src/Pure/tactic.ML
author paulson
Wed Aug 18 10:54:44 1999 +0200 (1999-08-18)
changeset 7248 322151fe6f02
parent 6979 4b9963810121
child 7491 95a4af0e10a7
permissions -rw-r--r--
new primitive rule permute_prems to underlie defer_tac and rotate_prems
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(*  Title: 	Pure/tactic.ML
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    ID:         $Id$
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    Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory
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    Copyright   1991  University of Cambridge
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Tactics 
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*)
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signature TACTIC =
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  sig
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  val ares_tac		: thm list -> int -> tactic
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  val asm_rewrite_goal_tac:
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    bool*bool*bool -> (meta_simpset -> tactic) -> meta_simpset -> int -> tactic
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  val assume_tac	: int -> tactic
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  val atac	: int ->tactic
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  val bimatch_from_nets_tac: 
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      (int*(bool*thm)) Net.net * (int*(bool*thm)) Net.net -> int -> tactic
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  val bimatch_tac	: (bool*thm)list -> int -> tactic
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  val biresolution_from_nets_tac: 
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	('a list -> (bool * thm) list) ->
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	bool -> 'a Net.net * 'a Net.net -> int -> tactic
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  val biresolve_from_nets_tac: 
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      (int*(bool*thm)) Net.net * (int*(bool*thm)) Net.net -> int -> tactic
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  val biresolve_tac	: (bool*thm)list -> int -> tactic
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  val build_net	: thm list -> (int*thm) Net.net
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  val build_netpair:    (int*(bool*thm)) Net.net * (int*(bool*thm)) Net.net ->
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      (bool*thm)list -> (int*(bool*thm)) Net.net * (int*(bool*thm)) Net.net
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  val compose_inst_tac	: (string*string)list -> (bool*thm*int) -> 
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                          int -> tactic
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  val compose_tac	: (bool * thm * int) -> int -> tactic 
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  val cut_facts_tac	: thm list -> int -> tactic
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  val cut_inst_tac	: (string*string)list -> thm -> int -> tactic   
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  val defer_tac 	: int -> tactic
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  val distinct_subgoals_tac	: tactic
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  val dmatch_tac	: thm list -> int -> tactic
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  val dresolve_tac	: thm list -> int -> tactic
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  val dres_inst_tac	: (string*string)list -> thm -> int -> tactic   
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  val dtac		: thm -> int ->tactic
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  val etac		: thm -> int ->tactic
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  val eq_assume_tac	: int -> tactic   
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  val ematch_tac	: thm list -> int -> tactic
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  val eresolve_tac	: thm list -> int -> tactic
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  val eres_inst_tac	: (string*string)list -> thm -> int -> tactic
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  val filter_prems_tac  : (term -> bool) -> int -> tactic  
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  val filter_thms	: (term*term->bool) -> int*term*thm list -> thm list
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  val filt_resolve_tac	: thm list -> int -> int -> tactic
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  val flexflex_tac	: tactic
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  val fold_goals_tac	: thm list -> tactic
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  val fold_tac		: thm list -> tactic
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  val forward_tac	: thm list -> int -> tactic   
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  val forw_inst_tac	: (string*string)list -> thm -> int -> tactic
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  val insert_tagged_brl : ('a*(bool*thm)) * 
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                          (('a*(bool*thm))Net.net * ('a*(bool*thm))Net.net) ->
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                          ('a*(bool*thm))Net.net * ('a*(bool*thm))Net.net
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  val delete_tagged_brl	: (bool*thm) * 
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                         ((int*(bool*thm))Net.net * (int*(bool*thm))Net.net) ->
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                    (int*(bool*thm))Net.net * (int*(bool*thm))Net.net
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  val is_fact		: thm -> bool
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  val lessb		: (bool * thm) * (bool * thm) -> bool
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  val lift_inst_rule	: thm * int * (string*string)list * thm -> thm
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  val make_elim		: thm -> thm
