boot-strap-pass-2-a.lisp

; ACL2 Version 8.4 -- A Computational Logic for Applicative Common Lisp
; Copyright (C) 2022, Regents of the University of Texas

; This version of ACL2 is a descendent of ACL2 Version 1.9, Copyright
; (C) 1997 Computational Logic, Inc.  See the documentation topic NOTE-2-0.

; This program is free software; you can redistribute it and/or modify
; it under the terms of the LICENSE file distributed with ACL2.

; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; LICENSE for more details.

; Written by:  Matt Kaufmann               and J Strother Moore
; email:       Kaufmann@cs.utexas.edu      and Moore@cs.utexas.edu
; Department of Computer Science
; University of Texas at Austin
; Austin, TX 78712 U.S.A.

(in-package "ACL2")

; This file is the first of a pair of files, boot-strap-pass-2-a.lisp and
; boot-strap-pass-2-b.lisp.  They are compiled and loaded; but they are only
; processed during the second pass of the boot-strap process, not the first.

; We introduce proper defattach events, i.e., without :skip-checks t.  Here are
; some guiding principles for making system functions available for attachment
; by users.

; - The initial attachment is named by adding the suffix -builtin.  For
;   example, worse-than is a constrained function initially attached to
;   worse-than-builtin.

; - Use the weakest logical specs we can (even if T), without getting
;   distracted by names.  For example, we do not specify a relationship between
;   worse-than-or-equal and worse-than.

; - Only make functions attachable if they are used in our sources somewhere
;   outside their definitions.  So for example, we do not introduce
;   worse-than-list as a constrained function, since its only use is in the
;   mutual-recursion event that defines worse-than.

; We conclude by defining some theories, near the end so that they pick up much
; of the rest of this file.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Miscellaneous verify-termination and guard verification
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; cons-term and symbol-class -- at one point during development, used in
; fncall-term, but anyhow, generally useful to have in logic mode

(verify-termination-boot-strap quote-listp) ; and guards
(verify-termination-boot-strap cons-term1) ; and guards
(verify-termination-boot-strap cons-term) ; and guards
(verify-termination-boot-strap symbol-class) ; and guards

; packn1, packn, and pack-to-string

(verify-termination-boot-strap packn1) ; and guards

(encapsulate ()

(local
 (defthm character-listp-explode-nonnegative-integer
   (implies (character-listp z)
            (character-listp (explode-nonnegative-integer x y z)))
   :rule-classes ((:forward-chaining :trigger-terms
                                     ((explode-nonnegative-integer x y z))))))

(local
 (defthm character-listp-explode-atom
   (character-listp (explode-atom x y))
   :rule-classes ((:forward-chaining :trigger-terms
                                     ((explode-atom x y))))))

(verify-termination-boot-strap packn-pos) ; and guards
(verify-termination-boot-strap find-first-non-cl-symbol) ; and guards
(verify-termination-boot-strap packn) ; and guards
(verify-termination-boot-strap pack-to-string) ; and guards
)

(verify-termination-boot-strap read-file-into-string1) ; and guards

; miscellaneous

(verify-termination-boot-strap guard-theorem-simplify-msg) ; and guards
(verify-termination-boot-strap guard-or-termination-theorem-msg) ; and guards
(verify-termination-boot-strap alist-keys-subsetp) ; and guards
(verify-termination-boot-strap keyword-listp) ; and guards
(verify-termination-boot-strap pairlis-x1) ; and guards
(verify-termination-boot-strap pairlis-x2) ; and guards
(verify-termination-boot-strap first-keyword) ; and guards
(verify-termination-boot-strap symbol-name-lst) ; and guards
; for case-match expansions:
(verify-termination-boot-strap symbol-name-equal) ; and guards
(verify-termination-boot-strap fix-pkg) ; and guards
(verify-termination-boot-strap unmake-true-list-cons-nest) ; and guards
(verify-termination-boot-strap dumb-negate-lit) ; and guards
(verify-termination-boot-strap flatten-ands-in-lit) ; and guards
(verify-termination-boot-strap union-equal-to-end) ; and guards
(verify-termination-boot-strap flatten-ands-in-lit!) ; and guards

