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(* -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- *)
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(* Title: Provers/eqsubst.ML
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Author: Lucas Dixon, University of Edinburgh
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lucas.dixon@ed.ac.uk
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Modified: 18 Feb 2005 - Lucas -
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Created: 29 Jan 2005
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*)
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(* -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- *)
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(* DESCRIPTION:
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A Tactic to perform a substiution using an equation.
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*)
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(* -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- *)
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(* Logic specific data stub *)
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signature EQRULE_DATA =
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sig
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(* to make a meta equality theorem in the current logic *)
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val prep_meta_eq : thm -> thm list
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end;
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(* the signature of an instance of the SQSUBST tactic *)
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signature EQSUBST_TAC =
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sig
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exception eqsubst_occL_exp of
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string * (int list) * (Thm.thm list) * int * Thm.thm;
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type match =
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((Term.indexname * (Term.sort * Term.typ)) list (* type instantiations *)
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* (Term.indexname * (Term.typ * Term.term)) list) (* term instantiations *)
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* (string * Term.typ) list (* fake named type abs env *)
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* (string * Term.typ) list (* type abs env *)
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* Term.term (* outer term *)
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type searchinfo =
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Sign.sg (* sign for matching *)
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* int (* maxidx *)
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* BasicIsaFTerm.FcTerm (* focusterm to search under *)
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val prep_subst_in_asm :
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int (* subgoal to subst in *)
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-> Thm.thm (* target theorem with subgoals *)
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-> int (* premise to subst in *)
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-> (Thm.cterm list (* certified free var placeholders for vars *)
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* int (* premice no. to subst *)
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* int (* number of assumptions of premice *)
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* Thm.thm) (* premice as a new theorem for forward reasoning *)
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* searchinfo (* search info: prem id etc *)
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val prep_subst_in_asms :
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int (* subgoal to subst in *)
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-> Thm.thm (* target theorem with subgoals *)
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-> ((Thm.cterm list (* certified free var placeholders for vars *)
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* int (* premice no. to subst *)
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* int (* number of assumptions of premice *)
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* Thm.thm) (* premice as a new theorem for forward reasoning *)
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* searchinfo) list
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val apply_subst_in_asm :
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int (* subgoal *)
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-> Thm.thm (* overall theorem *)
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-> Thm.thm (* rule *)
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-> (Thm.cterm list (* certified free var placeholders for vars *)
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* int (* assump no being subst *)
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* int (* num of premises of asm *)
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* Thm.thm) (* premthm *)
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* match
