src/Pure/meta_simplifier.ML
author wenzelm
Sat Jul 08 12:54:45 2006 +0200 (2006-07-08)
changeset 20057 058e913bac71
parent 20028 b9752164ad92
child 20079 ec5c8584487c
permissions -rw-r--r--
tuned exception handling;
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(*  Title:      Pure/meta_simplifier.ML
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    ID:         $Id$
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    Author:     Tobias Nipkow and Stefan Berghofer
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Meta-level Simplification.
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*)
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infix 4
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  addsimps delsimps addeqcongs deleqcongs addcongs delcongs addsimprocs delsimprocs
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  setmksimps setmkcong setmksym setmkeqTrue settermless setsubgoaler
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  setloop' setloop addloop addloop' delloop setSSolver addSSolver setSolver addSolver;
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signature BASIC_META_SIMPLIFIER =
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sig
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  val debug_simp: bool ref
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  val trace_simp: bool ref
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  val simp_depth_limit: int ref
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  val trace_simp_depth_limit: int ref
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  type rrule
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  val eq_rrule: rrule * rrule -> bool
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  type cong
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  type simpset
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  type proc
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  type solver
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  val mk_solver': string -> (simpset -> int -> tactic) -> solver
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  val mk_solver: string -> (thm list -> int -> tactic) -> solver
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  val rep_ss: simpset ->
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   {rules: rrule Net.net,
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    prems: thm list,
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    bounds: int * ((string * typ) * string) list,
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    context: Context.proof option} *
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   {congs: (string * cong) list * string list,
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    procs: proc Net.net,
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    mk_rews:
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     {mk: thm -> thm list,
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      mk_cong: thm -> thm,
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      mk_sym: thm -> thm option,
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      mk_eq_True: thm -> thm option,
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      reorient: theory -> term list -> term -> term -> bool},
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    termless: term * term -> bool,
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    subgoal_tac: simpset -> int -> tactic,
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    loop_tacs: (string * (simpset -> int -> tactic)) list,
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    solvers: solver list * solver list}
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  val print_ss: simpset -> unit
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  val empty_ss: simpset
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  val merge_ss: simpset * simpset -> simpset
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  type simproc
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  val mk_simproc: string -> cterm list ->
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    (theory -> simpset -> term -> thm option) -> simproc
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  val add_prems: thm list -> simpset -> simpset
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  val prems_of_ss: simpset -> thm list
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  val addsimps: simpset * thm list -> simpset
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  val delsimps: simpset * thm list -> simpset
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  val addeqcongs: simpset * thm list -> simpset
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  val deleqcongs: simpset * thm list -> simpset
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  val addcongs: simpset * thm list -> simpset
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  val delcongs: simpset * thm list -> simpset
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  val addsimprocs: simpset * simproc list -> simpset
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  val delsimprocs: simpset * simproc list -> simpset
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  val setmksimps: simpset * (thm -> thm list) -> simpset
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  val setmkcong: simpset * (thm -> thm) -> simpset
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  val setmksym: simpset * (thm -> thm option) -> simpset
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  val setmkeqTrue: simpset * (thm -> thm option) -> simpset
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  val settermless: simpset * (term * term -> bool) -> simpset
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  val setsubgoaler: simpset * (simpset -> int -> tactic) -> simpset
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  val setloop': simpset * (simpset -> int -> tactic) -> simpset
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  val setloop: simpset * (int -> tactic) -> simpset
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  val addloop': simpset * (string * (simpset -> int -> tactic)) -> simpset
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  val addloop: simpset * (string * (int -> tactic)) -> simpset
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  val delloop: simpset * string -> simpset
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  val setSSolver: simpset * solver -> simpset
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  val addSSolver: simpset * solver -> simpset
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  val setSolver: simpset * solver -> simpset
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  val addSolver: simpset * solver -> simpset
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end;
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signature META_SIMPLIFIER =
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sig
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  include BASIC_META_SIMPLIFIER
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  exception SIMPLIFIER of string * thm
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  val solver: simpset -> solver -> int -> tactic
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  val clear_ss: simpset -> simpset
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  exception SIMPROC_FAIL of string * exn
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  val simproc_i: theory -> string -> term list
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    -> (theory -> simpset -> term -> thm option) -> simproc
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  val simproc: theory -> string -> string list
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    -> (theory -> simpset -> term -> thm option) -> simproc
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  val inherit_context: simpset -> simpset -> simpset
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  val the_context: simpset -> Context.proof
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  val context: Context.proof -> simpset -> simpset
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  val theory_context: theory  -> simpset -> simpset
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  val debug_bounds: bool ref
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  val set_reorient: (theory -> term list -> term -> term -> bool) -> simpset -> simpset
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  val set_solvers: solver list -> simpset -> simpset
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  val rewrite_cterm: bool * bool * bool ->
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    (simpset -> thm -> thm option) -> simpset -> cterm -> thm
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  val rewrite_aux: (simpset -> thm -> thm option) -> bool -> thm list -> cterm -> thm
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  val simplify_aux: (simpset -> thm -> thm option) -> bool -> thm list -> thm -> thm
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  val rewrite_term: theory -> thm list -> (term -> term option) list -> term -> term
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  val rewrite_thm: bool * bool * bool ->
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    (simpset -> thm -> thm option) -> simpset -> thm -> thm
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  val rewrite_goals_rule_aux: (simpset -> thm -> thm option) -> thm list -> thm -> thm
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  val rewrite_goal_rule: bool * bool * bool ->
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    (simpset -> thm -> thm option) -> simpset -> int -> thm -> thm
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end;
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structure MetaSimplifier: META_SIMPLIFIER =
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struct
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(** datatype simpset **)
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(* rewrite rules *)
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type rrule = {thm: thm, name: string, lhs: term, elhs: cterm, fo: bool, perm: bool};
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(*thm: the rewrite rule;
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  name: name of theorem from which rewrite rule was extracted;
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  lhs: the left-hand side;
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  elhs: the etac-contracted lhs;
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  fo: use first-order matching;
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  perm: the rewrite rule is permutative;
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Remarks:
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  - elhs is used for matching,
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    lhs only for preservation of bound variable names;
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  - fo is set iff
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    either elhs is first-order (no Var is applied),
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      in which case fo-matching is complete,
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    or elhs is not a pattern,
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      in which case there is nothing better to do;*)
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fun eq_rrule ({thm = thm1, ...}: rrule, {thm = thm2, ...}: rrule) =
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  Drule.eq_thm_prop (thm1, thm2);
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(* congruences *)
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type cong = {thm: thm, lhs: cterm};
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fun eq_cong ({thm = thm1, ...}: cong, {thm = thm2, ...}: cong) =
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  Drule.eq_thm_prop (thm1, thm2);
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(* simplification sets, procedures, and solvers *)
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(*A simpset contains data required during conversion:
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    rules: discrimination net of rewrite rules;
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    prems: current premises;
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    bounds: maximal index of bound variables already used
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      (for generating new names when rewriting under lambda abstractions);
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    congs: association list of congruence rules and
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           a list of `weak' congruence constants.
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           A congruence is `weak' if it avoids normalization of some argument.