(verify-guards warranted-fns-of-world)

; Convert defproxy events to :logic mode.
(defstub initialize-event-user (* * state) => state)
(defstub finalize-event-user (* * state) => state)
(defstub acl2x-expansion-alist (* state) => *)

#+acl2-loop-only
(partial-encapsulate
  (((canonical-pathname * * state) => *))

; Supporters = nil since each missing axiom equates a call of
; canonical-pathname on explicit arguments with its result.

  nil
  (local (defun canonical-pathname (x dir-p state)
           (declare (xargs :mode :logic))
           (declare (ignore dir-p state))
           (if (stringp x) x nil)))
  (defthm canonical-pathname-is-idempotent
    (equal (canonical-pathname (canonical-pathname x dir-p state) dir-p state)
           (canonical-pathname x dir-p state)))
  (defthm canonical-pathname-type
    (or (equal (canonical-pathname x dir-p state) nil)
        (stringp (canonical-pathname x dir-p state)))
    :rule-classes :type-prescription))

#+acl2-loop-only
(partial-encapsulate
  (((magic-ev-fncall * * state * *) => (mv * *)))

; Supporters = nil since each missing axiom equates a call of
; magic-ev-fncall on explicit arguments with its result.

  nil
  (logic)
  (local (defun magic-ev-fncall (fn args state hard-error-returns-nilp aok)
           (declare (xargs :mode :logic)
                    (ignore fn args state hard-error-returns-nilp aok))
           (mv nil nil))))

#+acl2-loop-only
(partial-encapsulate
  (((mfc-ap-fn * * state *) => *)
   ((mfc-relieve-hyp-fn * * * * * * state *) => *)
   ((mfc-relieve-hyp-ttree * * * * * * state *) => (mv * *))
   ((mfc-rw+-fn * * * * * state *) => *)
   ((mfc-rw+-ttree * * * * * state *) => (mv * *))
   ((mfc-rw-fn * * * * state *) => *)
   ((mfc-rw-ttree * * * * state *) => (mv * *))
   ((mfc-ts-fn * * state *) => *)
   ((mfc-ts-ttree * * state *) => (mv * *)))

; Supporters = nil since each missing axiom equates a call of one of the
; signature functions (above) on explicit arguments with its result.

  nil
  (logic)
  (set-ignore-ok t)
  (set-irrelevant-formals-ok t)
  (local (defun mfc-ts-fn (term mfc state forcep)
           t))
  (local (defun mfc-ts-ttree (term mfc state forcep)
           (mv t t)))
  (local (defun mfc-rw-fn (term obj equiv-info mfc state forcep)
           t))
  (local (defun mfc-rw-ttree (term obj equiv-info mfc state forcep)
           (mv t t)))
  (local (defun mfc-rw+-fn (term alist obj equiv-info mfc state forcep)
           t))
  (local (defun mfc-rw+-ttree (term alist obj equiv-info mfc state forcep)
           (mv t t)))
  (local (defun mfc-relieve-hyp-fn (hyp alist rune target bkptr mfc state
                                        forcep)
           t))
  (local (defun mfc-relieve-hyp-ttree (hyp alist rune target bkptr mfc state
                                           forcep)
           (mv t t)))
  (local (defun mfc-ap-fn (term mfc state forcep)
           t)))

(verify-termination-boot-strap print-object$-fn) ; and guards
(verify-termination-boot-strap print-object$) ; and guards
(verify-termination-boot-strap print-object$-preserving-case) ; and guards

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Attachment: too-many-ifs-post-rewrite and too-many-ifs-pre-rewrite
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

#+acl2-loop-only
; The above readtime conditional avoids a CLISP warning, and lets the defproxy
; for print-clause-id-okp provide the raw Lisp definition.
(encapsulate
 ((too-many-ifs-post-rewrite (args val) t
                             :guard (and (pseudo-term-listp args)
                                         (pseudo-termp val))))
 (local (defun too-many-ifs-post-rewrite (args val)
          (list args val))))

; The following events are derived from the original version of community book
; books/system/too-many-ifs.lisp.  But here we provide a proof that does not
; depend on books.  Our approach was to take the proof in the above book,
; eliminate the unnecessary use of an arithmetic book, expand away all uses of
; macros and make-events, avoid use of (theory 'minimal-theory) since that
; theory didn't yet exist (where these events were originally placed), and
; apply some additional hand-editing in order (for example) to remove hints
; depending on the tools/flag community book.  We have left original events
; from the book as comments.