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-> Thm.thm Seq.seq
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val prep_concl_subst :
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int (* subgoal *)
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-> Thm.thm (* overall goal theorem *)
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-> (Thm.cterm list * Thm.thm) * searchinfo (* (cvfs, conclthm), matchf *)
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val apply_subst_in_concl :
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int (* subgoal *)
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-> Thm.thm (* thm with all goals *)
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-> Thm.cterm list (* certified free var placeholders for vars *)
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* Thm.thm (* trivial thm of goal concl *)
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(* possible matches/unifiers *)
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-> Thm.thm (* rule *)
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-> match
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-> Thm.thm Seq.seq (* substituted goal *)
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(* basic notion of search *)
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val searchf_tlr_unify_all :
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(searchinfo
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-> Term.term (* lhs *)
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-> match Seq.seq Seq.seq)
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val searchf_tlr_unify_valid :
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(searchinfo
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-> Term.term (* lhs *)
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-> match Seq.seq Seq.seq)
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(* specialise search constructor for conclusion skipping occurnaces. *)
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val skip_first_occs_search :
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int -> ('a -> 'b -> 'c Seq.seq Seq.seq) -> 'a -> 'b -> 'c Seq.seq
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(* specialised search constructor for assumptions using skips *)
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val skip_first_asm_occs_search :
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('a -> 'b -> 'c Seq.seq Seq.seq) ->
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'a -> int -> 'b -> 'c IsaPLib.skipseqT
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(* tactics and methods *)
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val eqsubst_asm_meth : int list -> Thm.thm list -> Proof.method
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val eqsubst_asm_tac :
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int list -> Thm.thm list -> int -> Thm.thm -> Thm.thm Seq.seq
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val eqsubst_asm_tac' :
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(* search function with skips *)
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(searchinfo -> int -> Term.term -> match IsaPLib.skipseqT)
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-> int (* skip to *)
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-> Thm.thm (* rule *)
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-> int (* subgoal number *)
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-> Thm.thm (* tgt theorem with subgoals *)
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-> Thm.thm Seq.seq (* new theorems *)
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val eqsubst_meth : int list -> Thm.thm list -> Proof.method
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val eqsubst_tac :
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int list -> Thm.thm list -> int -> Thm.thm -> Thm.thm Seq.seq
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val eqsubst_tac' :
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(searchinfo -> Term.term -> match Seq.seq)
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-> Thm.thm -> int -> Thm.thm -> Thm.thm Seq.seq
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val meth : (bool * int list) * Thm.thm list -> Proof.context -> Proof.method
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val setup : (Theory.theory -> Theory.theory) list
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end;
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functor EQSubstTacFUN (structure EqRuleData : EQRULE_DATA)
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: EQSUBST_TAC
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= struct
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(* a type abriviation for match information *)
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type match =
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((Term.indexname * (Term.sort * Term.typ)) list (* type instantiations *)
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* (Term.indexname * (Term.typ * Term.term)) list) (* term instantiations *)
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* (string * Term.typ) list (* fake named type abs env *)