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  val match_from_net_tac	: (int*thm) Net.net -> int -> tactic
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  val match_tac	: thm list -> int -> tactic
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  val metacut_tac	: thm -> int -> tactic
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  val net_bimatch_tac	: (bool*thm) list -> int -> tactic
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  val net_biresolve_tac	: (bool*thm) list -> int -> tactic
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  val net_match_tac	: thm list -> int -> tactic
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  val net_resolve_tac	: thm list -> int -> tactic
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  val orderlist		: (int * 'a) list -> 'a list
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  val PRIMITIVE		: (thm -> thm) -> tactic  
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  val PRIMSEQ		: (thm -> thm Seq.seq) -> tactic  
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  val prune_params_tac	: tactic
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  val rename_tac	: string -> int -> tactic
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  val rename_last_tac	: string -> string list -> int -> tactic
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  val resolve_from_net_tac	: (int*thm) Net.net -> int -> tactic
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  val resolve_tac	: thm list -> int -> tactic
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  val res_inst_tac	: (string*string)list -> thm -> int -> tactic   
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  val rewrite_goals_rule: thm list -> thm -> thm
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  val rewrite_rule	: thm list -> thm -> thm
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  val rewrite_goals_tac	: thm list -> tactic
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  val rewrite_tac	: thm list -> tactic
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  val rewtac		: thm -> tactic
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  val rotate_tac	: int -> int -> tactic
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  val rtac		: thm -> int -> tactic
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  val rule_by_tactic	: tactic -> thm -> thm
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  val solve_tac		: thm list -> int -> tactic
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  val subgoal_tac	: string -> int -> tactic
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  val subgoals_tac	: string list -> int -> tactic
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  val subgoals_of_brl	: bool * thm -> int
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  val term_lift_inst_rule	:
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      thm * int * (indexname*typ)list * ((indexname*typ)*term)list  * thm
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      -> thm
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  val thin_tac		: string -> int -> tactic
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  val trace_goalno_tac	: (int -> tactic) -> int -> tactic
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  end;
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structure Tactic : TACTIC = 
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struct
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(*Discover which goal is chosen:  SOMEGOAL(trace_goalno_tac tac) *)
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fun trace_goalno_tac tac i st =  
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    case Seq.pull(tac i st) of
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	None    => Seq.empty
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      | seqcell => (writeln ("Subgoal " ^ string_of_int i ^ " selected"); 
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    			 Seq.make(fn()=> seqcell));
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(*Makes a rule by applying a tactic to an existing rule*)
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fun rule_by_tactic tac rl =
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  let val (st, thaw) = freeze_thaw (zero_var_indexes rl)
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  in case Seq.pull (tac st)  of
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	None        => raise THM("rule_by_tactic", 0, [rl])
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      | Some(st',_) => Thm.varifyT (thaw st')
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  end;
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(*** Basic tactics ***)
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(*Makes a tactic whose effect on a state is given by thmfun: thm->thm seq.*)
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fun PRIMSEQ thmfun st =  thmfun st handle THM _ => Seq.empty;
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(*Makes a tactic whose effect on a state is given by thmfun: thm->thm.*)
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fun PRIMITIVE thmfun = PRIMSEQ (Seq.single o thmfun);
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(*** The following fail if the goal number is out of range:
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     thus (REPEAT (resolve_tac rules i)) stops once subgoal i disappears. *)
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(*Solve subgoal i by assumption*)
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fun assume_tac i = PRIMSEQ (assumption i);
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(*Solve subgoal i by assumption, using no unification*)
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fun eq_assume_tac i = PRIMITIVE (eq_assumption i);
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(** Resolution/matching tactics **)
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(*The composition rule/state: no lifting or var renaming.