(encapsulate
 ()

 (logic)

;;; (include-book "tools/flag" :dir :system)

; In the original book, but not needed for its certification:
; (include-book "arithmetic/top-with-meta" :dir :system)

; Comments like the following show events from the original book.

;;; (make-flag pseudo-termp-flg
;;;            pseudo-termp
;;;            :flag-var flg
;;;            :flag-mapping ((pseudo-termp term)
;;;                           (pseudo-term-listp list))
;;;            :defthm-macro-name defthm-pseudo-termp
;;;            :local t)

 (local
  (defun-nx pseudo-termp-flg (flg x lst)
    (declare (xargs :verify-guards nil
                    :normalize nil
                    :measure (case flg (term (acl2-count x))
                               (otherwise (acl2-count lst)))))
    (case flg
      (term (if (consp x)
                (cond ((equal (car x) 'quote)
                       (and (consp (cdr x))
                            (equal (cddr x) nil)))
                      ((true-listp x)
                       (and (pseudo-termp-flg 'list nil (cdr x))
                            (cond ((symbolp (car x)) t)
                                  ((true-listp (car x))
                                   (and (equal (length (car x)) 3)
                                        (equal (caar x) 'lambda)
                                        (symbol-listp (cadar x))
                                        (pseudo-termp-flg 'term (caddar x) nil)
                                        (equal (length (cadar x))
                                               (length (cdr x)))))
                                  (t nil))))
                      (t nil))
              (symbolp x)))
      (otherwise (if (consp lst)
                     (and (pseudo-termp-flg 'term (car lst) nil)
                          (pseudo-termp-flg 'list nil (cdr lst)))
                   (equal lst nil))))))
 (local
  (defthm pseudo-termp-flg-equivalences
    (equal (pseudo-termp-flg flg x lst)
           (case flg (term (pseudo-termp x))
             (otherwise (pseudo-term-listp lst))))
    :hints
    (("goal" :induct (pseudo-termp-flg flg x lst)))))
 (local (in-theory (disable (:definition pseudo-termp-flg))))

; Added here (not present or needed in the certified book):
 (verify-termination-boot-strap max) ; and guards

 (verify-termination-boot-strap var-counts1)

;;; (make-flag var-counts1-flg
;;;            var-counts1
;;;            :flag-var flg
;;;            :flag-mapping ((var-counts1 term)
;;;                           (var-counts1-lst list))
;;;            :defthm-macro-name defthm-var-counts1
;;;            :local t)

 (local
  (defun-nx var-counts1-flg (flg rhs arg lst acc)
    (declare (xargs :verify-guards nil
                    :normalize nil
                    :measure (case flg (term (acl2-count rhs))
                               (otherwise (acl2-count lst)))
                    :hints nil
                    :well-founded-relation o<
                    :mode :logic)
             (ignorable rhs arg lst acc))
    (case flg
      (term (cond ((equal arg rhs) (+ 1 acc))
                  ((consp rhs)
                   (cond ((equal 'quote (car rhs)) acc)
                         ((equal (car rhs) 'if)
                          (max (var-counts1-flg 'term
                                                (caddr rhs)
                                                arg nil acc)
                               (var-counts1-flg 'term
                                                (cadddr rhs)
                                                arg nil acc)))
                         (t (var-counts1-flg 'list
                                             nil arg (cdr rhs)
                                             acc))))
                  (t acc)))
      (otherwise (if (consp lst)
                     (var-counts1-flg 'list
                                      nil arg (cdr lst)
                                      (var-counts1-flg 'term
                                                       (car lst)
                                                       arg nil acc))
                   acc)))))
 (local
  (defthm
    var-counts1-flg-equivalences
    (equal (var-counts1-flg flg rhs arg lst acc)
           (case flg (term (var-counts1 arg rhs acc))
             (otherwise (var-counts1-lst arg lst acc))))))
 (local (in-theory (disable (:definition var-counts1-flg))))

