception eqsubst_occL_exp of 
dixon@15959:           string * (int list) * (Thm.thm list) * int * Thm.thm;
dixon@16004: fun skip_first_occs_search occ srchf sinfo lhs = 
dixon@16004:     case (IsaPLib.skipto_seqseq occ (srchf sinfo lhs)) of 
dixon@16004:       IsaPLib.skipmore _ => Seq.empty
dixon@16004:     | IsaPLib.skipseq ss => Seq.flat ss;
dixon@16004: 
dixon@16004: fun eqsubst_tac occL thms i th = 
dixon@15936:     let val nprems = Thm.nprems_of th in
dixon@15936:       if nprems < i then Seq.empty else
dixon@15936:       let val thmseq = (Seq.of_list thms) 
dixon@15936:         fun apply_occ occ th = 
dixon@15936:             thmseq :-> 
dixon@16004:                     (fn r => eqsubst_tac' (skip_first_occs_search 
dixon@15936:                                     occ searchf_tlr_unify_valid) r
dixon@15936:                                  (i + ((Thm.nprems_of th) - nprems))
dixon@15936:                                  th);
dixon@16004:         val sortedoccL = 
dixon@16004:             Library.sort (Library.rev_order o Library.int_ord) occL;
dixon@15936:       in
dixon@16004:         Seq.map distinct_subgoals (Seq.EVERY (map apply_occ sortedoccL) th)
dixon@15936:       end
dixon@15959:     end
dixon@15959:     handle THM _ => raise eqsubst_occL_exp ("THM",occL,thms,i,th);
dixon@15959: 
paulson@15481: 
paulson@15481: (* inthms are the given arguments in Isar, and treated as eqstep with
paulson@15481:    the first one, then the second etc *)
dixon@15936: fun eqsubst_meth occL inthms =
paulson@15481:     Method.METHOD 
dixon@15538:       (fn facts =>
dixon@15936:           HEADGOAL ( Method.insert_tac facts THEN' eqsubst_tac occL inthms ));
paulson@15481: 
dixon@16004: (* apply a substitution inside assumption j, keeps asm in the same place *)
dixon@16007: fun apply_subst_in_asm i th rule ((cfvs, j, ngoalprems, pth),m) = 
dixon@16004:     let 
dixon@16004:       val th2 = Thm.rotate_rule (j - 1) i th; (* put premice first *)
dixon@16004:       val preelimrule = 
dixon@16004:           (RWInst.rw m rule pth)
dixon@16004:             |> (Seq.hd o Tactic.prune_params_tac)
dixon@16004:             |> Thm.permute_prems 0 ~1 (* put old asm first *)
dixon@16004:             |> IsaND.unfix_frees cfvs (* unfix any global params *)
dixon@16004:             |> RWInst.beta_eta_contract; (* normal form *)
dixon@16007:   (*    val elimrule = 
dixon@16004:           preelimrule
dixon@16004:             |> Tactic.make_elim (* make into elim rule *)
dixon@16004:             |> Thm.lift_rule (th2, i); (* lift into context *)
dixon@16007:    *)
dixon@16004:     in
dixon@16004:       (* ~j because new asm starts at back, thus we subtract 1 *)
dixon@16007:       Seq.map (Thm.rotate_rule (~j) ((Thm.nprems_of rule) + i))
dixon@16007:       (Tactic.dtac preelimrule i th2)
dixon@16007: 
dixon@16007:       (* (Thm.bicompose 
dixon@16004:                  false (* use unification *)
dixon@16004:                  (true, (* elim resolution *)
dixon@16007:                   elimrule, (2 + (Thm.nprems_of rule)) - ngoalprems)
dixon@16007:                  i th2) *)
dixon@16004:     end;
paulson@15481: 
paulson@15481: 
dixon@15538: (* prepare to substitute within the j'th premise of subgoal i of gth,
dixon@15538: using a meta-level equation. Note that we assume rule has var indicies
dixon@15538: zero'd. Note that we also assume that premt is the j'th premice of
dixon@15538: subgoal i of gth. Note the repetition of work done for each
dixon@15538: assumption, i.e. this can be made more efficient for search over
dixon@15538: multiple assumptions.  *)
dixon@16004: fun prep_subst_in_asm i gth j = 
paulson@15481:     let 
paulson@15481:       val th = Thm.incr_indexes 1 gth;
paulson@15481:       val tgt_term = Thm.prop_of th;
paulson@15481: 
paulson@15481:       val sgn = Thm.sign_of_thm th;
paulson@15481:       val ctermify = Thm.cterm_of sgn;
paulson@15481:       val trivify = Thm.trivial o ctermify;
paulson@15481: 
paulson@15481:       val (fixedbody, fvs) = IsaND.fix_alls_term i tgt_term;
paulson@15481:       val cfvs = rev (map ctermify fvs);
paulson@15481: 
dixon@15538:       val asmt = Library.nth_elem(j - 1,(Logic.strip_imp_prems fixedbody));
dixon@15538:       val asm_nprems = length (Logic.strip_imp_prems asmt);
dixon@15538: 
dixon@15538:       val pth = trivify asmt;
dixon@15538:       val maxidx = Term.maxidx_of_term asmt;
dixon@15538: 
dixon@16004:       val ft = ((IsaFTerm.focus_right 
dixon@16004:                  o IsaFTerm.fcterm_of_term 
dixon@16004:                  o Thm.prop_of) pth)
dixon@16004:     in ((cfvs, j, asm_nprems, pth), (sgn, maxidx, ft)) end;
paulson@15481: 
dixon@15538: (* prepare subst in every possible assumption *)