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  The arg = (bires_flg, orule, m) ;  see bicompose for explanation.*)
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fun compose_tac arg i = PRIMSEQ (bicompose false arg i);
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(*Converts a "destruct" rule like P&Q==>P to an "elimination" rule
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  like [| P&Q; P==>R |] ==> R *)
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fun make_elim rl = zero_var_indexes (rl RS revcut_rl);
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(*Attack subgoal i by resolution, using flags to indicate elimination rules*)
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fun biresolve_tac brules i = PRIMSEQ (biresolution false brules i);
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(*Resolution: the simple case, works for introduction rules*)
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fun resolve_tac rules = biresolve_tac (map (pair false) rules);
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(*Resolution with elimination rules only*)
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fun eresolve_tac rules = biresolve_tac (map (pair true) rules);
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(*Forward reasoning using destruction rules.*)
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fun forward_tac rls = resolve_tac (map make_elim rls) THEN' assume_tac;
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(*Like forward_tac, but deletes the assumption after use.*)
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fun dresolve_tac rls = eresolve_tac (map make_elim rls);
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(*Shorthand versions: for resolution with a single theorem*)
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fun rtac rl = resolve_tac [rl];
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fun etac rl = eresolve_tac [rl];
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fun dtac rl = dresolve_tac [rl];
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val atac = assume_tac;
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(*Use an assumption or some rules ... A popular combination!*)
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fun ares_tac rules = assume_tac  ORELSE'  resolve_tac rules;
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fun solve_tac rules = resolve_tac rules THEN_ALL_NEW assume_tac;
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(*Matching tactics -- as above, but forbid updating of state*)
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fun bimatch_tac brules i = PRIMSEQ (biresolution true brules i);
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fun match_tac rules  = bimatch_tac (map (pair false) rules);
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fun ematch_tac rules = bimatch_tac (map (pair true) rules);
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fun dmatch_tac rls   = ematch_tac (map make_elim rls);
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(*Smash all flex-flex disagreement pairs in the proof state.*)
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val flexflex_tac = PRIMSEQ flexflex_rule;
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(*Remove duplicate subgoals.  By Mark Staples*)
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local
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fun cterm_aconv (a,b) = #t (rep_cterm a) aconv #t (rep_cterm b);
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in
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fun distinct_subgoals_tac state = 
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    let val (frozth,thawfn) = freeze_thaw state
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	val froz_prems = cprems_of frozth
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	val assumed = implies_elim_list frozth (map assume froz_prems)
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	val implied = implies_intr_list (gen_distinct cterm_aconv froz_prems)
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					assumed;
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    in  Seq.single (thawfn implied)  end
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end; 
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(*Lift and instantiate a rule wrt the given state and subgoal number *)
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fun lift_inst_rule (st, i, sinsts, rule) =
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let val {maxidx,sign,...} = rep_thm st
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    val (_, _, Bi, _) = dest_state(st,i)
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    val params = Logic.strip_params Bi	        (*params of subgoal i*)
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    val params = rev(rename_wrt_term Bi params) (*as they are printed*)
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    val paramTs = map #2 params
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    and inc = maxidx+1
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    fun liftvar (Var ((a,j), T)) = Var((a, j+inc), paramTs---> incr_tvar inc T)
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      | liftvar t = raise TERM("Variable expected", [t]);
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    fun liftterm t = list_abs_free (params, 
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				    Logic.incr_indexes(paramTs,inc) t)
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    (*Lifts instantiation pair over params*)
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    fun liftpair (cv,ct) = (cterm_fun liftvar cv, cterm_fun liftterm ct)
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    fun lifttvar((a,i),ctyp) =
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	let val {T,sign} = rep_ctyp ctyp
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	in  ((a,i+inc), ctyp_of sign (incr_tvar inc T)) end
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    val rts = types_sorts rule and (types,sorts) = types_sorts st
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    fun types'(a,~1) = (case assoc(params,a) of None => types(a,~1) | sm => sm)
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      | types'(ixn) = types ixn;
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    val used = add_term_tvarnames
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                  (#prop(rep_thm st) $ #prop(rep_thm rule),[])
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    val (Tinsts,insts) = read_insts sign rts (types',sorts) used sinsts
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in instantiate (map lifttvar Tinsts, map liftpair insts)
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               (lift_rule (st,i) rule)
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end;
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(*
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Like lift_inst_rule but takes terms, not strings, where the terms may contain
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Bounds referring to parameters of the subgoal.
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insts: [...,(vj,tj),...]
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The tj may contain references to parameters of subgoal i of the state st
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in the form of Bound k, i.e. the tj may be subterms of the subgoal.
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To saturate the lose bound vars, the tj are enclosed in abstractions
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corresponding to the parameters of subgoal i, thus turning them into
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functions. At the same time, the types of the vj are lifted.
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NB: the types in insts must be correctly instantiated already,
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    i.e. Tinsts is not applied to insts.