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    procs: discrimination net of simplification procedures
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      (functions that prove rewrite rules on the fly);
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    mk_rews:
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      mk: turn simplification thms into rewrite rules;
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      mk_cong: prepare congruence rules;
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      mk_sym: turn == around;
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      mk_eq_True: turn P into P == True;
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    termless: relation for ordered rewriting;*)
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type mk_rews =
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 {mk: thm -> thm list,
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  mk_cong: thm -> thm,
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  mk_sym: thm -> thm option,
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  mk_eq_True: thm -> thm option,
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  reorient: theory -> term list -> term -> term -> bool};
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datatype simpset =
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  Simpset of
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   {rules: rrule Net.net,
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    prems: thm list,
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    bounds: int * ((string * typ) * string) list,
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    context: Context.proof option} *
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   {congs: (string * cong) list * string list,
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    procs: proc Net.net,
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    mk_rews: mk_rews,
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    termless: term * term -> bool,
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    subgoal_tac: simpset -> int -> tactic,
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    loop_tacs: (string * (simpset -> int -> tactic)) list,
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    solvers: solver list * solver list}
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and proc =
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  Proc of
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   {name: string,
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    lhs: cterm,
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    proc: theory -> simpset -> term -> thm option,
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    id: stamp}
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and solver =
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  Solver of
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   {name: string,
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    solver: simpset -> int -> tactic,
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    id: stamp};
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fun rep_ss (Simpset args) = args;
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fun make_ss1 (rules, prems, bounds, context) =
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  {rules = rules, prems = prems, bounds = bounds, context = context};
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fun map_ss1 f {rules, prems, bounds, context} =
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  make_ss1 (f (rules, prems, bounds, context));
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fun make_ss2 (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers) =
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  {congs = congs, procs = procs, mk_rews = mk_rews, termless = termless,
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    subgoal_tac = subgoal_tac, loop_tacs = loop_tacs, solvers = solvers};
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fun map_ss2 f {congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers} =
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  make_ss2 (f (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers));
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fun make_simpset (args1, args2) = Simpset (make_ss1 args1, make_ss2 args2);
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fun map_simpset f (Simpset ({rules, prems, bounds, context},
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    {congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers})) =
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  make_simpset (f ((rules, prems, bounds, context),
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    (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers)));
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fun map_simpset1 f (Simpset (r1, r2)) = Simpset (map_ss1 f r1, r2);
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fun map_simpset2 f (Simpset (r1, r2)) = Simpset (r1, map_ss2 f r2);
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fun prems_of_ss (Simpset ({prems, ...}, _)) = prems;
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fun eq_proc (Proc {id = id1, ...}, Proc {id = id2, ...}) = (id1 = id2);
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fun mk_solver' name solver = Solver {name = name, solver = solver, id = stamp ()};
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fun mk_solver name solver = mk_solver' name (solver o prems_of_ss);
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fun solver_name (Solver {name, ...}) = name;
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fun solver ss (Solver {solver = tac, ...}) = tac ss;
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fun eq_solver (Solver {id = id1, ...}, Solver {id = id2, ...}) = (id1 = id2);
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val merge_solvers = gen_merge_lists eq_solver;
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(* diagnostics *)
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exception SIMPLIFIER of string * thm;
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val debug_simp = ref false;
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val trace_simp = ref false;
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val simp_depth = ref 0;
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val simp_depth_limit = ref 100;
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val trace_simp_depth_limit = ref 1;
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val trace_simp_depth_limit_exceeded = ref false;
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local
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fun println a =
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  if ! simp_depth > ! trace_simp_depth_limit
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  then if !trace_simp_depth_limit_exceeded then ()
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       else (tracing "trace_simp_depth_limit exceeded!";
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             trace_simp_depth_limit_exceeded := true)
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  else (tracing (enclose "[" "]" (string_of_int (! simp_depth)) ^ a);
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        trace_simp_depth_limit_exceeded := false);
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fun prnt warn a = if warn then warning a else println a;
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fun show_bounds (Simpset ({bounds = (_, bs), ...}, _)) t =
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  let
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    val used = Term.add_term_names (t, []);
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    val xs = rev (Term.variantlist (rev (map #2 bs), used));
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    fun subst (((b, T), _), x') = (Free (b, T), Syntax.mark_boundT (x', T));
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  in Term.subst_atomic (ListPair.map subst (bs, xs)) t end;
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in
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fun print_term warn a ss thy t = prnt warn (a ^ "\n" ^
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  Sign.string_of_term thy (if ! debug_simp then t else show_bounds ss t));
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fun debug warn a = if ! debug_simp then prnt warn a else ();
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fun trace warn a = if ! trace_simp then prnt warn a else ();
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fun debug_term warn a ss thy t = if ! debug_simp then print_term warn a ss thy t else ();
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fun trace_term warn a ss thy t = if ! trace_simp then print_term warn a ss thy t else ();
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fun trace_cterm warn a ss ct =
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  if ! trace_simp then print_term warn a ss (Thm.theory_of_cterm ct) (Thm.term_of ct) else ();
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fun trace_thm a ss th =
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  if ! trace_simp then print_term false a ss (Thm.theory_of_thm th) (Thm.full_prop_of th) else ();
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fun trace_named_thm a ss (th, name) =
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  if ! trace_simp then
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    print_term false (if name = "" then a else a ^ " " ^ quote name ^ ":") ss
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      (Thm.theory_of_thm th) (Thm.full_prop_of th)
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  else ();
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fun warn_thm a ss th = print_term true a ss (Thm.theory_of_thm th) (Thm.full_prop_of th);
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fun cond_warn_thm a (ss as Simpset ({context, ...}, _)) th =
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  if is_some context then () else warn_thm a ss th; 
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end;
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(* print simpsets *)
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fun print_ss ss =
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  let
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    val pretty_thms = map Display.pretty_thm;
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    fun pretty_cong (name, th) =
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      Pretty.block [Pretty.str (name ^ ":"), Pretty.brk 1, Display.pretty_thm th];
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    fun pretty_proc (name, lhss) =
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      Pretty.big_list (name ^ ":") (map Display.pretty_cterm lhss);
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    val Simpset ({rules, ...}, {congs, procs, loop_tacs, solvers, ...}) = ss;
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    val smps = map #thm (Net.entries rules);
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    val cngs = map (fn (name, {thm, ...}) => (name, thm)) (#1 congs);
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    val prcs = Net.entries procs |>
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      map (fn Proc {name, lhs, id, ...} => ((name, lhs), id))
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      |> partition_eq (eq_snd (op =))
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      |> map (fn ps => (fst (fst (hd ps)), map (snd o fst) ps))
wenzelm@17756
   314
      |> Library.sort_wrt fst;
wenzelm@15023
   315
  in
wenzelm@15034
   316
    [Pretty.big_list "simplification rules:" (pretty_thms smps),
wenzelm@15034
   317
      Pretty.big_list "simplification procedures:" (map pretty_proc prcs),
wenzelm@15034
   318
      Pretty.big_list "congruences:" (map pretty_cong cngs),
wenzelm@15088
   319
      Pretty.strs ("loopers:" :: map (quote o #1) loop_tacs),
wenzelm@15088
   320
      Pretty.strs ("unsafe solvers:" :: map (quote o solver_name) (#1 solvers)),
wenzelm@15088
   321
      Pretty.strs ("safe solvers:" :: map (quote o solver_name) (#2 solvers))]
wenzelm@15023
   322
    |> Pretty.chunks |> Pretty.writeln
nipkow@13828
   323
  end;
berghofe@10413
   324
wenzelm@15023
   325
wenzelm@15023
   326
(* simprocs *)
wenzelm@15023
   327
wenzelm@15023
   328
exception SIMPROC_FAIL of string * exn;
wenzelm@15023
   329
wenzelm@15023
   330
datatype simproc = Simproc of proc list;
wenzelm@15023
   331
wenzelm@15023
   332
fun mk_simproc name lhss proc =
wenzelm@15023
   333
  let val id = stamp () in
wenzelm@15023
   334
    Simproc (lhss |> map (fn lhs =>
wenzelm@15023
   335
      Proc {name = name, lhs = lhs, proc = proc, id = id}))
wenzelm@15023
   336
  end;
wenzelm@15023
   337
wenzelm@19798
   338
(* FIXME avoid global thy and Logic.varify *)
wenzelm@16458
   339
fun simproc_i thy name = mk_simproc name o map (Thm.cterm_of thy o Logic.varify);
wenzelm@16807
   340
fun simproc thy name = simproc_i thy name o map (Sign.read_term thy);
wenzelm@15023
   341
skalberg@15011
   342
berghofe@10413
   343
berghofe@10413
   344
(** simpset operations **)
berghofe@10413
   345
wenzelm@17882
   346
(* context *)
berghofe@10413
   347
wenzelm@17614
   348
fun eq_bound (x: string, (y, _)) = x = y;
wenzelm@17614
   349
wenzelm@17882
   350
fun add_bound bound = map_simpset1 (fn (rules, prems, (count, bounds), context) =>
wenzelm@17882
   351
  (rules, prems, (count + 1, bound :: bounds), context));
wenzelm@17882
   352
wenzelm@17882
   353
fun add_prems ths = map_simpset1 (fn (rules, prems, bounds, context) =>
wenzelm@17882
   354
  (rules, ths @ prems, bounds, context));
wenzelm@17882
   355
wenzelm@17882
   356
fun inherit_context (Simpset ({bounds, context, ...}, _)) =
wenzelm@17882
   357
  map_simpset1 (fn (rules, prems, _, _) => (rules, prems, bounds, context));
wenzelm@16985
   358
wenzelm@17882
   359
fun the_context (Simpset ({context = SOME ctxt, ...}, _)) = ctxt
wenzelm@17882
   360
  | the_context _ = raise Fail "Simplifier: no proof context in simpset";
berghofe@10413
   361
wenzelm@17897
   362
fun context ctxt =
wenzelm@17882
   363
  map_simpset1 (fn (rules, prems, bounds, _) => (rules, prems, bounds, SOME ctxt));
wenzelm@17882
   364
wenzelm@17897
   365
val theory_context = context o Context.init_proof;
wenzelm@17897
   366
wenzelm@17882
   367
fun fallback_context _ (ss as Simpset ({context = SOME _, ...}, _)) = ss
wenzelm@17882
   368
  | fallback_context thy ss =
wenzelm@17882
   369
     (warning "Simplifier: no proof context in simpset -- fallback to theory context!";
wenzelm@17897
   370
      theory_context thy ss);
wenzelm@17897
   371
wenzelm@17897
   372
wenzelm@20028
   373
(* maintain simp rules *)
berghofe@10413
   374
wenzelm@15023
   375
fun mk_rrule2 {thm, name, lhs, elhs, perm} =
wenzelm@15023
   376
  let
wenzelm@15023
   377
    val fo = Pattern.first_order (term_of elhs) orelse not (Pattern.pattern (term_of elhs))
wenzelm@15023
   378
  in {thm = thm, name = name, lhs = lhs, elhs = elhs, fo = fo, perm = perm} end;
berghofe@10413
   379
wenzelm@20028
   380
fun del_rrule (rrule as {thm, elhs, ...}) ss =
wenzelm@20028
   381
  ss |> map_simpset1 (fn (rules, prems, bounds, context) =>
wenzelm@20028
   382
    (Net.delete_term eq_rrule (term_of elhs, rrule) rules, prems, bounds, context))
wenzelm@20028
   383
  handle Net.DELETE => (cond_warn_thm "Rewrite rule not in simpset:" ss thm; ss);
wenzelm@20028
   384
wenzelm@20028
   385
fun insert_rrule (rrule as {thm, name, lhs, elhs, perm}) ss =
wenzelm@16985
   386
 (trace_named_thm "Adding rewrite rule" ss (thm, name);
wenzelm@17882
   387
  ss |> map_simpset1 (fn (rules, prems, bounds, context) =>
wenzelm@15023
   388
    let
wenzelm@15023
   389
      val rrule2 as {elhs, ...} = mk_rrule2 rrule;
wenzelm@16807
   390
      val rules' = Net.insert_term eq_rrule (term_of elhs, rrule2) rules;
wenzelm@17882
   391
    in (rules', prems, bounds, context) end)
wenzelm@20028
   392
  handle Net.INSERT => (cond_warn_thm "Ignoring duplicate rewrite rule:" ss thm; ss));
berghofe@10413
   393
berghofe@10413
   394
fun vperm (Var _, Var _) = true
berghofe@10413
   395
  | vperm (Abs (_, _, s), Abs (_, _, t)) = vperm (s, t)
berghofe@10413
   396
  | vperm (t1 $ t2, u1 $ u2) = vperm (t1, u1) andalso vperm (t2, u2)
berghofe@10413
   397
  | vperm (t, u) = (t = u);
berghofe@10413
   398
berghofe@10413
   399
fun var_perm (t, u) =
wenzelm@19303
   400
  vperm (t, u) andalso gen_eq_set (op =) (term_varnames t, term_varnames u);
berghofe@10413
   401
berghofe@10413
   402
(* FIXME: it seems that the conditions on extra variables are too liberal if
berghofe@10413
   403
prems are nonempty: does solving the prems really guarantee instantiation of
berghofe@10413
   404
all its Vars? Better: a dynamic check each time a rule is applied.