;;; (defthm-var-counts1 natp-var-counts1
;;;   (term
;;;    (implies (natp acc)
;;;             (natp (var-counts1 arg rhs acc)))
;;;    :rule-classes :type-prescription)
;;;   (list
;;;    (implies (natp acc)
;;;             (natp (var-counts1-lst arg lst acc)))
;;;    :rule-classes :type-prescription)
;;;   :hints (("Goal" :induct (var-counts1-flg flg rhs arg lst acc))))

 (local
  (defthm natp-var-counts1
    (case flg
      (term (implies (natp acc)
                     (natp (var-counts1 arg rhs acc))))
      (otherwise (implies (natp acc)
                          (natp (var-counts1-lst arg lst acc)))))
    :hints (("Goal" :induct (var-counts1-flg flg rhs arg lst acc)))
    :rule-classes nil))
 (local
  (defthm natp-var-counts1-term
    (implies (natp acc)
             (natp (var-counts1 arg rhs acc)))
    :hints (("Goal" ; :in-theory (theory 'minimal-theory)
             :use ((:instance natp-var-counts1 (flg 'term)))))
    :rule-classes :type-prescription))
 (local
  (defthm natp-var-counts1-list
    (implies (natp acc)
             (natp (var-counts1-lst arg lst acc)))
    :hints (("Goal" ; :in-theory (theory 'minimal-theory)
             :use ((:instance natp-var-counts1 (flg 'list)))))
    :rule-classes :type-prescription))

 (verify-guards var-counts1)

 (verify-termination-boot-strap var-counts) ; and guards

;;; Since the comment about var-counts says that var-counts returns a list of
;;; nats as long as lhs-args, I prove those facts, speculatively.

; Except, we reason instead about integer-listp.  See the comment just above
; the commented-out definition of nat-listp in the source code (file
; rewrite.lisp).
; (verify-termination nat-listp)

 (local
  (defthm integer-listp-var-counts
    (integer-listp (var-counts lhs-args rhs))))

 (local
  (defthm len-var-counts
    (equal (len (var-counts lhs-args rhs))
           (len lhs-args))))

 (verify-termination-boot-strap count-ifs) ; and guards

; Added here (not present or needed in the certified book):
 (verify-termination-boot-strap ifix) ; and guards

; Added here (not present or needed in the certified book):
 (verify-termination-boot-strap abs) ; and guards

; Added here (not present or needed in the certified book):
 (verify-termination-boot-strap expt) ; and guards

; Added here (not present or needed in the certified book):
 (local (defthm natp-expt
          (implies (and (integerp base)
                        (integerp n)
                        (<= 0 n))
                   (integerp (expt base n)))
          :rule-classes :type-prescription))

; Added here (not present or needed in the certified book):
 (verify-termination-boot-strap signed-byte-p) ; and guards

 (verify-termination-boot-strap too-many-ifs0) ; and guards

 (verify-termination-boot-strap too-many-ifs-pre-rewrite-builtin) ; and guards

 (verify-termination-boot-strap occur-cnt-bounded)

;;; (make-flag occur-cnt-bounded-flg
;;;            occur-cnt-bounded
;;;            :flag-var flg
;;;            :flag-mapping ((occur-cnt-bounded term)
;;;                           (occur-cnt-bounded-lst list))
;;;            :defthm-macro-name defthm-occur-cnt-bounded
;;;            :local t)