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*)
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fun term_lift_inst_rule (st, i, Tinsts, insts, rule) =
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let val {maxidx,sign,...} = rep_thm st
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    val (_, _, Bi, _) = dest_state(st,i)
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    val params = Logic.strip_params Bi          (*params of subgoal i*)
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    val paramTs = map #2 params
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    and inc = maxidx+1
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    fun liftvar ((a,j), T) = Var((a, j+inc), paramTs---> incr_tvar inc T)
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    (*lift only Var, not term, which must be lifted already*)
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    fun liftpair (v,t) = (cterm_of sign (liftvar v), cterm_of sign t)
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    fun liftTpair((a,i),T) = ((a,i+inc), ctyp_of sign (incr_tvar inc T))
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in instantiate (map liftTpair Tinsts, map liftpair insts)
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               (lift_rule (st,i) rule)
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end;
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(*** Resolve after lifting and instantation; may refer to parameters of the
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     subgoal.  Fails if "i" is out of range.  ***)
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(*compose version: arguments are as for bicompose.*)
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fun compose_inst_tac sinsts (bires_flg, rule, nsubgoal) i st = st |>
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  (compose_tac (bires_flg, lift_inst_rule (st, i, sinsts, rule), nsubgoal) i
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   handle TERM (msg,_)   => (writeln msg;  no_tac)
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	| THM  (msg,_,_) => (writeln msg;  no_tac));
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(*"Resolve" version.  Note: res_inst_tac cannot behave sensibly if the
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  terms that are substituted contain (term or type) unknowns from the
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  goal, because it is unable to instantiate goal unknowns at the same time.
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  The type checker is instructed not to freeze flexible type vars that
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  were introduced during type inference and still remain in the term at the
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  end.  This increases flexibility but can introduce schematic type vars in
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  goals.
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*)
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fun res_inst_tac sinsts rule i =
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    compose_inst_tac sinsts (false, rule, nprems_of rule) i;
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(*eresolve elimination version*)
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fun eres_inst_tac sinsts rule i =
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    compose_inst_tac sinsts (true, rule, nprems_of rule) i;
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(*For forw_inst_tac and dres_inst_tac.  Preserve Var indexes of rl;
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  increment revcut_rl instead.*)
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fun make_elim_preserve rl = 
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  let val {maxidx,...} = rep_thm rl
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      fun cvar ixn = cterm_of (Theory.sign_of ProtoPure.thy) (Var(ixn,propT));
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      val revcut_rl' = 
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	  instantiate ([],  [(cvar("V",0), cvar("V",maxidx+1)),
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			     (cvar("W",0), cvar("W",maxidx+1))]) revcut_rl
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      val arg = (false, rl, nprems_of rl)
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      val [th] = Seq.list_of (bicompose false arg 1 revcut_rl')
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  in  th  end
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  handle Bind => raise THM("make_elim_preserve", 1, [rl]);
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(*instantiate and cut -- for a FACT, anyway...*)
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fun cut_inst_tac sinsts rule = res_inst_tac sinsts (make_elim_preserve rule);
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(*forward tactic applies a RULE to an assumption without deleting it*)
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fun forw_inst_tac sinsts rule = cut_inst_tac sinsts rule THEN' assume_tac;
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lcp@270