berghofe@10413
   405
*)
berghofe@10413
   406
fun rewrite_rule_extra_vars prems elhs erhs =
wenzelm@16861
   407
  not (term_varnames erhs subset fold add_term_varnames prems (term_varnames elhs))
berghofe@10413
   408
  orelse
wenzelm@19482
   409
  not (term_tvars erhs subset (term_tvars elhs union maps term_tvars prems));
berghofe@10413
   410
wenzelm@15023
   411
(*simple test for looping rewrite rules and stupid orientations*)
wenzelm@18208
   412
fun default_reorient thy prems lhs rhs =
wenzelm@15023
   413
  rewrite_rule_extra_vars prems lhs rhs
wenzelm@15023
   414
    orelse
wenzelm@15023
   415
  is_Var (head_of lhs)
wenzelm@15023
   416
    orelse
nipkow@16305
   417
(* turns t = x around, which causes a headache if x is a local variable -
nipkow@16305
   418
   usually it is very useful :-(
nipkow@16305
   419
  is_Free rhs andalso not(is_Free lhs) andalso not(Logic.occs(rhs,lhs))
nipkow@16305
   420
  andalso not(exists_subterm is_Var lhs)
nipkow@16305
   421
    orelse
nipkow@16305
   422
*)
wenzelm@16842
   423
  exists (fn t => Logic.occs (lhs, t)) (rhs :: prems)
wenzelm@15023
   424
    orelse
wenzelm@17203
   425
  null prems andalso Pattern.matches thy (lhs, rhs)
berghofe@10413
   426
    (*the condition "null prems" is necessary because conditional rewrites
berghofe@10413
   427
      with extra variables in the conditions may terminate although
wenzelm@15023
   428
      the rhs is an instance of the lhs; example: ?m < ?n ==> f(?n) == f(?m)*)
wenzelm@15023
   429
    orelse
wenzelm@15023
   430
  is_Const lhs andalso not (is_Const rhs);
berghofe@10413
   431
berghofe@10413
   432
fun decomp_simp thm =
wenzelm@15023
   433
  let
wenzelm@16458
   434
    val {thy, prop, ...} = Thm.rep_thm thm;
wenzelm@15023
   435
    val prems = Logic.strip_imp_prems prop;
wenzelm@15023
   436
    val concl = Drule.strip_imp_concl (Thm.cprop_of thm);
wenzelm@15023
   437
    val (lhs, rhs) = Drule.dest_equals concl handle TERM _ =>
wenzelm@15023
   438
      raise SIMPLIFIER ("Rewrite rule not a meta-equality", thm);
wenzelm@15023
   439
    val (_, elhs) = Drule.dest_equals (Thm.cprop_of (Thm.eta_conversion lhs));
wenzelm@16665
   440
    val elhs = if term_of elhs aconv term_of lhs then lhs else elhs;  (*share identical copies*)
wenzelm@18929
   441
    val erhs = Envir.eta_contract (term_of rhs);
wenzelm@15023
   442
    val perm =
wenzelm@15023
   443
      var_perm (term_of elhs, erhs) andalso
wenzelm@15023
   444
      not (term_of elhs aconv erhs) andalso
wenzelm@15023
   445
      not (is_Var (term_of elhs));
wenzelm@16458
   446
  in (thy, prems, term_of lhs, elhs, term_of rhs, perm) end;
berghofe@10413
   447
wenzelm@12783
   448
fun decomp_simp' thm =
wenzelm@12979
   449
  let val (_, _, lhs, _, rhs, _) = decomp_simp thm in
wenzelm@12783
   450
    if Thm.nprems_of thm > 0 then raise SIMPLIFIER ("Bad conditional rewrite rule", thm)
wenzelm@12979
   451
    else (lhs, rhs)
wenzelm@12783
   452
  end;
wenzelm@12783
   453
wenzelm@15023
   454
fun mk_eq_True (Simpset (_, {mk_rews = {mk_eq_True, ...}, ...})) (thm, name) =
wenzelm@15023
   455
  (case mk_eq_True thm of
skalberg@15531
   456
    NONE => []
skalberg@15531
   457
  | SOME eq_True =>
wenzelm@15023
   458
      let val (_, _, lhs, elhs, _, _) = decomp_simp eq_True
wenzelm@15023
   459
      in [{thm = eq_True, name = name, lhs = lhs, elhs = elhs, perm = false}] end);
berghofe@10413
   460
wenzelm@15023
   461
(*create the rewrite rule and possibly also the eq_True variant,
wenzelm@15023
   462
  in case there are extra vars on the rhs*)
wenzelm@15023
   463
fun rrule_eq_True (thm, name, lhs, elhs, rhs, ss, thm2) =
wenzelm@15023
   464
  let val rrule = {thm = thm, name = name, lhs = lhs, elhs = elhs, perm = false} in
wenzelm@15023
   465
    if term_varnames rhs subset term_varnames lhs andalso
wenzelm@15023
   466
      term_tvars rhs subset term_tvars lhs then [rrule]
wenzelm@15023
   467
    else mk_eq_True ss (thm2, name) @ [rrule]
berghofe@10413
   468
  end;
berghofe@10413
   469
wenzelm@15023
   470
fun mk_rrule ss (thm, name) =
wenzelm@15023
   471
  let val (_, prems, lhs, elhs, rhs, perm) = decomp_simp thm in
wenzelm@15023
   472
    if perm then [{thm = thm, name = name, lhs = lhs, elhs = elhs, perm = true}]
wenzelm@15023
   473
    else
wenzelm@15023
   474
      (*weak test for loops*)
wenzelm@15023
   475
      if rewrite_rule_extra_vars prems lhs rhs orelse is_Var (term_of elhs)
wenzelm@15023
   476
      then mk_eq_True ss (thm, name)
wenzelm@15023
   477
      else rrule_eq_True (thm, name, lhs, elhs, rhs, ss, thm)
berghofe@10413
   478
  end;
berghofe@10413
   479
wenzelm@15023
   480
fun orient_rrule ss (thm, name) =
wenzelm@18208
   481
  let
wenzelm@18208
   482
    val (thy, prems, lhs, elhs, rhs, perm) = decomp_simp thm;
wenzelm@18208
   483
    val Simpset (_, {mk_rews = {reorient, mk_sym, ...}, ...}) = ss;
wenzelm@18208
   484
  in
wenzelm@15023
   485
    if perm then [{thm = thm, name = name, lhs = lhs, elhs = elhs, perm = true}]
wenzelm@16458
   486
    else if reorient thy prems lhs rhs then
wenzelm@16458
   487
      if reorient thy prems rhs lhs
wenzelm@15023
   488
      then mk_eq_True ss (thm, name)
wenzelm@15023
   489
      else
wenzelm@18208
   490
        (case mk_sym thm of
wenzelm@18208
   491
          NONE => []
wenzelm@18208
   492
        | SOME thm' =>
wenzelm@18208
   493
            let val (_, _, lhs', elhs', rhs', _) = decomp_simp thm'
wenzelm@18208
   494
            in rrule_eq_True (thm', name, lhs', elhs', rhs', ss, thm) end)
wenzelm@15023
   495
    else rrule_eq_True (thm, name, lhs, elhs, rhs, ss, thm)
berghofe@10413
   496
  end;
berghofe@10413
   497
nipkow@15199
   498
fun extract_rews (Simpset (_, {mk_rews = {mk, ...}, ...}), thms) =
wenzelm@19482
   499
  maps (fn thm => map (rpair (Thm.name_of_thm thm)) (mk thm)) thms;
berghofe@10413
   500
wenzelm@15023
   501
fun extract_safe_rrules (ss, thm) =
wenzelm@19482
   502
  maps (orient_rrule ss) (extract_rews (ss, [thm]));
berghofe@10413
   503
berghofe@10413
   504
wenzelm@20028
   505
(* add/del rules explicitly *)
berghofe@10413
   506
wenzelm@20028
   507
fun comb_simps comb mk_rrule (ss, thms) =
wenzelm@20028
   508
  let
wenzelm@20028
   509
    val rews = extract_rews (ss, thms);
wenzelm@20028
   510
  in fold (fold comb o mk_rrule) rews ss end;
berghofe@10413
   511
wenzelm@20028
   512
fun ss addsimps thms =
wenzelm@20028
   513
  comb_simps insert_rrule (mk_rrule ss) (ss, thms);
berghofe@10413
   514
wenzelm@15023
   515
fun ss delsimps thms =
wenzelm@20028
   516
  comb_simps del_rrule (map mk_rrule2 o mk_rrule ss) (ss, thms);
wenzelm@15023
   517
wenzelm@15023
   518
wenzelm@15023
   519
(* congs *)
berghofe@10413
   520
skalberg@15531
   521
fun cong_name (Const (a, _)) = SOME a
skalberg@15531
   522
  | cong_name (Free (a, _)) = SOME ("Free: " ^ a)
skalberg@15531
   523
  | cong_name _ = NONE;
ballarin@13835
   524
wenzelm@15023
   525
local
wenzelm@15023
   526
wenzelm@15023
   527
fun is_full_cong_prems [] [] = true
wenzelm@15023
   528
  | is_full_cong_prems [] _ = false
wenzelm@15023
   529
  | is_full_cong_prems (p :: prems) varpairs =
wenzelm@15023
   530
      (case Logic.strip_assums_concl p of
wenzelm@15023
   531
        Const ("==", _) $ lhs $ rhs =>
wenzelm@15023
   532
          let val (x, xs) = strip_comb lhs and (y, ys) = strip_comb rhs in
wenzelm@15023
   533
            is_Var x andalso forall is_Bound xs andalso
wenzelm@15023
   534
            null (findrep xs) andalso xs = ys andalso
wenzelm@15023
   535
            (x, y) mem varpairs andalso
wenzelm@19303
   536
            is_full_cong_prems prems (remove (op =) (x, y) varpairs)
wenzelm@15023
   537
          end
wenzelm@15023
   538
      | _ => false);
wenzelm@15023
   539
wenzelm@15023
   540
fun is_full_cong thm =
berghofe@10413
   541
  let
wenzelm@15023