dixon@16004: fun prep_subst_in_asms i gth = 
dixon@16004:     map (prep_subst_in_asm i gth)
dixon@16004:         ((rev o IsaPLib.mk_num_list o length) 
dixon@16004:            (Logic.prems_of_goal (Thm.prop_of gth) i));
dixon@15538: 
dixon@15538: 
dixon@15538: (* substitute in an assumption using an object or meta level equality *)
dixon@16004: fun eqsubst_asm_tac' searchf skipocc instepthm i th = 
dixon@15538:     let 
dixon@16004:       val asmpreps = prep_subst_in_asms i th;
dixon@15538:       val stepthms = 
dixon@15538:           Seq.map Drule.zero_var_indexes 
dixon@16004:               (Seq.of_list (EqRuleData.prep_meta_eq instepthm))
dixon@16004:       fun rewrite_with_thm r =
dixon@16004:           let val (lhs,_) = Logic.dest_equals (Thm.concl_of r)
dixon@16004:             fun occ_search occ [] = Seq.empty
dixon@16004:               | occ_search occ ((asminfo, searchinfo)::moreasms) =
dixon@16004:                 (case searchf searchinfo occ lhs of 
dixon@16004:                    IsaPLib.skipmore i => occ_search i moreasms
dixon@16004:                  | IsaPLib.skipseq ss => 
dixon@16004:                    Seq.append (Seq.map (Library.pair asminfo)
dixon@16004:                                        (Seq.flat ss), 
dixon@16004:                                occ_search 1 moreasms))
dixon@16004:                               (* find later substs also *)
dixon@16004:           in 
dixon@16004:             (occ_search skipocc asmpreps) :-> (apply_subst_in_asm i th r)
dixon@16004:           end;
dixon@16004:     in stepthms :-> rewrite_with_thm end;
dixon@15538: 
dixon@16004: 
dixon@16004: fun skip_first_asm_occs_search searchf sinfo occ lhs = 
dixon@16004:     IsaPLib.skipto_seqseq occ (searchf sinfo lhs);
dixon@16004: 
dixon@16004: fun eqsubst_asm_tac occL thms i th = 
dixon@16004:     let val nprems = Thm.nprems_of th 
dixon@15538:     in
dixon@16004:       if nprems < i then Seq.empty else
dixon@16004:       let val thmseq = (Seq.of_list thms) 
dixon@16004:         fun apply_occ occK th = 
dixon@16004:             thmseq :-> 
dixon@16004:                     (fn r => 
dixon@16004:                         eqsubst_asm_tac' (skip_first_asm_occs_search 
dixon@16004:                                             searchf_tlr_unify_valid) occK r
dixon@16004:                                          (i + ((Thm.nprems_of th) - nprems))
dixon@16004:                                          th);
dixon@16004:         val sortedoccs = 
dixon@16004:             Library.sort (Library.rev_order o Library.int_ord) occL
dixon@16004:       in
dixon@16004:         Seq.map distinct_subgoals
dixon@16004:                 (Seq.EVERY (map apply_occ sortedoccs) th)
dixon@16004:       end
dixon@16004:     end
dixon@16004:     handle THM _ => raise eqsubst_occL_exp ("THM",occL,thms,i,th);
paulson@15481: 
paulson@15481: (* inthms are the given arguments in Isar, and treated as eqstep with
paulson@15481:    the first one, then the second etc *)
dixon@15936: fun eqsubst_asm_meth occL inthms =
paulson@15481:     Method.METHOD 
dixon@15538:       (fn facts =>
dixon@15936:           HEADGOAL (Method.insert_tac facts THEN' eqsubst_asm_tac occL inthms ));
paulson@15481: 
paulson@15481: (* combination method that takes a flag (true indicates that subst
paulson@15481: should be done to an assumption, false = apply to the conclusion of
paulson@15481: the goal) as well as the theorems to use *)
dixon@15936: fun meth ((asmflag, occL), inthms) ctxt = 
dixon@15936:     if asmflag then eqsubst_asm_meth occL inthms else eqsubst_meth occL inthms;
paulson@15481: 
paulson@15481: (* syntax for options, given "(asm)" will give back true, without
paulson@15481:    gives back false *)
paulson@15481: val options_syntax =
paulson@15481:     (Args.parens (Args.$$$ "asm") >> (K true)) ||
paulson@15481:      (Scan.succeed false);
dixon@15936: 
dixon@15929: val ith_syntax =
dixon@15936:     (Args.parens (Scan.repeat Args.nat))
dixon@15936:       || (Scan.succeed [0]);
paulson@15481: 
paulson@15481: (* method syntax, first take options, then theorems *)
paulson@15481: fun meth_syntax meth src ctxt =
paulson@15481:     meth (snd (Method.syntax ((Scan.lift options_syntax) 
dixon@15929:                                 -- (Scan.lift ith_syntax) 
paulson@15481:                                 -- Attrib.local_thms) src ctxt)) 
paulson@15481:          ctxt;
paulson@15481: 
paulson@15481: (* setup function for adding method to theory. *)
paulson@15481: val setup = 
paulson@15481:     [Method.add_method ("subst", meth_syntax meth, "Substiution with an equation. Use \"(asm)\" option to substitute in an assumption.")];
paulson@15481: 
paulson@15481: end;