   293
(*dresolve tactic applies a RULE to replace an assumption*)
clasohm@0
   294
fun dres_inst_tac sinsts rule = eres_inst_tac sinsts (make_elim_preserve rule);
clasohm@0
   295
paulson@1951
   296
(*Deletion of an assumption*)
paulson@1951
   297
fun thin_tac s = eres_inst_tac [("V",s)] thin_rl;
paulson@1951
   298
lcp@270
   299
(*** Applications of cut_rl ***)
clasohm@0
   300
clasohm@0
   301
(*Used by metacut_tac*)
clasohm@0
   302
fun bires_cut_tac arg i =
clasohm@1460
   303
    resolve_tac [cut_rl] i  THEN  biresolve_tac arg (i+1) ;
clasohm@0
   304
clasohm@0
   305
(*The conclusion of the rule gets assumed in subgoal i,
clasohm@0
   306
  while subgoal i+1,... are the premises of the rule.*)
clasohm@0
   307
fun metacut_tac rule = bires_cut_tac [(false,rule)];
clasohm@0
   308
clasohm@0
   309
(*Recognizes theorems that are not rules, but simple propositions*)
clasohm@0
   310
fun is_fact rl =
clasohm@0
   311
    case prems_of rl of
clasohm@1460
   312
	[] => true  |  _::_ => false;
clasohm@0
   313
clasohm@0
   314
(*"Cut" all facts from theorem list into the goal as assumptions. *)
clasohm@0
   315
fun cut_facts_tac ths i =
clasohm@0
   316
    EVERY (map (fn th => metacut_tac th i) (filter is_fact ths));
clasohm@0
   317
clasohm@0
   318
(*Introduce the given proposition as a lemma and subgoal*)
paulson@4178
   319
fun subgoal_tac sprop i st = 
wenzelm@4270
   320
  let val st'    = Seq.hd (res_inst_tac [("psi", sprop)] cut_rl i st)
paulson@4178
   321
      val concl' = Logic.strip_assums_concl (List.nth(prems_of st', i))
paulson@4178
   322
  in  
paulson@4178
   323
      if null (term_tvars concl') then ()
paulson@4178
   324
      else warning"Type variables in new subgoal: add a type constraint?";
wenzelm@4270
   325
      Seq.single st'
paulson@4178
   326
  end;
clasohm@0
   327
lcp@439
   328
(*Introduce a list of lemmas and subgoals*)
lcp@439
   329
fun subgoals_tac sprops = EVERY' (map subgoal_tac sprops);
lcp@439
   330
clasohm@0
   331
clasohm@0
   332
(**** Indexing and filtering of theorems ****)
clasohm@0
   333
clasohm@0
   334
(*Returns the list of potentially resolvable theorems for the goal "prem",
clasohm@1460
   335
	using the predicate  could(subgoal,concl).
clasohm@0
   336
  Resulting list is no longer than "limit"*)
clasohm@0
   337
fun filter_thms could (limit, prem, ths) =
clasohm@0
   338
  let val pb = Logic.strip_assums_concl prem;   (*delete assumptions*)
clasohm@0
   339
      fun filtr (limit, []) = []
clasohm@1460
   340
	| filtr (limit, th::ths) =
clasohm@1460
   341
	    if limit=0 then  []
clasohm@1460
   342
	    else if could(pb, concl_of th)  then th :: filtr(limit-1, ths)
clasohm@1460
   343
	    else filtr(limit,ths)
clasohm@0
   344
  in  filtr(limit,ths)  end;
clasohm@0
   345
clasohm@0
   346
clasohm@0
   347
(*** biresolution and resolution using nets ***)
clasohm@0
   348
clasohm@0
   349
(** To preserve the order of the rules, tag them with increasing integers **)
clasohm@0
   350
clasohm@0
   351
(*insert tags*)
clasohm@0
   352
fun taglist k [] = []
clasohm@0
   353
  | taglist k (x::xs) = (k,x) :: taglist (k+1) xs;
clasohm@0
   354
clasohm@0
   355
(*remove tags and suppress duplicates -- list is assumed sorted!*)
clasohm@0
   356
fun untaglist [] = []
clasohm@0
   357
  | untaglist [(k:int,x)] = [x]
clasohm@0
   358
  | untaglist ((k,x) :: (rest as (k',x')::_)) =
clasohm@0
   359
      if k=k' then untaglist rest
clasohm@0
   360
      else    x :: untaglist rest;
clasohm@0
   361
clasohm@0
   362
(*return list elements in original order*)
wenzelm@4438
   363
fun orderlist kbrls = untaglist (sort (int_ord o pairself fst) kbrls); 
clasohm@0
   364
clasohm@0
   365
(*insert one tagged brl into the pair of nets*)
lcp@1077
   366
fun insert_tagged_brl (kbrl as (k,(eres,th)), (inet,enet)) =
clasohm@0
   367
    if eres then 
clasohm@1460
   368
	case prems_of th of
clasohm@1460
   369
	    prem::_ => (inet, Net.insert_term ((prem,kbrl), enet, K false))
clasohm@1460
   370
	  | [] => error"insert_tagged_brl: elimination rule with no premises"
clasohm@0
   371
    else (Net.insert_term ((concl_of th, kbrl), inet, K false), enet);
clasohm@0
   372
clasohm@0
   373
(*build a pair of nets for biresolution*)
lcp@670
   374
fun build_netpair netpair brls = 
lcp@1077
   375
    foldr insert_tagged_brl (taglist 1 brls, netpair);
clasohm@0
   376
paulson@1801
   377
(*delete one kbrl from the pair of nets;
paulson@1801
   378
  we don't know the value of k, so we use 0 and ignore it in the comparison*)
paulson@1801
   379
local
paulson@1801
   380
  fun eq_kbrl ((k,(eres,th)), (k',(eres',th'))) = eq_thm (th,th')
paulson@1801
   381
in
paulson@1801
   382
fun delete_tagged_brl (brl as (eres,th), (inet,enet)) =
paulson@1801
   383
    if eres then 
paulson@1801
   384
	case prems_of th of
paulson@1801
   385
	    prem::_ => (inet, Net.delete_term ((prem, (0,brl)), enet, eq_kbrl))
paulson@2814
   386
	  | []      => (inet,enet)     (*no major premise: ignore*)
paulson@1801
   387
    else (Net.delete_term ((concl_of th, (0,brl)), inet, eq_kbrl), enet);
paulson@1801
   388
end;
paulson@1801
   389
paulson@1801
   390
paulson@3706
   391
(*biresolution using a pair of nets rather than rules.  