 (local
  (defun-nx occur-cnt-bounded-flg (flg term2 term1 lst a m bound-m)
    (declare (xargs :verify-guards nil
                    :normalize nil
                    :measure (case flg (term (acl2-count term2))
                               (otherwise (acl2-count lst))))
             (ignorable term2 term1 lst a m bound-m))
    (case flg
      (term (cond ((equal term1 term2)
                   (if (< bound-m a) -1 (+ a m)))
                  ((consp term2)
                   (if (equal 'quote (car term2))
                       a
                     (occur-cnt-bounded-flg 'list
                                            nil term1 (cdr term2)
                                            a m bound-m)))
                  (t a)))
      (otherwise (if (consp lst)
                     (let ((new (occur-cnt-bounded-flg 'term
                                                       (car lst)
                                                       term1 nil a m bound-m)))
                       (if (equal new -1)
                           -1
                         (occur-cnt-bounded-flg 'list
                                                nil term1 (cdr lst)
                                                new m bound-m)))
                   a)))))
 (local
  (defthm occur-cnt-bounded-flg-equivalences
    (equal (occur-cnt-bounded-flg flg term2 term1 lst a m bound-m)
           (case flg
             (term (occur-cnt-bounded term1 term2 a m bound-m))
             (otherwise (occur-cnt-bounded-lst term1 lst a m bound-m))))))
 (local (in-theory (disable (:definition occur-cnt-bounded-flg))))

;;; (defthm-occur-cnt-bounded integerp-occur-cnt-bounded
;;;   (term
;;;    (implies (and (integerp a)
;;;                  (integerp m))
;;;             (integerp (occur-cnt-bounded term1 term2 a m bound-m)))
;;;    :rule-classes :type-prescription)
;;;   (list
;;;    (implies (and (integerp a)
;;;                  (integerp m))
;;;             (integerp (occur-cnt-bounded-lst term1 lst a m bound-m)))
;;;    :rule-classes :type-prescription)
;;;   :hints (("Goal" :induct (occur-cnt-bounded-flg flg term2 term1 lst a m
;;;                                                  bound-m))))

 (local
  (defthm integerp-occur-cnt-bounded
    (case flg
      (term (implies (and (integerp a) (integerp m))
                     (integerp (occur-cnt-bounded term1 term2 a m bound-m))))
      (otherwise
       (implies (and (integerp a) (integerp m))
                (integerp (occur-cnt-bounded-lst term1 lst a m bound-m)))))
    :rule-classes nil
    :hints
    (("Goal" :induct (occur-cnt-bounded-flg flg term2 term1 lst a m bound-m)))))
 (local
  (defthm integerp-occur-cnt-bounded-term
    (implies (and (integerp a) (integerp m))
             (integerp (occur-cnt-bounded term1 term2 a m bound-m)))
    :rule-classes :type-prescription
    :hints (("goal" ; :in-theory (theory 'minimal-theory)
             :use ((:instance integerp-occur-cnt-bounded
                              (flg 'term)))))))
 (local
  (defthm integerp-occur-cnt-bounded-list
    (implies (and (integerp a) (integerp m))
             (integerp (occur-cnt-bounded-lst term1 lst a m bound-m)))
    :rule-classes :type-prescription
    :hints (("goal" ; :in-theory (theory 'minimal-theory)
             :use ((:instance integerp-occur-cnt-bounded
                              (flg 'list)))))))

;;; (defthm-occur-cnt-bounded signed-byte-p-30-occur-cnt-bounded-flg
;;;   (term
;;;    (implies (and (force (signed-byte-p 30 a))
;;;                  (signed-byte-p 30 m)
;;;                  (signed-byte-p 30 (+ bound-m m))
;;;                  (force (<= 0 a))
;;;                  (<= 0 m)
;;;                  (<= 0 bound-m)
;;;                  (<= a (+ bound-m m)))
;;;             (and (<= -1 (occur-cnt-bounded term1 term2 a m bound-m))
;;;                  (<= (occur-cnt-bounded term1 term2 a m bound-m) (+ bound-m m))))
;;;    :rule-classes :linear)
;;;   (list
;;;    (implies (and (force (signed-byte-p 30 a))
;;;                  (signed-byte-p 30 m)
;;;                  (signed-byte-p 30 (+ bound-m m))
;;;                  (force (<= 0 a))
;;;                  (<= 0 m)
;;;                  (<= 0 bound-m)
;;;                  (<= a (+ bound-m m)))
;;;             (and (<= -1 (occur-cnt-bounded-lst term1 lst a m bound-m))
;;;                  (<= (occur-cnt-bounded-lst term1 lst a m bound-m) (+ bound-m m))))
;;;    :rule-classes :linear)
;;;   :hints (("Goal" :induct (occur-cnt-bounded-flg flg term2 term1 lst a m
;;;                                                  bound-m))))