   542
    val prems = prems_of thm and concl = concl_of thm;
wenzelm@15023
   543
    val (lhs, rhs) = Logic.dest_equals concl;
wenzelm@15023
   544
    val (f, xs) = strip_comb lhs and (g, ys) = strip_comb rhs;
berghofe@10413
   545
  in
wenzelm@15023
   546
    f = g andalso null (findrep (xs @ ys)) andalso length xs = length ys andalso
wenzelm@15023
   547
    is_full_cong_prems prems (xs ~~ ys)
berghofe@10413
   548
  end;
berghofe@10413
   549
wenzelm@15023
   550
fun add_cong (ss, thm) = ss |>
wenzelm@15023
   551
  map_simpset2 (fn (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers) =>
wenzelm@15023
   552
    let
wenzelm@15023
   553
      val (lhs, _) = Drule.dest_equals (Drule.strip_imp_concl (Thm.cprop_of thm))
wenzelm@15023
   554
        handle TERM _ => raise SIMPLIFIER ("Congruence not a meta-equality", thm);
wenzelm@18929
   555
    (*val lhs = Envir.eta_contract lhs;*)
wenzelm@20057
   556
      val a = the (cong_name (head_of (term_of lhs))) handle Option.Option =>
wenzelm@15023
   557
        raise SIMPLIFIER ("Congruence must start with a constant or free variable", thm);
wenzelm@15023
   558
      val (alist, weak) = congs;
wenzelm@15023
   559
      val alist2 = overwrite_warn (alist, (a, {lhs = lhs, thm = thm}))
wenzelm@15023
   560
        ("Overwriting congruence rule for " ^ quote a);
wenzelm@15023
   561
      val weak2 = if is_full_cong thm then weak else a :: weak;
wenzelm@15023
   562
    in ((alist2, weak2), procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers) end);
berghofe@10413
   563
wenzelm@15023
   564
fun del_cong (ss, thm) = ss |>
wenzelm@15023
   565
  map_simpset2 (fn (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers) =>
wenzelm@15023
   566
    let
wenzelm@15023
   567
      val (lhs, _) = Logic.dest_equals (Thm.concl_of thm) handle TERM _ =>
wenzelm@15023
   568
        raise SIMPLIFIER ("Congruence not a meta-equality", thm);
wenzelm@18929
   569
    (*val lhs = Envir.eta_contract lhs;*)
wenzelm@20057
   570
      val a = the (cong_name (head_of lhs)) handle Option.Option =>
wenzelm@15023
   571
        raise SIMPLIFIER ("Congruence must start with a constant", thm);
wenzelm@15023
   572
      val (alist, _) = congs;
skalberg@15570
   573
      val alist2 = List.filter (fn (x, _) => x <> a) alist;
wenzelm@19482
   574
      val weak2 = alist2 |> map_filter (fn (a, {thm, ...}: cong) =>
skalberg@15531
   575
        if is_full_cong thm then NONE else SOME a);
wenzelm@15023
   576
    in ((alist2, weak2), procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers) end);
berghofe@10413
   577
wenzelm@15023
   578
fun mk_cong (Simpset (_, {mk_rews = {mk_cong = f, ...}, ...})) = f;
wenzelm@15023
   579
wenzelm@15023
   580
in
wenzelm@15023
   581
skalberg@15570
   582
val (op addeqcongs) = Library.foldl add_cong;
skalberg@15570
   583
val (op deleqcongs) = Library.foldl del_cong;
wenzelm@15023
   584
wenzelm@15023
   585
fun ss addcongs congs = ss addeqcongs map (mk_cong ss) congs;
wenzelm@15023
   586
fun ss delcongs congs = ss deleqcongs map (mk_cong ss) congs;
wenzelm@15023
   587
wenzelm@15023
   588
end;
berghofe@10413
   589
berghofe@10413
   590
wenzelm@15023
   591
(* simprocs *)
wenzelm@15023
   592
wenzelm@15023
   593
local
berghofe@10413
   594
wenzelm@16985
   595
fun add_proc (proc as Proc {name, lhs, ...}) ss =
wenzelm@16985
   596
 (trace_cterm false ("Adding simplification procedure " ^ quote name ^ " for") ss lhs;
wenzelm@15023
   597
  map_simpset2 (fn (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers) =>
wenzelm@16807
   598
    (congs, Net.insert_term eq_proc (term_of lhs, proc) procs,
wenzelm@15023
   599
      mk_rews, termless, subgoal_tac, loop_tacs, solvers)) ss
wenzelm@15023
   600
  handle Net.INSERT =>
wenzelm@15023
   601
    (warning ("Ignoring duplicate simplification procedure " ^ quote name); ss));
berghofe@10413
   602
wenzelm@16985
   603
fun del_proc (proc as Proc {name, lhs, ...}) ss =
wenzelm@15023
   604
  map_simpset2 (fn (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers) =>
wenzelm@16807
   605
    (congs, Net.delete_term eq_proc (term_of lhs, proc) procs,
wenzelm@15023
   606
      mk_rews, termless, subgoal_tac, loop_tacs, solvers)) ss
wenzelm@15023
   607
  handle Net.DELETE =>
wenzelm@15023
   608
    (warning ("Simplification procedure " ^ quote name ^ " not in simpset"); ss);
berghofe@10413
   609
wenzelm@15023
   610
in
berghofe@10413
   611
wenzelm@16985
   612
fun ss addsimprocs ps = fold (fn Simproc procs => fold add_proc procs) ps ss;
wenzelm@16985
   613
fun ss delsimprocs ps = fold (fn Simproc procs => fold del_proc procs) ps ss;
berghofe@10413
   614
wenzelm@15023
   615
end;
berghofe@10413
   616
berghofe@10413
   617
berghofe@10413
   618
(* mk_rews *)
berghofe@10413
   619
wenzelm@15023
   620
local
wenzelm@15023
   621
wenzelm@18208
   622
fun map_mk_rews f = map_simpset2 (fn (congs, procs, {mk, mk_cong, mk_sym, mk_eq_True, reorient},
wenzelm@15023
   623
      termless, subgoal_tac, loop_tacs, solvers) =>
wenzelm@18208
   624
  let
wenzelm@18208
   625
    val (mk', mk_cong', mk_sym', mk_eq_True', reorient') =
wenzelm@18208
   626
      f (mk, mk_cong, mk_sym, mk_eq_True, reorient);
wenzelm@18208
   627
    val mk_rews' = {mk = mk', mk_cong = mk_cong', mk_sym = mk_sym', mk_eq_True = mk_eq_True',
wenzelm@18208
   628
      reorient = reorient'};
wenzelm@18208
   629
  in (congs, procs, mk_rews', termless, subgoal_tac, loop_tacs, solvers) end);
wenzelm@15023
   630
wenzelm@15023
   631
in
berghofe@10413
   632
wenzelm@18208
   633
fun ss setmksimps mk = ss |> map_mk_rews (fn (_, mk_cong, mk_sym, mk_eq_True, reorient) =>
wenzelm@18208
   634
  (mk, mk_cong, mk_sym, mk_eq_True, reorient));
wenzelm@15023
   635
wenzelm@18208
   636
fun ss setmkcong mk_cong = ss |> map_mk_rews (fn (mk, _, mk_sym, mk_eq_True, reorient) =>
wenzelm@18208
   637
  (mk, mk_cong, mk_sym, mk_eq_True, reorient));
berghofe@10413
   638
wenzelm@18208
   639
fun ss setmksym mk_sym = ss |> map_mk_rews (fn (mk, mk_cong, _, mk_eq_True, reorient) =>
wenzelm@18208
   640
  (mk, mk_cong, mk_sym, mk_eq_True, reorient));
berghofe@10413
   641
wenzelm@18208
   642
fun ss setmkeqTrue mk_eq_True = ss |> map_mk_rews (fn (mk, mk_cong, mk_sym, _, reorient) =>
wenzelm@18208
   643
  (mk, mk_cong, mk_sym, mk_eq_True, reorient));
wenzelm@18208
   644
wenzelm@18208
   645
fun set_reorient reorient = map_mk_rews (fn (mk, mk_cong, mk_sym, mk_eq_True, _) =>
wenzelm@18208
   646
  (mk, mk_cong, mk_sym, mk_eq_True, reorient));
wenzelm@15023
   647
wenzelm@15023
   648
end;
wenzelm@15023
   649
skalberg@14242
   650
berghofe@10413
   651
(* termless *)
berghofe@10413
   652
wenzelm@15023
   653
fun ss settermless termless = ss |>
wenzelm@15023
   654
  map_simpset2 (fn (congs, procs, mk_rews, _, subgoal_tac, loop_tacs, solvers) =>
wenzelm@15023
   655
   (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers));
skalberg@15006
   656
skalberg@15006
   657
wenzelm@15023
   658
(* tactics *)
skalberg@15006
   659
wenzelm@15023
   660
fun ss setsubgoaler subgoal_tac = ss |>
wenzelm@15023
   661
  map_simpset2 (fn (congs, procs, mk_rews, termless, _, loop_tacs, solvers) =>
wenzelm@15023
   662
   (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers));
skalberg@15006
   663
wenzelm@17882
   664
fun ss setloop' tac = ss |>
wenzelm@15023
   665
  map_simpset2 (fn (congs, procs, mk_rews, termless, subgoal_tac, _, solvers) =>
wenzelm@15023
   666
   (congs, procs, mk_rews, termless, subgoal_tac, [("", tac)], solvers));
skalberg@15006
   667
wenzelm@17882
   668
fun ss setloop tac = ss setloop' (K tac);
wenzelm@17882
   669
wenzelm@17882
   670
fun ss addloop' (name, tac) = ss |>
wenzelm@15023
   671
  map_simpset2 (fn (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers) =>
wenzelm@15023
   672
    (congs, procs, mk_rews, termless, subgoal_tac,