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* (string * Term.typ) list (* type abs env *)
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* Term.term (* outer term *)
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type searchinfo =
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Sign.sg (* sign for matching *)
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* int (* maxidx *)
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* BasicIsaFTerm.FcTerm (* focusterm to search under *)
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(* FOR DEBUGGING...
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type trace_subst_errT = int (* subgoal *)
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* Thm.thm (* thm with all goals *)
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* (Thm.cterm list (* certified free var placeholders for vars *)
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* Thm.thm) (* trivial thm of goal concl *)
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(* possible matches/unifiers *)
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* Thm.thm (* rule *)
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* (((Term.indexname * Term.typ) list (* type instantiations *)
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* (Term.indexname * Term.term) list ) (* term instantiations *)
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* (string * Term.typ) list (* Type abs env *)
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* Term.term) (* outer term *);
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val trace_subst_err = (ref NONE : trace_subst_errT option ref);
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val trace_subst_search = ref false;
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exception trace_subst_exp of trace_subst_errT;
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*)
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(* also defined in /HOL/Tools/inductive_codegen.ML,
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maybe move this to seq.ML ? *)
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infix 5 :->;
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fun s :-> f = Seq.flat (Seq.map f s);
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(* search from top, left to right, then down *)
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fun search_tlr_all_f f ft =
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let
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fun maux ft =
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let val t' = (IsaFTerm.focus_of_fcterm ft)
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(* val _ =
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if !trace_subst_search then
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(writeln ("Examining: " ^ (TermLib.string_of_term t'));
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TermLib.writeterm t'; ())
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else (); *)
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in
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(case t' of
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(_ $ _) => Seq.append(maux (IsaFTerm.focus_left ft),
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Seq.cons(f ft,
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maux (IsaFTerm.focus_right ft)))
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| (Abs _) => Seq.cons(f ft, maux (IsaFTerm.focus_abs ft))
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| leaf => Seq.single (f ft)) end
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in maux ft end;
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(* search from top, left to right, then down *)
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fun search_tlr_valid_f f ft =
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let
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fun maux ft =
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let
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val hereseq = if IsaFTerm.valid_match_start ft then f ft else Seq.empty
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in
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(case (IsaFTerm.focus_of_fcterm ft) of
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(_ $ _) => Seq.append(maux (IsaFTerm.focus_left ft),
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Seq.cons(hereseq,
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maux (IsaFTerm.focus_right ft)))
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| (Abs _) => Seq.cons(hereseq, maux (IsaFTerm.focus_abs ft))
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| leaf => Seq.single (hereseq))
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end
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in maux ft end;
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(* search all unifications *)
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fun searchf_tlr_unify_all (sgn, maxidx, ft) lhs =
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IsaFTerm.find_fcterm_matches