paulson@3706
   392
    function "order" must sort and possibly filter the list of brls.
paulson@3706
   393
    boolean "match" indicates matching or unification.*)
paulson@3706
   394
fun biresolution_from_nets_tac order match (inet,enet) =
clasohm@0
   395
  SUBGOAL
clasohm@0
   396
    (fn (prem,i) =>
clasohm@0
   397
      let val hyps = Logic.strip_assums_hyp prem
clasohm@0
   398
          and concl = Logic.strip_assums_concl prem 
clasohm@0
   399
          val kbrls = Net.unify_term inet concl @
paulson@2672
   400
                      List.concat (map (Net.unify_term enet) hyps)
paulson@3706
   401
      in PRIMSEQ (biresolution match (order kbrls) i) end);
clasohm@0
   402
paulson@3706
   403
(*versions taking pre-built nets.  No filtering of brls*)
paulson@3706
   404
val biresolve_from_nets_tac = biresolution_from_nets_tac orderlist false;
paulson@3706
   405
val bimatch_from_nets_tac   = biresolution_from_nets_tac orderlist true;
clasohm@0
   406
clasohm@0
   407
(*fast versions using nets internally*)
lcp@670
   408
val net_biresolve_tac =
lcp@670
   409
    biresolve_from_nets_tac o build_netpair(Net.empty,Net.empty);
lcp@670
   410
lcp@670
   411
val net_bimatch_tac =
lcp@670
   412
    bimatch_from_nets_tac o build_netpair(Net.empty,Net.empty);
clasohm@0
   413
clasohm@0
   414
(*** Simpler version for resolve_tac -- only one net, and no hyps ***)
clasohm@0
   415
clasohm@0
   416
(*insert one tagged rl into the net*)
clasohm@0
   417
fun insert_krl (krl as (k,th), net) =
clasohm@0
   418
    Net.insert_term ((concl_of th, krl), net, K false);
clasohm@0
   419
clasohm@0
   420
(*build a net of rules for resolution*)
clasohm@0
   421
fun build_net rls = 
clasohm@0
   422
    foldr insert_krl (taglist 1 rls, Net.empty);
clasohm@0
   423
clasohm@0
   424
(*resolution using a net rather than rules; pred supports filt_resolve_tac*)
clasohm@0
   425
fun filt_resolution_from_net_tac match pred net =
clasohm@0
   426
  SUBGOAL
clasohm@0
   427
    (fn (prem,i) =>
clasohm@0
   428
      let val krls = Net.unify_term net (Logic.strip_assums_concl prem)
clasohm@0
   429
      in 
clasohm@1460
   430
	 if pred krls  
clasohm@0
   431
         then PRIMSEQ
clasohm@1460
   432
		(biresolution match (map (pair false) (orderlist krls)) i)
clasohm@0
   433
         else no_tac
clasohm@0
   434
      end);
clasohm@0
   435
clasohm@0
   436
(*Resolve the subgoal using the rules (making a net) unless too flexible,
clasohm@0
   437
   which means more than maxr rules are unifiable.      *)
clasohm@0
   438
fun filt_resolve_tac rules maxr = 
clasohm@0
   439
    let fun pred krls = length krls <= maxr
clasohm@0
   440
    in  filt_resolution_from_net_tac false pred (build_net rules)  end;
clasohm@0
   441
clasohm@0
   442
(*versions taking pre-built nets*)
clasohm@0
   443
val resolve_from_net_tac = filt_resolution_from_net_tac false (K true);
clasohm@0
   444
val match_from_net_tac = filt_resolution_from_net_tac true (K true);
clasohm@0
   445
clasohm@0
   446
(*fast versions using nets internally*)
clasohm@0
   447
val net_resolve_tac = resolve_from_net_tac o build_net;