wenzelm@15023
   673
      overwrite_warn (loop_tacs, (name, tac)) ("Overwriting looper " ^ quote name),
wenzelm@15023
   674
      solvers));
skalberg@15006
   675
wenzelm@17882
   676
fun ss addloop (name, tac) = ss addloop' (name, K tac);
wenzelm@17882
   677
wenzelm@15023
   678
fun ss delloop name = ss |>
wenzelm@15023
   679
  map_simpset2 (fn (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, solvers) =>
wenzelm@17756
   680
    let val loop_tacs' = filter_out (equal name o fst) loop_tacs in
wenzelm@15034
   681
      if length loop_tacs <> length loop_tacs' then ()
wenzelm@15034
   682
      else warning ("No such looper in simpset: " ^ quote name);
wenzelm@15034
   683
      (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs', solvers)
wenzelm@15023
   684
    end);
skalberg@15006
   685
wenzelm@15023
   686
fun ss setSSolver solver = ss |> map_simpset2 (fn (congs, procs, mk_rews, termless,
wenzelm@15023
   687
  subgoal_tac, loop_tacs, (unsafe_solvers, _)) =>
wenzelm@15023
   688
    (congs, procs, mk_rews, termless, subgoal_tac, loop_tacs, (unsafe_solvers, [solver])));
skalberg@15006
   689
wenzelm@15023
   690
fun ss addSSolver solver = ss |> map_simpset2 (fn (congs, procs, mk_rews, termless,
wenzelm@15023
   691
  subgoal_tac, loop_tacs, (unsafe_solvers, solvers)) => (congs, procs, mk_rews, termless,
wenzelm@15023
   692
    subgoal_tac, loop_tacs, (unsafe_solvers, merge_solvers solvers [solver])));
skalberg@15006
   693
wenzelm@15023
   694
fun ss setSolver solver = ss |> map_simpset2 (fn (congs, procs, mk_rews, termless,
wenzelm@15023
   695
  subgoal_tac, loop_tacs, (_, solvers)) => (congs, procs, mk_rews, termless,
wenzelm@15023
   696
    subgoal_tac, loop_tacs, ([solver], solvers)));
skalberg@15006
   697
wenzelm@15023
   698
fun ss addSolver solver = ss |> map_simpset2 (fn (congs, procs, mk_rews, termless,
wenzelm@15023
   699
  subgoal_tac, loop_tacs, (unsafe_solvers, solvers)) => (congs, procs, mk_rews, termless,
wenzelm@15023
   700
    subgoal_tac, loop_tacs, (merge_solvers unsafe_solvers [solver], solvers)));
skalberg@15006
   701
wenzelm@15023
   702
fun set_solvers solvers = map_simpset2 (fn (congs, procs, mk_rews, termless,
wenzelm@15023
   703
  subgoal_tac, loop_tacs, _) => (congs, procs, mk_rews, termless,
wenzelm@15023
   704
  subgoal_tac, loop_tacs, (solvers, solvers)));
skalberg@15006
   705
skalberg@15006
   706
wenzelm@18208
   707
(* empty *)
wenzelm@18208
   708
wenzelm@18208
   709
fun init_ss mk_rews termless subgoal_tac solvers =
wenzelm@18208
   710
  make_simpset ((Net.empty, [], (0, []), NONE),
wenzelm@18208
   711
    (([], []), Net.empty, mk_rews, termless, subgoal_tac, [], solvers));
wenzelm@18208
   712
wenzelm@18208
   713
fun clear_ss (ss as Simpset (_, {mk_rews, termless, subgoal_tac, solvers, ...})) =
wenzelm@18208
   714
  init_ss mk_rews termless subgoal_tac solvers
wenzelm@18208
   715
  |> inherit_context ss;
wenzelm@18208
   716
wenzelm@18208
   717
val basic_mk_rews: mk_rews =
wenzelm@18208
   718
 {mk = fn th => if can Logic.dest_equals (Thm.concl_of th) then [th] else [],
wenzelm@18208
   719
  mk_cong = I,
wenzelm@18208
   720
  mk_sym = SOME o Drule.symmetric_fun,
wenzelm@18208
   721
  mk_eq_True = K NONE,
wenzelm@18208
   722
  reorient = default_reorient};
wenzelm@18208
   723
wenzelm@18208
   724
val empty_ss = init_ss basic_mk_rews Term.termless (K (K no_tac)) ([], []);
wenzelm@18208
   725
wenzelm@18208
   726
wenzelm@18208
   727
(* merge *)  (*NOTE: ignores some fields of 2nd simpset*)
wenzelm@18208
   728
wenzelm@18208
   729
fun merge_ss (ss1, ss2) =
wenzelm@18208
   730
  let
wenzelm@18208
   731
    val Simpset ({rules = rules1, prems = prems1, bounds = bounds1, context = _},
wenzelm@18208
   732
     {congs = (congs1, weak1), procs = procs1, mk_rews, termless, subgoal_tac,
wenzelm@18208
   733
      loop_tacs = loop_tacs1, solvers = (unsafe_solvers1, solvers1)}) = ss1;
wenzelm@18208
   734
    val Simpset ({rules = rules2, prems = prems2, bounds = bounds2, context = _},
wenzelm@18208
   735
     {congs = (congs2, weak2), procs = procs2, mk_rews = _, termless = _, subgoal_tac = _,
wenzelm@18208
   736
      loop_tacs = loop_tacs2, solvers = (unsafe_solvers2, solvers2)}) = ss2;
wenzelm@18208
   737
wenzelm@18208
   738
    val rules' = Net.merge eq_rrule (rules1, rules2);
wenzelm@18208
   739
    val prems' = gen_merge_lists Drule.eq_thm_prop prems1 prems2;
wenzelm@18208
   740
    val bounds' = if #1 bounds1 < #1 bounds2 then bounds2 else bounds1;
wenzelm@18208
   741
    val congs' = gen_merge_lists (eq_cong o pairself #2) congs1 congs2;
wenzelm@18208
   742
    val weak' = merge_lists weak1 weak2;
wenzelm@18208
   743
    val procs' = Net.merge eq_proc (procs1, procs2);
wenzelm@18208
   744
    val loop_tacs' = merge_alists loop_tacs1 loop_tacs2;
wenzelm@18208
   745
    val unsafe_solvers' = merge_solvers unsafe_solvers1 unsafe_solvers2;
wenzelm@18208
   746
    val solvers' = merge_solvers solvers1 solvers2;
wenzelm@18208
   747
  in
wenzelm@18208
   748
    make_simpset ((rules', prems', bounds', NONE), ((congs', weak'), procs',
wenzelm@18208
   749
      mk_rews, termless, subgoal_tac, loop_tacs', (unsafe_solvers', solvers')))
wenzelm@18208
   750
  end;
wenzelm@18208
   751
wenzelm@18208
   752
skalberg@15006
   753
berghofe@10413
   754
(** rewriting **)
berghofe@10413
   755
berghofe@10413
   756
(*
berghofe@10413
   757
  Uses conversions, see:
berghofe@10413
   758
    L C Paulson, A higher-order implementation of rewriting,
berghofe@10413
   759
    Science of Computer Programming 3 (1983), pages 119-149.
berghofe@10413
   760
*)
berghofe@10413
   761
wenzelm@15023
   762
val dest_eq = Drule.dest_equals o Thm.cprop_of;
wenzelm@15023
   763
val lhs_of = #1 o dest_eq;
wenzelm@15023
   764
val rhs_of = #2 o dest_eq;
berghofe@10413
   765
wenzelm@16985
   766
fun check_conv msg ss thm thm' =
berghofe@10413
   767
  let
berghofe@10413
   768
    val thm'' = transitive thm (transitive
skalberg@15001
   769
      (symmetric (Drule.beta_eta_conversion (lhs_of thm'))) thm')
wenzelm@16985
   770
  in if msg then trace_thm "SUCCEEDED" ss thm' else (); SOME thm'' end
berghofe@10413
   771
  handle THM _ =>
wenzelm@16458
   772
    let val {thy, prop = _ $ _ $ prop0, ...} = Thm.rep_thm thm in
wenzelm@16985
   773
      trace_thm "Proved wrong thm (Check subgoaler?)" ss thm';
wenzelm@16985
   774
      trace_term false "Should have proved:" ss thy prop0;
skalberg@15531
   775
      NONE
berghofe@10413
   776
    end;
berghofe@10413
   777
berghofe@10413
   778
berghofe@10413
   779
(* mk_procrule *)
berghofe@10413
   780
wenzelm@16985
   781
fun mk_procrule ss thm =
wenzelm@15023
   782
  let val (_, prems, lhs, elhs, rhs, _) = decomp_simp thm in
wenzelm@15023
   783
    if rewrite_rule_extra_vars prems lhs rhs
wenzelm@16985
   784
    then (warn_thm "Extra vars on rhs:" ss thm; [])
wenzelm@15023
   785
    else [mk_rrule2 {thm = thm, name = "", lhs = lhs, elhs = elhs, perm = false}]
berghofe@10413
   786
  end;
berghofe@10413
   787
berghofe@10413
   788
wenzelm@15023
   789
(* rewritec: conversion to apply the meta simpset to a term *)
berghofe@10413
   790
wenzelm@15023
   791
(*Since the rewriting strategy is bottom-up, we avoid re-normalizing already
wenzelm@15023
   792
  normalized terms by carrying around the rhs of the rewrite rule just
wenzelm@15023
   793
  applied. This is called the `skeleton'. It is decomposed in parallel
wenzelm@15023
   794
  with the term. Once a Var is encountered, the corresponding term is
wenzelm@15023
   795
  already in normal form.
wenzelm@15023
   796
  skel0 is a dummy skeleton that is to enforce complete normalization.*)
wenzelm@15023
   797
berghofe@10413
   798
val skel0 = Bound 0;
berghofe@10413
   799
wenzelm@15023
   800
(*Use rhs as skeleton only if the lhs does not contain unnormalized bits.