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search_tlr_all_f
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(IsaFTerm.clean_unify_ft sgn maxidx lhs)
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ft;
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(* search only for 'valid' unifiers (non abs subterms and non vars) *)
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fun searchf_tlr_unify_valid (sgn, maxidx, ft) lhs =
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IsaFTerm.find_fcterm_matches
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search_tlr_valid_f
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(IsaFTerm.clean_unify_ft sgn maxidx lhs)
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ft;
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(* apply a substitution in the conclusion of the theorem th *)
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(* cfvs are certified free var placeholders for goal params *)
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(* conclthm is a theorem of for just the conclusion *)
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(* m is instantiation/match information *)
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(* rule is the equation for substitution *)
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fun apply_subst_in_concl i th (cfvs, conclthm) rule m =
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(RWInst.rw m rule conclthm)
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|> IsaND.unfix_frees cfvs
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|> RWInst.beta_eta_contract
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|> (fn r => Tactic.rtac r i th);
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(*
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|> (fn r => Thm.bicompose false (false, r, Thm.nprems_of r) i th)
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*)
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(* substitute within the conclusion of goal i of gth, using a meta
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equation rule. Note that we assume rule has var indicies zero'd *)
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fun prep_concl_subst i gth =
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let
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val th = Thm.incr_indexes 1 gth;
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val tgt_term = Thm.prop_of th;
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val sgn = Thm.sign_of_thm th;
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val ctermify = Thm.cterm_of sgn;
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val trivify = Thm.trivial o ctermify;
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val (fixedbody, fvs) = IsaND.fix_alls_term i tgt_term;
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val cfvs = rev (map ctermify fvs);
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val conclterm = Logic.strip_imp_concl fixedbody;
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val conclthm = trivify conclterm;
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val maxidx = Term.maxidx_of_term conclterm;
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val ft = ((IsaFTerm.focus_right
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o IsaFTerm.focus_left
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o IsaFTerm.fcterm_of_term
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o Thm.prop_of) conclthm)
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in
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((cfvs, conclthm), (sgn, maxidx, ft))
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end;
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paulson@15481
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(* substitute using an object or meta level equality *)
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fun eqsubst_tac' searchf instepthm i th =
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let
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val (cvfsconclthm, searchinfo) = prep_concl_subst i th;
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val stepthms =
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Seq.map Drule.zero_var_indexes
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(Seq.of_list (EqRuleData.prep_meta_eq instepthm));
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fun rewrite_with_thm r =
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let val (lhs,_) = Logic.dest_equals (Thm.concl_of r);
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in (searchf searchinfo lhs)
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:-> (apply_subst_in_concl i th cvfsconclthm r) end;
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in stepthms :-> rewrite_with_thm end;
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(* Tactic.distinct_subgoals_tac -- fails to free type variables *)
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(* custom version of distinct subgoals that works with term and
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type variables. Asssumes th is in beta-eta normal form.