clasohm@0
   448
val net_match_tac = match_from_net_tac o build_net;
clasohm@0
   449
clasohm@0
   450
clasohm@0
   451
(*** For Natural Deduction using (bires_flg, rule) pairs ***)
clasohm@0
   452
clasohm@0
   453
(*The number of new subgoals produced by the brule*)
lcp@1077
   454
fun subgoals_of_brl (true,rule)  = nprems_of rule - 1
lcp@1077
   455
  | subgoals_of_brl (false,rule) = nprems_of rule;
clasohm@0
   456
clasohm@0
   457
(*Less-than test: for sorting to minimize number of new subgoals*)
clasohm@0
   458
fun lessb (brl1,brl2) = subgoals_of_brl brl1 < subgoals_of_brl brl2;
clasohm@0
   459
clasohm@0
   460
clasohm@0
   461
(*** Meta-Rewriting Tactics ***)
clasohm@0
   462
clasohm@0
   463
fun result1 tacf mss thm =
wenzelm@4270
   464
  apsome fst (Seq.pull (tacf mss thm));
clasohm@0
   465
wenzelm@3575
   466
val simple_prover =
wenzelm@3575
   467
  result1 (fn mss => ALLGOALS (resolve_tac (prems_of_mss mss)));
wenzelm@3575
   468
wenzelm@3575
   469
val rewrite_rule = Drule.rewrite_rule_aux simple_prover;
wenzelm@3575
   470
val rewrite_goals_rule = Drule.rewrite_goals_rule_aux simple_prover;
wenzelm@3575
   471
wenzelm@3575
   472
paulson@2145
   473
(*Rewrite subgoal i only.  SELECT_GOAL avoids inefficiencies in goals_conv.*)
paulson@2145
   474
fun asm_rewrite_goal_tac mode prover_tac mss =
paulson@2145
   475
      SELECT_GOAL 
paulson@2145
   476
        (PRIMITIVE
paulson@2145
   477
	   (rewrite_goal_rule mode (result1 prover_tac) mss 1));
clasohm@0
   478
lcp@69
   479
(*Rewrite throughout proof state. *)
lcp@69
   480
fun rewrite_tac defs = PRIMITIVE(rewrite_rule defs);
clasohm@0
   481
clasohm@0
   482
(*Rewrite subgoals only, not main goal. *)
lcp@69
   483
fun rewrite_goals_tac defs = PRIMITIVE (rewrite_goals_rule defs);
clasohm@0
   484
clasohm@1460
   485
fun rewtac def = rewrite_goals_tac [def];
clasohm@0
   486
clasohm@0
   487
paulson@1501
   488
(*** for folding definitions, handling critical pairs ***)
lcp@69
   489
lcp@69
   490
(*The depth of nesting in a term*)
lcp@69
   491
fun term_depth (Abs(a,T,t)) = 1 + term_depth t
paulson@2145
   492
  | term_depth (f$t) = 1 + Int.max(term_depth f, term_depth t)
lcp@69
   493
  | term_depth _ = 0;
lcp@69
   494
lcp@69
   495
val lhs_of_thm = #1 o Logic.dest_equals o #prop o rep_thm;
lcp@69
   496
lcp@69
   497
(*folding should handle critical pairs!  E.g. K == Inl(0),  S == Inr(Inl(0))
lcp@69
   498
  Returns longest lhs first to avoid folding its subexpressions.*)
lcp@69
   499
fun sort_lhs_depths defs =
lcp@69
   500
  let val keylist = make_keylist (term_depth o lhs_of_thm) defs
wenzelm@4438
   501
      val keys = distinct (sort (rev_order o int_ord) (map #2 keylist))
lcp@69
   502
  in  map (keyfilter keylist) keys  end;
lcp@69
   503
lcp@69
   504
fun fold_tac defs = EVERY 
lcp@69
   505
    (map rewrite_tac (sort_lhs_depths (map symmetric defs)));
lcp@69
   506
lcp@69
   507
fun fold_goals_tac defs = EVERY 
lcp@69
   508
    (map rewrite_goals_tac (sort_lhs_depths (map symmetric defs)));
lcp@69
   509
lcp@69
   510
lcp@69
   511
(*** Renaming of parameters in a subgoal