wenzelm@15023
   801
  The latter may happen iff there are weak congruence rules for constants
wenzelm@15023
   802
  in the lhs.*)
berghofe@10413
   803
wenzelm@15023
   804
fun uncond_skel ((_, weak), (lhs, rhs)) =
wenzelm@15023
   805
  if null weak then rhs  (*optimization*)
wenzelm@15023
   806
  else if exists_Const (fn (c, _) => c mem weak) lhs then skel0
wenzelm@15023
   807
  else rhs;
wenzelm@15023
   808
wenzelm@15023
   809
(*Behaves like unconditional rule if rhs does not contain vars not in the lhs.
wenzelm@15023
   810
  Otherwise those vars may become instantiated with unnormalized terms
wenzelm@15023
   811
  while the premises are solved.*)
wenzelm@15023
   812
wenzelm@15023
   813
fun cond_skel (args as (congs, (lhs, rhs))) =
wenzelm@15023
   814
  if term_varnames rhs subset term_varnames lhs then uncond_skel args
berghofe@10413
   815
  else skel0;
berghofe@10413
   816
berghofe@10413
   817
(*
wenzelm@15023
   818
  Rewriting -- we try in order:
berghofe@10413
   819
    (1) beta reduction
berghofe@10413
   820
    (2) unconditional rewrite rules
berghofe@10413
   821
    (3) conditional rewrite rules
berghofe@10413
   822
    (4) simplification procedures
berghofe@10413
   823
berghofe@10413
   824
  IMPORTANT: rewrite rules must not introduce new Vars or TVars!
berghofe@10413
   825
*)
berghofe@10413
   826
wenzelm@16458
   827
fun rewritec (prover, thyt, maxt) ss t =
berghofe@10413
   828
  let
wenzelm@15023
   829
    val Simpset ({rules, ...}, {congs, procs, termless, ...}) = ss;
berghofe@10413
   830
    val eta_thm = Thm.eta_conversion t;
berghofe@10413
   831
    val eta_t' = rhs_of eta_thm;
berghofe@10413
   832
    val eta_t = term_of eta_t';
berghofe@13607
   833
    fun rew {thm, name, lhs, elhs, fo, perm} =
berghofe@10413
   834
      let
wenzelm@16458
   835
        val {thy, prop, maxidx, ...} = rep_thm thm;
berghofe@10413
   836
        val (rthm, elhs') = if maxt = ~1 then (thm, elhs)
berghofe@10413
   837
          else (Thm.incr_indexes (maxt+1) thm, Thm.cterm_incr_indexes (maxt+1) elhs);
berghofe@10413
   838
        val insts = if fo then Thm.cterm_first_order_match (elhs', eta_t')
berghofe@10413
   839
                          else Thm.cterm_match (elhs', eta_t');
berghofe@10413
   840
        val thm' = Thm.instantiate insts (Thm.rename_boundvars lhs eta_t rthm);
wenzelm@14643
   841
        val prop' = Thm.prop_of thm';
berghofe@10413
   842
        val unconditional = (Logic.count_prems (prop',0) = 0);
berghofe@10413
   843
        val (lhs', rhs') = Logic.dest_equals (Logic.strip_imp_concl prop')
berghofe@10413
   844
      in
nipkow@11295
   845
        if perm andalso not (termless (rhs', lhs'))
wenzelm@16985
   846
        then (trace_named_thm "Cannot apply permutative rewrite rule" ss (thm, name);
wenzelm@16985
   847
              trace_thm "Term does not become smaller:" ss thm'; NONE)
wenzelm@16985
   848
        else (trace_named_thm "Applying instance of rewrite rule" ss (thm, name);
berghofe@10413
   849
           if unconditional
berghofe@10413
   850
           then
wenzelm@16985
   851
             (trace_thm "Rewriting:" ss thm';
berghofe@10413
   852
              let val lr = Logic.dest_equals prop;
wenzelm@16985
   853
                  val SOME thm'' = check_conv false ss eta_thm thm'
skalberg@15531
   854
              in SOME (thm'', uncond_skel (congs, lr)) end)
berghofe@10413
   855
           else
wenzelm@16985
   856
             (trace_thm "Trying to rewrite:" ss thm';
nipkow@16042
   857
              if !simp_depth > !simp_depth_limit
nipkow@16042
   858
              then let val s = "simp_depth_limit exceeded - giving up"
nipkow@16042
   859
                   in trace false s; warning s; NONE end
nipkow@16042
   860
              else
nipkow@16042
   861
              case prover ss thm' of
wenzelm@16985
   862
                NONE => (trace_thm "FAILED" ss thm'; NONE)
skalberg@15531
   863
              | SOME thm2 =>
wenzelm@16985
   864
                  (case check_conv true ss eta_thm thm2 of
skalberg@15531
   865
                     NONE => NONE |
skalberg@15531
   866
                     SOME thm2' =>
berghofe@10413
   867
                       let val concl = Logic.strip_imp_concl prop
berghofe@10413
   868
                           val lr = Logic.dest_equals concl
nipkow@16042
   869
                       in SOME (thm2', cond_skel (congs, lr)) end)))
berghofe@10413
   870
      end
berghofe@10413
   871
skalberg@15531
   872
    fun rews [] = NONE
berghofe@10413
   873
      | rews (rrule :: rrules) =
skalberg@15531
   874
          let val opt = rew rrule handle Pattern.MATCH => NONE
skalberg@15531
   875
          in case opt of NONE => rews rrules | some => some end;
berghofe@10413
   876
berghofe@10413
   877
    fun sort_rrules rrs = let
wenzelm@14643
   878
      fun is_simple({thm, ...}:rrule) = case Thm.prop_of thm of
berghofe@10413
   879
                                      Const("==",_) $ _ $ _ => true
wenzelm@12603
   880
                                      | _                   => false
berghofe@10413
   881
      fun sort []        (re1,re2) = re1 @ re2
wenzelm@12603
   882
        | sort (rr::rrs) (re1,re2) = if is_simple rr
berghofe@10413
   883
                                     then sort rrs (rr::re1,re2)
berghofe@10413
   884
                                     else sort rrs (re1,rr::re2)
berghofe@10413
   885
    in sort rrs ([],[]) end
berghofe@10413
   886
skalberg@15531
   887
    fun proc_rews [] = NONE
wenzelm@15023
   888
      | proc_rews (Proc {name, proc, lhs, ...} :: ps) =
wenzelm@17203
   889
          if Pattern.matches thyt (Thm.term_of lhs, Thm.term_of t) then
wenzelm@16985
   890
            (debug_term false ("Trying procedure " ^ quote name ^ " on:") ss thyt eta_t;
wenzelm@13486
   891
             case transform_failure (curry SIMPROC_FAIL name)
wenzelm@16458
   892
                 (fn () => proc thyt ss eta_t) () of
skalberg@15531
   893
               NONE => (debug false "FAILED"; proc_rews ps)
skalberg@15531
   894
             | SOME raw_thm =>
wenzelm@16985
   895
                 (trace_thm ("Procedure " ^ quote name ^ " produced rewrite rule:") ss raw_thm;
wenzelm@16985
   896
                  (case rews (mk_procrule ss raw_thm) of
skalberg@15531
   897
                    NONE => (trace_cterm true ("IGNORED result of simproc " ^ quote name ^
wenzelm@16985
   898
                      " -- does not match") ss t; proc_rews ps)
berghofe@10413
   899
                  | some => some)))
berghofe@10413
   900
          else proc_rews ps;
berghofe@10413
   901
  in case eta_t of
skalberg@15531
   902
       Abs _ $ _ => SOME (transitive eta_thm
berghofe@12155
   903
         (beta_conversion false eta_t'), skel0)
berghofe@10413
   904
     | _ => (case rews (sort_rrules (Net.match_term rules eta_t)) of
skalberg@15531
   905
               NONE => proc_rews (Net.match_term procs eta_t)
berghofe@10413
   906
             | some => some)
berghofe@10413
   907
  end;
berghofe@10413
   908
berghofe@10413
   909
berghofe@10413
   910
(* conversion to apply a congruence rule to a term *)
berghofe@10413
   911
wenzelm@16985
   912
fun congc prover ss maxt {thm=cong,lhs=lhs} t =
wenzelm@16985
   913
  let val rthm = Thm.incr_indexes (maxt+1) cong;
berghofe@10413
   914
      val rlhs = fst (Drule.dest_equals (Drule.strip_imp_concl (cprop_of rthm)));
berghofe@10413
   915
      val insts = Thm.cterm_match (rlhs, t)
berghofe@10413
   916
      (* Pattern.match can raise Pattern.MATCH;
berghofe@10413
   917
         is handled when congc is called *)
berghofe@10413
   918
      val thm' = Thm.instantiate insts (Thm.rename_boundvars (term_of rlhs) (term_of t) rthm);
wenzelm@16985
   919
      val unit = trace_thm "Applying congruence rule:" ss thm';
wenzelm@16985
   920
      fun err (msg, thm) = (trace_thm msg ss thm; NONE)
berghofe@10413
   921
  in case prover thm' of
skalberg@15531
   922
       NONE => err ("Congruence proof failed.  Could not prove", thm')
wenzelm@16985
   923
     | SOME thm2 => (case check_conv true ss (Drule.beta_eta_conversion t) thm2 of
skalberg@15531
   924
          NONE => err ("Congruence proof failed.  Should not have proved", thm2)
skalberg@15531
   925
        | SOME thm2' =>
berghofe@12155
   926
            if op aconv (pairself term_of (dest_equals (cprop_of thm2')))
skalberg@15531
   927
            then NONE else SOME thm2')
berghofe@10413
   928
  end;
berghofe@10413
   929
berghofe@10413
   930
val (cA, (cB, cC)) =
berghofe@10413
   931
  apsnd dest_equals (dest_implies (hd (cprems_of Drule.imp_cong)));
berghofe@10413
   932
skalberg@15531
   933
fun transitive1 NONE NONE = NONE
skalberg@15531
   934