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Also, does nothing if flexflex contraints are present. *)
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fun distinct_subgoals th =
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if List.null (Thm.tpairs_of th) then
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let val (fixes,fixedthm) = IsaND.fix_vars_and_tvars th
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dixon@15959
|
286 |
val (fixedthconcl,cprems) = IsaND.hide_prems fixedthm
|
dixon@15959
|
287 |
in
|
dixon@15959
|
288 |
IsaND.unfix_frees_and_tfrees
|
dixon@15959
|
289 |
fixes
|
dixon@15959
|
290 |
(Drule.implies_intr_list
|
dixon@15959
|
291 |
(Library.gen_distinct
|
dixon@15959
|
292 |
(fn (x, y) => Thm.term_of x = Thm.term_of y)
|
dixon@15959
|
293 |
cprems) fixedthconcl)
|
dixon@15959
|
294 |
end
|
dixon@15959
|
295 |
else th;
|
dixon@15538
|
296 |
|
dixon@15936
|
297 |
(* General substiuttion of multiple occurances using one of
|
dixon@15936
|
298 |
the given theorems*)
|
dixon@15959
|
299 |
exception eqsubst_occL_exp of
|
dixon@15959
|
300 |
string * (int list) * (Thm.thm list) * int * Thm.thm;
|
dixon@16004
|
301 |
fun skip_first_occs_search occ srchf sinfo lhs =
|
dixon@16004
|
302 |
case (IsaPLib.skipto_seqseq occ (srchf sinfo lhs)) of
|
dixon@16004
|
303 |
IsaPLib.skipmore _ => Seq.empty
|
dixon@16004
|
304 |
| IsaPLib.skipseq ss => Seq.flat ss;
|
dixon@16004
|
305 |
|
dixon@16004
|
306 |
fun eqsubst_tac occL thms i th =
|
dixon@15936
|
307 |
let val nprems = Thm.nprems_of th in
|
dixon@15936
|
308 |
if nprems < i then Seq.empty else
|
dixon@15936
|
309 |
let val thmseq = (Seq.of_list thms)
|
dixon@15936
|
310 |
fun apply_occ occ th =
|
dixon@15936
|
311 |
thmseq :->
|
dixon@16004
|
312 |
(fn r => eqsubst_tac' (skip_first_occs_search
|
dixon@15936
|
313 |
occ searchf_tlr_unify_valid) r
|
dixon@15936
|
314 |
(i + ((Thm.nprems_of th) - nprems))
|
dixon@15936
|
315 |
th);
|
dixon@16004
|
316 |
val sortedoccL =
|
dixon@16004
|
317 |
Library.sort (Library.rev_order o Library.int_ord) occL;
|
dixon@15936
|
318 |
in
|
dixon@16004
|
319 |
Seq.map distinct_subgoals (Seq.EVERY (map apply_occ sortedoccL) th)
|
dixon@15936
|
320 |
end
|
dixon@15959
|
321 |
end
|
dixon@15959
|
322 |
handle THM _ => raise eqsubst_occL_exp ("THM",occL,thms,i,th);
|
dixon@15959
|
323 |
|
paulson@15481
|
324 |
|
paulson@15481
|
325 |
(* inthms are the given arguments in Isar, and treated as eqstep with
|
paulson@15481
|
326 |
the first one, then the second etc *)
|
dixon@15936
|
327 |
fun eqsubst_meth occL inthms =
|
paulson@15481
|
328 |
Method.METHOD
|
dixon@15538
|
329 |
(fn facts =>
|
dixon@15936
|
330 |
HEADGOAL ( Method.insert_tac facts THEN' eqsubst_tac occL inthms ));
|
paulson@15481
|
331 |
|
dixon@16004
|
332 |
(* apply a substitution inside assumption j, keeps asm in the same place *)
|
dixon@16004
|
333 |
fun apply_subst_in_asm i th rule ((cfvs, j, nprems, pth),m) =
|
dixon@16004
|
334 |
let
|
dixon@16004
|
335 |
val th2 = Thm.rotate_rule (j - 1) i th; (* put premice first *)
|
dixon@16004
|
336 |
val preelimrule =
|
dixon@16004
|
337 |
(RWInst.rw m rule pth)
|
dixon@16004
|
338 |
|> (Seq.hd o Tactic.prune_params_tac)
|
dixon@16004
|
339 |
|> Thm.permute_prems 0 ~1 (* put old asm first *)
|
dixon@16004
|
340 |
|> IsaND.unfix_frees cfvs (* unfix any global params *)
|
dixon@16004
|
341 |
|> RWInst.beta_eta_contract; (* normal form *)
|
dixon@16004
|
342 |
val elimrule =
|
dixon@16004
|
343 |
preelimrule
|
dixon@16004
|
344 |
|> Tactic.make_elim (* make into elim rule *)
|
dixon@16004
|
345 |
|> Thm.lift_rule (th2, i); (* lift into context *)
|
dixon@16004
|
346 |
in
|
dixon@16004
|
347 |
(* ~j because new asm starts at back, thus we subtract 1 *)
|
dixon@16004
|
348 |
Seq.map (Thm.rotate_rule (~j) (nprems + i))
|
dixon@16004
|
349 |
(Thm.bicompose
|
dixon@16004
|
350 |
false (* use unification *)
|
dixon@16004
|
351 |
(true, (* elim resolution *)
|
dixon@16004
|
352 |
elimrule, 2 + nprems)
|
dixon@16004
|
353 |
i th2)
|
dixon@16004
|
354 |
end;
|
dixon@15538
|
355 |
|
dixon@15538
|
356 |
|
dixon@15538
|
357 |
(* prepare to substitute within the j'th premise of subgoal i of gth,
|
dixon@15538
|
358 |
using a meta-level equation. Note that we assume rule has var indicies
|
dixon@15538
|
359 |
zero'd. Note that we also assume that premt is the j'th premice of
|
dixon@15538
|
360 |
subgoal i of gth. Note the repetition of work done for each
|
dixon@15538
|
361 |
assumption, i.e. this can be made more efficient for search over
|
dixon@15538
|
362 |
multiple assumptions. *)
|
dixon@16004
|
363 |
fun prep_subst_in_asm i gth j =
|
paulson@15481
|
364 |
let
|
paulson@15481
|
365 |
val th = Thm.incr_indexes 1 gth;
|
paulson@15481
|
366 |
val tgt_term = Thm.prop_of th;
|
paulson@15481
|
367 |
|
paulson@15481
|
368 |
val sgn = Thm.sign_of_thm th;
|
paulson@15481
|
369 |
val ctermify = Thm.cterm_of sgn;
|
paulson@15481
|
370 |
val trivify = Thm.trivial o ctermify;
|
paulson@15481
|
371 |
|
paulson@15481
|
372 |
val (fixedbody, fvs) = IsaND.fix_alls_term i tgt_term;
|
paulson@15481
|
373 |
val cfvs = rev (map ctermify fvs);
|
paulson@15481
|
374 |
|
dixon@15538
|
375 |
val asmt = Library.nth_elem(j - 1,(Logic.strip_imp_prems fixedbody));
|
dixon@15538