lcp@69
   512
     Names may contain letters, digits or primes and must be
lcp@69
   513
     separated by blanks ***)
clasohm@0
   514
clasohm@0
   515
(*Calling this will generate the warning "Same as previous level" since
clasohm@0
   516
  it affects nothing but the names of bound variables!*)
clasohm@0
   517
fun rename_tac str i = 
wenzelm@4693
   518
  let val cs = Symbol.explode str 
clasohm@0
   519
  in  
clasohm@0
   520
  if !Logic.auto_rename 
wenzelm@4213
   521
  then (warning "Resetting Logic.auto_rename"; 
clasohm@1460
   522
	Logic.auto_rename := false)
clasohm@0
   523
  else ();
wenzelm@4693
   524
  case #2 (take_prefix (Symbol.is_letdig orf Symbol.is_blank) cs) of
wenzelm@4693
   525
      [] => PRIMITIVE (rename_params_rule (scanwords Symbol.is_letdig cs, i))
clasohm@0
   526
    | c::_ => error ("Illegal character: " ^ c)
clasohm@0
   527
  end;
clasohm@0
   528
paulson@1501
   529
(*Rename recent parameters using names generated from a and the suffixes,
paulson@1501
   530
  provided the string a, which represents a term, is an identifier. *)
clasohm@0
   531
fun rename_last_tac a sufs i = 
clasohm@0
   532
  let val names = map (curry op^ a) sufs
clasohm@0
   533
  in  if Syntax.is_identifier a
clasohm@0
   534
      then PRIMITIVE (rename_params_rule (names,i))
clasohm@0
   535
      else all_tac
clasohm@0
   536
  end;
clasohm@0
   537
paulson@2043
   538
(*Prunes all redundant parameters from the proof state by rewriting.
paulson@2043
   539
  DOES NOT rewrite main goal, where quantification over an unused bound
paulson@2043
   540
    variable is sometimes done to avoid the need for cut_facts_tac.*)
paulson@2043
   541
val prune_params_tac = rewrite_goals_tac [triv_forall_equality];
clasohm@0
   542
paulson@1501
   543
(*rotate_tac n i: rotate the assumptions of subgoal i by n positions, from
paulson@1501
   544
  right to left if n is positive, and from left to right if n is negative.*)
paulson@2672
   545
fun rotate_tac 0 i = all_tac
paulson@2672
   546
  | rotate_tac k i = PRIMITIVE (rotate_rule k i);
nipkow@1209
   547
paulson@7248
   548
(*Rotates the given subgoal to be the last.*)
paulson@7248
   549
fun defer_tac i = PRIMITIVE (permute_prems (i-1) 1);
paulson@7248
   550
nipkow@5974
   551
(* remove premises that do not satisfy p; fails if all prems satisfy p *)
nipkow@5974
   552
fun filter_prems_tac p =
nipkow@5974
   553
  let fun Then None tac = Some tac
nipkow@5974
   554
        | Then (Some tac) tac' = Some(tac THEN' tac');
nipkow@5974
   555
      fun thins ((tac,n),H) =
nipkow@5974
   556
        if p H then (tac,n+1)
nipkow@5974
   557
        else (Then tac (rotate_tac n THEN' etac thin_rl),0);
nipkow@5974
   558
  in SUBGOAL(fn (subg,n) =>
nipkow@5974
   559
       let val Hs = Logic.strip_assums_hyp subg
nipkow@5974
   560
       in case fst(foldl thins ((None,0),Hs)) of
nipkow@5974
   561
            None => no_tac | Some tac => tac n
nipkow@5974
   562
       end)
nipkow@5974
   563
  end;
nipkow@5974
   564
clasohm@0
   565
end;
paulson@1501
   566
paulson@1501
   567
open Tactic;