  | transitive1 (SOME thm1) NONE = SOME thm1
skalberg@15531
   935
  | transitive1 NONE (SOME thm2) = SOME thm2
skalberg@15531
   936
  | transitive1 (SOME thm1) (SOME thm2) = SOME (transitive thm1 thm2)
berghofe@10413
   937
skalberg@15531
   938
fun transitive2 thm = transitive1 (SOME thm);
skalberg@15531
   939
fun transitive3 thm = transitive1 thm o SOME;
berghofe@13607
   940
wenzelm@16458
   941
fun bottomc ((simprem, useprem, mutsimp), prover, thy, maxidx) =
berghofe@10413
   942
  let
wenzelm@15023
   943
    fun botc skel ss t =
skalberg@15531
   944
          if is_Var skel then NONE
berghofe@10413
   945
          else
wenzelm@15023
   946
          (case subc skel ss t of
skalberg@15531
   947
             some as SOME thm1 =>
wenzelm@16458
   948
               (case rewritec (prover, thy, maxidx) ss (rhs_of thm1) of
skalberg@15531
   949
                  SOME (thm2, skel2) =>
berghofe@13607
   950
                    transitive2 (transitive thm1 thm2)
wenzelm@15023
   951
                      (botc skel2 ss (rhs_of thm2))
skalberg@15531
   952
                | NONE => some)
skalberg@15531
   953
           | NONE =>
wenzelm@16458
   954
               (case rewritec (prover, thy, maxidx) ss t of
skalberg@15531
   955
                  SOME (thm2, skel2) => transitive2 thm2
wenzelm@15023
   956
                    (botc skel2 ss (rhs_of thm2))
skalberg@15531
   957
                | NONE => NONE))
berghofe@10413
   958
wenzelm@15023
   959
    and try_botc ss t =
wenzelm@15023
   960
          (case botc skel0 ss t of
skalberg@15531
   961
             SOME trec1 => trec1 | NONE => (reflexive t))
berghofe@10413
   962
wenzelm@15023
   963
    and subc skel (ss as Simpset ({bounds, ...}, {congs, ...})) t0 =
berghofe@10413
   964
       (case term_of t0 of
berghofe@10413
   965
           Abs (a, T, t) =>
wenzelm@15023
   966
             let
wenzelm@16985
   967
                 val b = Term.bound (#1 bounds);
wenzelm@16985
   968
                 val (v, t') = Thm.dest_abs (SOME b) t0;
wenzelm@16985
   969
                 val b' = #1 (Term.dest_Free (Thm.term_of v));
wenzelm@16985
   970
                 val _ = conditional (b <> b') (fn () =>
wenzelm@16985
   971
                   warning ("Simplifier: renamed bound variable " ^ quote b ^ " to " ^ quote b'));
wenzelm@17614
   972
                 val ss' = add_bound ((b', T), a) ss;
wenzelm@15023
   973
                 val skel' = case skel of Abs (_, _, sk) => sk | _ => skel0;
wenzelm@15023
   974
             in case botc skel' ss' t' of
skalberg@15531
   975
                  SOME thm => SOME (abstract_rule a v thm)
skalberg@15531
   976
                | NONE => NONE
berghofe@10413
   977
             end
berghofe@10413
   978
         | t $ _ => (case t of
wenzelm@15023
   979
             Const ("==>", _) $ _  => impc t0 ss
berghofe@10413
   980
           | Abs _ =>
berghofe@10413
   981
               let val thm = beta_conversion false t0
wenzelm@15023
   982
               in case subc skel0 ss (rhs_of thm) of
skalberg@15531
   983
                    NONE => SOME thm
skalberg@15531
   984
                  | SOME thm' => SOME (transitive thm thm')
berghofe@10413
   985
               end
berghofe@10413
   986
           | _  =>
berghofe@10413
   987
               let fun appc () =
berghofe@10413
   988
                     let
berghofe@10413
   989
                       val (tskel, uskel) = case skel of
berghofe@10413
   990
                           tskel $ uskel => (tskel, uskel)
berghofe@10413
   991
                         | _ => (skel0, skel0);
wenzelm@10767
   992
                       val (ct, cu) = Thm.dest_comb t0
berghofe@10413
   993
                     in
wenzelm@15023
   994
                     (case botc tskel ss ct of
skalberg@15531
   995
                        SOME thm1 =>
wenzelm@15023
   996
                          (case botc uskel ss cu of
skalberg@15531
   997
                             SOME thm2 => SOME (combination thm1 thm2)
skalberg@15531
   998
                           | NONE => SOME (combination thm1 (reflexive cu)))
skalberg@15531
   999
                      | NONE =>
wenzelm@15023
  1000
                          (case botc uskel ss cu of
skalberg@15531
  1001
                             SOME thm1 => SOME (combination (reflexive ct) thm1)
skalberg@15531
  1002
                           | NONE => NONE))
berghofe@10413
  1003
                     end
berghofe@10413
  1004
                   val (h, ts) = strip_comb t
ballarin@13835
  1005
               in case cong_name h of
skalberg@15531
  1006
                    SOME a =>
haftmann@17232
  1007
                      (case AList.lookup (op =) (fst congs) a of
skalberg@15531
  1008
                         NONE => appc ()
skalberg@15531
  1009
                       | SOME cong =>
wenzelm@15023
  1010
  (*post processing: some partial applications h t1 ... tj, j <= length ts,
wenzelm@15023
  1011
    may be a redex. Example: map (%x. x) = (%xs. xs) wrt map_cong*)
berghofe@10413
  1012
                          (let
wenzelm@16985
  1013
                             val thm = congc (prover ss) ss maxidx cong t0;
wenzelm@19502
  1014
                             val t = the_default t0 (Option.map rhs_of thm);
wenzelm@10767
  1015
                             val (cl, cr) = Thm.dest_comb t
berghofe@10413
  1016
                             val dVar = Var(("", 0), dummyT)
berghofe@10413
  1017
                             val skel =
berghofe@10413
  1018
                               list_comb (h, replicate (length ts) dVar)
wenzelm@15023
  1019
                           in case botc skel ss cl of
skalberg@15531
  1020
                                NONE => thm
skalberg@15531
  1021
                              | SOME thm' => transitive3 thm
berghofe@12155
  1022
                                  (combination thm' (reflexive cr))
wenzelm@20057
  1023
                           end handle Pattern.MATCH => appc ()))
berghofe@10413
  1024
                  | _ => appc ()
berghofe@10413
  1025
               end)
skalberg@15531
  1026
         | _ => NONE)
berghofe@10413
  1027
wenzelm@15023
  1028
    and impc ct ss =
wenzelm@15023
  1029
      if mutsimp then mut_impc0 [] ct [] [] ss else nonmut_impc ct ss
berghofe@10413
  1030
wenzelm@15023
  1031
    and rules_of_prem ss prem =
berghofe@13607
  1032
      if maxidx_of_term (term_of prem) <> ~1
berghofe@13607
  1033
      then (trace_cterm true
wenzelm@16985
  1034
        "Cannot add premise as rewrite rule because it contains (type) unknowns:" ss prem; ([], NONE))
berghofe@13607
  1035
      else
berghofe@13607
  1036
        let val asm = assume prem
skalberg@15531
  1037
        in (extract_safe_rrules (ss, asm), SOME asm) end
berghofe@10413
  1038
wenzelm@15023
  1039
    and add_rrules (rrss, asms) ss =
wenzelm@20028
  1040
      (fold o fold) insert_rrule rrss ss |> add_prems (map_filter I asms)
berghofe@10413
  1041
berghofe@13607
  1042
    and disch r (prem, eq) =
berghofe@13607
  1043
      let
berghofe@13607
  1044
        val (lhs, rhs) = dest_eq eq;
berghofe@13607
  1045
        val eq' = implies_elim (Thm.instantiate
berghofe@13607
  1046
          ([], [(cA, prem), (cB, lhs), (cC, rhs)]) Drule.imp_cong)
berghofe@13607
  1047
          (implies_intr prem eq)
berghofe@13607
  1048
      in if not r then eq' else
berghofe@10413
  1049
        let
berghofe@13607
  1050
          val (prem', concl) = dest_implies lhs;
berghofe@13607
  1051
          val (prem'', _) = dest_implies rhs
berghofe@13607
  1052
        in transitive (transitive
berghofe@13607
  1053
          (Thm.instantiate ([], [(cA, prem'), (cB, prem), (cC, concl)])
berghofe@13607
  1054
             Drule.swap_prems_eq) eq')
berghofe@13607
  1055
          (Thm.instantiate ([], [(cA, prem), (cB, prem''), (cC, concl)])
berghofe@13607
  1056
             Drule.swap_prems_eq)
berghofe@10413
  1057
        end
berghofe@10413
  1058
      end
berghofe@10413
  1059
berghofe@13607
  1060
    and rebuild [] _ _ _ _ eq = eq
wenzelm@15023
  1061
      | rebuild (prem :: prems) concl (rrs :: rrss) (asm :: asms) ss eq =
berghofe@13607
  1062
          let
wenzelm@15023
  1063
            val ss' = add_rrules (rev rrss, rev asms) ss;
berghofe@13607
  1064
            val concl' =
wenzelm@19502
  1065
              Drule.mk_implies (prem, the_default concl (Option.map rhs_of eq));
skalberg@15570
  1066
            val dprem = Option.map (curry (disch false) prem)
wenzelm@16458
  1067
          in case rewritec (prover, thy, maxidx) ss' concl' of
skalberg@15531
  1068
              NONE => rebuild prems concl' rrss asms ss (dprem eq)
skalberg@15570
  1069