 (local
  (defthm signed-byte-p-30-occur-cnt-bounded-flg
    (case flg
      (term (implies (and (force (signed-byte-p 30 a))
                          (signed-byte-p 30 m)
                          (signed-byte-p 30 (+ bound-m m))
                          (force (<= 0 a))
                          (<= 0 m)
                          (<= 0 bound-m)
                          (<= a (+ bound-m m)))
                     (and (<= -1
                              (occur-cnt-bounded term1 term2 a m bound-m))
                          (<= (occur-cnt-bounded term1 term2 a m bound-m)
                              (+ bound-m m)))))
      (otherwise
       (implies (and (force (signed-byte-p 30 a))
                     (signed-byte-p 30 m)
                     (signed-byte-p 30 (+ bound-m m))
                     (force (<= 0 a))
                     (<= 0 m)
                     (<= 0 bound-m)
                     (<= a (+ bound-m m)))
                (and (<= -1
                         (occur-cnt-bounded-lst term1 lst a m bound-m))
                     (<= (occur-cnt-bounded-lst term1 lst a m bound-m)
                         (+ bound-m m))))))
    :rule-classes nil
    :hints
    (("Goal" :induct (occur-cnt-bounded-flg flg term2 term1 lst a m bound-m)))))
 (local
  (defthm signed-byte-p-30-occur-cnt-bounded-flg-term
    (implies (and (force (signed-byte-p 30 a))
                  (signed-byte-p 30 m)
                  (signed-byte-p 30 (+ bound-m m))
                  (force (<= 0 a))
                  (<= 0 m)
                  (<= 0 bound-m)
                  (<= a (+ bound-m m)))
             (and (<= -1
                      (occur-cnt-bounded term1 term2 a m bound-m))
                  (<= (occur-cnt-bounded term1 term2 a m bound-m)
                      (+ bound-m m))))
    :rule-classes :linear
    :hints (("Goal" ; :in-theory (theory 'minimal-theory)
             :use ((:instance signed-byte-p-30-occur-cnt-bounded-flg
                              (flg 'term)))))))
 (local
  (defthm signed-byte-p-30-occur-cnt-bounded-flg-list
    (implies (and (force (signed-byte-p 30 a))
                  (signed-byte-p 30 m)
                  (signed-byte-p 30 (+ bound-m m))
                  (force (<= 0 a))
                  (<= 0 m)
                  (<= 0 bound-m)
                  (<= a (+ bound-m m)))
             (and (<= -1
                      (occur-cnt-bounded-lst term1 lst a m bound-m))
                  (<= (occur-cnt-bounded-lst term1 lst a m bound-m)
                      (+ bound-m m))))
    :rule-classes :linear
    :hints (("Goal" ; :in-theory (theory 'minimal-theory)
             :use ((:instance signed-byte-p-30-occur-cnt-bounded-flg
                              (flg 'list)))))))

 (verify-guards occur-cnt-bounded)

 (verify-termination-boot-strap too-many-ifs1) ; and guards

 (verify-termination-boot-strap too-many-ifs-post-rewrite-builtin) ; and guards

 )

(defattach too-many-ifs-post-rewrite too-many-ifs-post-rewrite-builtin)

; Complete too-many-ifs-pre-rewrite.

#+acl2-loop-only
; The above readtime conditional avoids a CLISP warning, and lets the defproxy
; for print-clause-id-okp provide the raw Lisp definition.
(encapsulate
  ((too-many-ifs-pre-rewrite (args counts) t
                             :guard
                             (and (pseudo-term-listp args)
                                  (integer-listp counts)
                                  (equal (len args) (len counts)))))
  (local (defun too-many-ifs-pre-rewrite (args counts)
           (list args counts))))

(defattach (too-many-ifs-pre-rewrite too-many-ifs-pre-rewrite-builtin))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Attachment: ancestors-check, worse-than, worse-than-or-equal
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(verify-termination-boot-strap pseudo-variantp)

(verify-termination-boot-strap member-char-stringp)