|
376 |
val asm_nprems = length (Logic.strip_imp_prems asmt);
|
dixon@15538
|
377 |
|
dixon@15538
|
378 |
val pth = trivify asmt;
|
dixon@15538
|
379 |
val maxidx = Term.maxidx_of_term asmt;
|
dixon@15538
|
380 |
|
dixon@16004
|
381 |
val ft = ((IsaFTerm.focus_right
|
dixon@16004
|
382 |
o IsaFTerm.fcterm_of_term
|
dixon@16004
|
383 |
o Thm.prop_of) pth)
|
dixon@16004
|
384 |
in ((cfvs, j, asm_nprems, pth), (sgn, maxidx, ft)) end;
|
paulson@15481
|
385 |
|
dixon@15538
|
386 |
(* prepare subst in every possible assumption *)
|
dixon@16004
|
387 |
fun prep_subst_in_asms i gth =
|
dixon@16004
|
388 |
map (prep_subst_in_asm i gth)
|
dixon@16004
|
389 |
((rev o IsaPLib.mk_num_list o length)
|
dixon@16004
|
390 |
(Logic.prems_of_goal (Thm.prop_of gth) i));
|
dixon@15538
|
391 |
|
dixon@15538
|
392 |
|
dixon@15538
|
393 |
(* substitute in an assumption using an object or meta level equality *)
|
dixon@16004
|
394 |
fun eqsubst_asm_tac' searchf skipocc instepthm i th =
|
dixon@15538
|
395 |
let
|
dixon@16004
|
396 |
val asmpreps = prep_subst_in_asms i th;
|
dixon@15538
|
397 |
val stepthms =
|
dixon@15538
|
398 |
Seq.map Drule.zero_var_indexes
|
dixon@16004
|
399 |
(Seq.of_list (EqRuleData.prep_meta_eq instepthm))
|
dixon@16004
|
400 |
fun rewrite_with_thm r =
|
dixon@16004
|
401 |
let val (lhs,_) = Logic.dest_equals (Thm.concl_of r)
|
dixon@16004
|
402 |
fun occ_search occ [] = Seq.empty
|
dixon@16004
|
403 |
| occ_search occ ((asminfo, searchinfo)::moreasms) =
|
dixon@16004
|
404 |
(case searchf searchinfo occ lhs of
|
dixon@16004
|
405 |
IsaPLib.skipmore i => occ_search i moreasms
|
dixon@16004
|
406 |
| IsaPLib.skipseq ss =>
|
dixon@16004
|
407 |
Seq.append (Seq.map (Library.pair asminfo)
|
dixon@16004
|
408 |
(Seq.flat ss),
|
dixon@16004
|
409 |
occ_search 1 moreasms))
|
dixon@16004
|
410 |
(* find later substs also *)
|
dixon@16004
|
411 |
in
|
dixon@16004
|
412 |
(occ_search skipocc asmpreps) :-> (apply_subst_in_asm i th r)
|
dixon@16004
|
413 |
end;
|
dixon@16004
|
414 |
in stepthms :-> rewrite_with_thm end;
|
dixon@15538
|
415 |
|
dixon@16004
|
416 |
|
dixon@16004
|
417 |
fun skip_first_asm_occs_search searchf sinfo occ lhs =
|
dixon@16004
|
418 |
IsaPLib.skipto_seqseq occ (searchf sinfo lhs);
|
dixon@16004
|
419 |
|
dixon@16004
|
420 |
fun eqsubst_asm_tac occL thms i th =
|
dixon@16004
|
421 |
let val nprems = Thm.nprems_of th
|
dixon@15538
|
422 |
in
|
dixon@16004
|
423 |
if nprems < i then Seq.empty else
|
dixon@16004
|
424 |
let val thmseq = (Seq.of_list thms)
|
dixon@16004
|
425 |
fun apply_occ occK th =
|
dixon@16004
|
426 |
thmseq :->
|
dixon@16004
|
427 |
(fn r =>
|
dixon@16004
|
428 |
eqsubst_asm_tac' (skip_first_asm_occs_search
|
dixon@16004
|
429 |
searchf_tlr_unify_valid) occK r
|
dixon@16004
|
430 |
(i + ((Thm.nprems_of th) - nprems))
|
dixon@16004
|
431 |
th);
|
dixon@16004
|
432 |
val sortedoccs =
|
dixon@16004
|
433 |
Library.sort (Library.rev_order o Library.int_ord) occL
|
dixon@16004
|
434 |
in
|
dixon@16004
|
435 |
Seq.map distinct_subgoals
|
dixon@16004
|
436 |
(Seq.EVERY (map apply_occ sortedoccs) th)
|
dixon@16004
|
437 |
end
|
dixon@16004
|
438 |
end
|
dixon@16004
|
439 |
handle THM _ => raise eqsubst_occL_exp ("THM",occL,thms,i,th);
|
paulson@15481
|
440 |
|
paulson@15481
|
441 |
(* inthms are the given arguments in Isar, and treated as eqstep with
|
paulson@15481
|
442 |
the first one, then the second etc *)
|
dixon@15936
|
443 |
fun eqsubst_asm_meth occL inthms =
|
paulson@15481
|
444 |
Method.METHOD
|
dixon@15538
|
445 |
(fn facts =>
|
dixon@15936
|
446 |
HEADGOAL (Method.insert_tac facts THEN' eqsubst_asm_tac occL inthms ));
|
paulson@15481
|
447 |
|
paulson@15481
|
448 |
(* combination method that takes a flag (true indicates that subst
|
paulson@15481
|
449 |
should be done to an assumption, false = apply to the conclusion of
|
paulson@15481
|
450 |
the goal) as well as the theorems to use *)
|
dixon@15936
|
451 |
fun meth ((asmflag, occL), inthms) ctxt =
|
dixon@15936
|
452 |
if asmflag then eqsubst_asm_meth occL inthms else eqsubst_meth occL inthms;
|
paulson@15481
|
453 |
|
paulson@15481
|
454 |
(* syntax for options, given "(asm)" will give back true, without
|
paulson@15481
|
455 |
gives back false *)
|
paulson@15481
|
456 |
val options_syntax =
|
paulson@15481
|
457 |
(Args.parens (Args.$$$ "asm") >> (K true)) ||
|
paulson@15481
|
458 |
(Scan.succeed false);
|
dixon@15936
|
459 |
|
dixon@15929
|
460 |
val ith_syntax =
|
dixon@15936
|
461 |
(Args.parens (Scan.repeat Args.nat))
|
dixon@15936
|
462 |
|| (Scan.succeed [0]);
|
paulson@15481
|
463 |
|
paulson@15481
|
464 |
(* method syntax, first take options, then theorems *)
|
paulson@15481
|
465 |
fun meth_syntax meth src ctxt =
|
paulson@15481
|
466 |
meth (snd (Method.syntax ((Scan.lift options_syntax)
|
dixon@15929
|
467 |
-- (Scan.lift ith_syntax)
|
paulson@15481
|
468 |
-- Attrib.local_thms) src ctxt))
|
paulson@15481
|
469 |
ctxt;
|
paulson@15481
|
470 |
|
paulson@15481
|
471 |
(* setup function for adding method to theory. *)
|
paulson@15481
|
472 |
val setup =
|
paulson@15481
|
473 |
[Method.add_method ("subst", meth_syntax meth, "Substiution with an equation. Use \"(asm)\" option to substitute in an assumption.")];
|
paulson@15481
|
474 |
|
paulson@15481
|
475 |
end; |