            | SOME (eq', _) => transitive2 (Library.foldl (disch false o swap)
wenzelm@19502
  1070
                  (the (transitive3 (dprem eq) eq'), prems))
wenzelm@15023
  1071
                (mut_impc0 (rev prems) (rhs_of eq') (rev rrss) (rev asms) ss)
berghofe@13607
  1072
          end
wenzelm@15023
  1073
wenzelm@15023
  1074
    and mut_impc0 prems concl rrss asms ss =
berghofe@13607
  1075
      let
berghofe@13607
  1076
        val prems' = strip_imp_prems concl;
wenzelm@15023
  1077
        val (rrss', asms') = split_list (map (rules_of_prem ss) prems')
berghofe@13607
  1078
      in mut_impc (prems @ prems') (strip_imp_concl concl) (rrss @ rrss')
wenzelm@15023
  1079
        (asms @ asms') [] [] [] [] ss ~1 ~1
berghofe@13607
  1080
      end
wenzelm@15023
  1081
wenzelm@15023
  1082
    and mut_impc [] concl [] [] prems' rrss' asms' eqns ss changed k =
skalberg@15570
  1083
        transitive1 (Library.foldl (fn (eq2, (eq1, prem)) => transitive1 eq1
skalberg@15570
  1084
            (Option.map (curry (disch false) prem) eq2)) (NONE, eqns ~~ prems'))
berghofe@13607
  1085
          (if changed > 0 then
berghofe@13607
  1086
             mut_impc (rev prems') concl (rev rrss') (rev asms')
wenzelm@15023
  1087
               [] [] [] [] ss ~1 changed
wenzelm@15023
  1088
           else rebuild prems' concl rrss' asms' ss
wenzelm@15023
  1089
             (botc skel0 (add_rrules (rev rrss', rev asms') ss) concl))
berghofe@13607
  1090
berghofe@13607
  1091
      | mut_impc (prem :: prems) concl (rrs :: rrss) (asm :: asms)
wenzelm@15023
  1092
          prems' rrss' asms' eqns ss changed k =
skalberg@15531
  1093
        case (if k = 0 then NONE else botc skel0 (add_rrules
wenzelm@15023
  1094
          (rev rrss' @ rrss, rev asms' @ asms) ss) prem) of
skalberg@15531
  1095
            NONE => mut_impc prems concl rrss asms (prem :: prems')
skalberg@15531
  1096
              (rrs :: rrss') (asm :: asms') (NONE :: eqns) ss changed
berghofe@13607
  1097
              (if k = 0 then 0 else k - 1)
skalberg@15531
  1098
          | SOME eqn =>
berghofe@13607
  1099
            let
berghofe@13607
  1100
              val prem' = rhs_of eqn;
berghofe@13607
  1101
              val tprems = map term_of prems;
skalberg@15570
  1102
              val i = 1 + Library.foldl Int.max (~1, map (fn p =>
wenzelm@19618
  1103
                find_index (fn q => q aconv p) tprems) (#hyps (rep_thm eqn)));
wenzelm@15023
  1104
              val (rrs', asm') = rules_of_prem ss prem'
berghofe@13607
  1105
            in mut_impc prems concl rrss asms (prem' :: prems')
skalberg@15574
  1106
              (rrs' :: rrss') (asm' :: asms') (SOME (foldr (disch true)
wenzelm@18470
  1107
                (Drule.imp_cong_rule eqn (reflexive (Drule.list_implies
skalberg@15574
  1108
                  (Library.drop (i, prems), concl)))) (Library.take (i, prems))) :: eqns) ss (length prems') ~1
berghofe@13607
  1109
            end
berghofe@13607
  1110
wenzelm@15023
  1111
     (*legacy code - only for backwards compatibility*)
wenzelm@15023
  1112
     and nonmut_impc ct ss =
berghofe@13607
  1113
       let val (prem, conc) = dest_implies ct;
skalberg@15531
  1114
           val thm1 = if simprem then botc skel0 ss prem else NONE;
wenzelm@19502
  1115
           val prem1 = the_default prem (Option.map rhs_of thm1);
wenzelm@15023
  1116
           val ss1 = if not useprem then ss else add_rrules
wenzelm@15023
  1117
             (apsnd single (apfst single (rules_of_prem ss prem1))) ss
wenzelm@15023
  1118
       in (case botc skel0 ss1 conc of
skalberg@15531
  1119
           NONE => (case thm1 of
skalberg@15531
  1120
               NONE => NONE
wenzelm@18470
  1121
             | SOME thm1' => SOME (Drule.imp_cong_rule thm1' (reflexive conc)))
skalberg@15531
  1122
         | SOME thm2 =>
berghofe@13607
  1123
           let val thm2' = disch false (prem1, thm2)
berghofe@10413
  1124
           in (case thm1 of
skalberg@15531
  1125
               NONE => SOME thm2'
skalberg@15531
  1126
             | SOME thm1' =>
wenzelm@18470
  1127
                 SOME (transitive (Drule.imp_cong_rule thm1' (reflexive conc)) thm2'))
berghofe@10413
  1128
           end)
berghofe@10413
  1129
       end
berghofe@10413
  1130
wenzelm@15023
  1131
 in try_botc end;
berghofe@10413
  1132
berghofe@10413
  1133
wenzelm@15023
  1134
(* Meta-rewriting: rewrites t to u and returns the theorem t==u *)
berghofe@10413
  1135
berghofe@10413
  1136
(*
berghofe@10413
  1137
  Parameters:
berghofe@10413
  1138
    mode = (simplify A,
berghofe@10413
  1139
            use A in simplifying B,
berghofe@10413
  1140
            use prems of B (if B is again a meta-impl.) to simplify A)
berghofe@10413
  1141
           when simplifying A ==> B
berghofe@10413
  1142
    prover: how to solve premises in conditional rewrites and congruences
berghofe@10413
  1143
*)
berghofe@10413
  1144
wenzelm@17705
  1145
val debug_bounds = ref false;
wenzelm@17705
  1146
wenzelm@17705
  1147
fun check_bounds ss ct = conditional (! debug_bounds) (fn () =>
wenzelm@17614
  1148
  let
wenzelm@17614
  1149
    val Simpset ({bounds = (_, bounds), ...}, _) = ss;
wenzelm@17614
  1150
    val bs = fold_aterms (fn Free (x, _) =>
wenzelm@17614
  1151
        if Term.is_bound x andalso not (AList.defined eq_bound bounds x)
wenzelm@17614
  1152
        then insert (op =) x else I
wenzelm@17614
  1153
      | _ => I) (term_of ct) [];
wenzelm@17705
  1154
  in
wenzelm@17705
  1155
    if null bs then ()
wenzelm@17723
  1156
    else print_term true ("Simplifier: term contains loose bounds: " ^ commas_quote bs) ss
wenzelm@17705
  1157
      (Thm.theory_of_cterm ct) (Thm.term_of ct)
wenzelm@17705
  1158
  end);
wenzelm@17614
  1159
wenzelm@19052
  1160
fun rewrite_cterm mode prover raw_ss raw_ct =
wenzelm@17882
  1161
  let
wenzelm@19052
  1162
    val ct = Thm.adjust_maxidx raw_ct;
wenzelm@17882
  1163
    val {thy, t, maxidx, ...} = Thm.rep_cterm ct;
wenzelm@17882
  1164
    val ss = fallback_context thy raw_ss;
wenzelm@17882
  1165
    val _ = inc simp_depth;
wenzelm@17882
  1166
    val _ = conditional (!simp_depth mod 20 = 0) (fn () =>
wenzelm@17882
  1167
      warning ("Simplification depth " ^ string_of_int (! simp_depth)));
wenzelm@17882
  1168
    val _ = trace_cterm false "SIMPLIFIER INVOKED ON THE FOLLOWING TERM:" ss ct;
wenzelm@17882
  1169
    val _ = check_bounds ss ct;
wenzelm@17882
  1170
    val res = bottomc (mode, Option.map Drule.flexflex_unique oo prover, thy, maxidx) ss ct
wenzelm@17882
  1171
  in dec simp_depth; res end
wenzelm@20057
  1172
  handle exn => (dec simp_depth; raise exn);  (* FIXME avoid handling of generic exceptions *)
berghofe@10413
  1173
wenzelm@11760
  1174
(*Rewrite a cterm*)
wenzelm@17897
  1175
fun rewrite_aux _ _ [] ct = Thm.reflexive ct
wenzelm@17897
  1176
  | rewrite_aux prover full thms ct =
wenzelm@17897
  1177
      rewrite_cterm (full, false, false) prover
wenzelm@17897
  1178
      (theory_context (Thm.theory_of_cterm ct) empty_ss addsimps thms) ct;
wenzelm@11672
  1179
berghofe@10413
  1180
(*Rewrite a theorem*)
wenzelm@17897
  1181
fun simplify_aux _ _ [] th = th
wenzelm@17897
  1182
  | simplify_aux prover full thms th =
wenzelm@17897
  1183
      Drule.fconv_rule (rewrite_cterm (full, false, false) prover
wenzelm@17897
  1184
        (theory_context (Thm.theory_of_thm th) empty_ss addsimps thms)) th;
berghofe@10413
  1185
wenzelm@15023
  1186
(*simple term rewriting -- no proof*)
wenzelm@16458
  1187
fun rewrite_term thy rules procs =
wenzelm@17203
  1188
  Pattern.rewrite_term thy (map decomp_simp' rules) procs;
wenzelm@15023
  1189
wenzelm@15023
  1190
fun rewrite_thm mode prover ss = Drule.fconv_rule (rewrite_cterm mode prover ss);
berghofe@10413
  1191
berghofe@10413
  1192
(*Rewrite the subgoals of a proof state (represented by a theorem) *)
wenzelm@19142
  1193
fun rewrite_goals_rule_aux prover thms th =
wenzelm@19142
  1194
  Drule.fconv_rule (Drule.goals_conv (K true) (rewrite_cterm (true, true, true) prover
wenzelm@19142
  1195
    (theory_context (Thm.theory_of_thm th) empty_ss addsimps thms))) th;
berghofe@10413
  1196
wenzelm@15023
  1197
(*Rewrite the subgoal of a proof state (represented by a theorem)*)
skalberg@15011
  1198
fun rewrite_goal_rule mode prover ss i thm =
berghofe@10413
  1199
  if 0 < i  andalso  i <= nprems_of thm
skalberg@15011
  1200
  then Drule.fconv_rule (Drule.goals_conv (fn j => j=i) (rewrite_cterm mode prover ss)) thm
berghofe@10413
  1201
  else raise THM("rewrite_goal_rule",i,[thm]);
berghofe@10413
  1202
berghofe@10413
  1203
end;
berghofe@10413
  1204
wenzelm@11672
  1205
structure BasicMetaSimplifier: BASIC_META_SIMPLIFIER = MetaSimplifier;
wenzelm@11672
  1206
open BasicMetaSimplifier;