(verify-termination-boot-strap terminal-substringp1)

(verify-termination-boot-strap terminal-substringp)

(verify-termination-boot-strap evg-occur)

(verify-termination-boot-strap min-fixnum)

(verify-termination-boot-strap fn-count-evg-rec ; but not guards
                               (declare (xargs :verify-guards nil)))

(defthm fn-count-evg-rec-type-prescription
  (implies (natp acc)
           (natp (fn-count-evg-rec evg acc calls)))
  :rule-classes :type-prescription)

(defthm fn-count-evg-rec-bound
  (< (fn-count-evg-rec evg acc calls)
     536870912) ; (expt 2 29)
  :rule-classes :linear)

(verify-guards fn-count-evg-rec)

(verify-termination-boot-strap occur)

(verify-termination-boot-strap worse-than-builtin-clocked) ; and mut-rec nest

(verify-termination-boot-strap worse-than-builtin)

(verify-termination-boot-strap worse-than-or-equal-builtin)

(verify-termination-boot-strap ancestor-listp)

(verify-termination-boot-strap earlier-ancestor-biggerp)

(verify-termination-boot-strap fn-count-1) ; but not guards

(defthm fn-count-1-type
  (implies (and (integerp fn-count-acc)
                (integerp p-fn-count-acc))
           (and (integerp (car (fn-count-1 flag term
                                           fn-count-acc p-fn-count-acc)))
                (integerp (mv-nth 0 (fn-count-1 flag term
                                                fn-count-acc
                                                p-fn-count-acc)))
                (integerp (mv-nth 1 (fn-count-1 flag term
                                                fn-count-acc
                                                p-fn-count-acc)))
                (integerp (nth 0 (fn-count-1 flag term
                                             fn-count-acc
                                             p-fn-count-acc)))
                (integerp (nth 1 (fn-count-1 flag term
                                             fn-count-acc
                                             p-fn-count-acc)))))
  :rule-classes ((:forward-chaining
                  :trigger-terms
                  ((fn-count-1 flag term fn-count-acc p-fn-count-acc)))))

(verify-guards fn-count-1)

(verify-termination-boot-strap var-fn-count-1) ; but not guards

(defthm symbol-listp-cdr-assoc-equal
  (implies (symbol-list-listp x)
           (symbol-listp (cdr (assoc-equal key x)))))

; We state the following three rules in all forms that we think might be useful
; to those who want to reason about var-fn-count-1, for example if they are
; developing attachments to ancestors-check.

(defthm integerp-nth-0-var-fn-count-1
  (implies (integerp var-count-acc)
           (integerp (nth 0 (var-fn-count-1
                             flg x
                             var-count-acc fn-count-acc p-fn-count-acc
                             invisible-fns invisible-fns-table))))
  :rule-classes
  ((:forward-chaining
    :trigger-terms
    ((var-fn-count-1 flg x var-count-acc fn-count-acc
                     p-fn-count-acc invisible-fns
                     invisible-fns-table))
    :corollary
    (implies (integerp var-count-acc)
             (and (integerp (nth 0 (var-fn-count-1
                                    flg x
                                    var-count-acc fn-count-acc p-fn-count-acc
                                    invisible-fns invisible-fns-table)))
                  (integerp (mv-nth 0 (var-fn-count-1
                                       flg x
                                       var-count-acc fn-count-acc p-fn-count-acc
                                       invisible-fns invisible-fns-table)))
                  (integerp (car (var-fn-count-1
                                  flg x
                                  var-count-acc fn-count-acc p-fn-count-acc
                                  invisible-fns invisible-fns-table))))))))

(defthm integerp-nth-1-var-fn-count-1
  (implies (integerp fn-count-acc)
           (integerp (nth 1 (var-fn-count-1
                             flg x
                             var-count-acc fn-count-acc p-fn-count-acc
                             invisible-fns invisible-fns-table))))
  :rule-classes
  ((:forward-chaining
    :trigger-terms
    ((var-fn-count-1 flg x var-count-acc fn-count-acc
                     p-fn-count-acc invisible-fns
                     invisible-fns-table))
    :corollary
    (implies (integerp fn-count-acc)
             (and (integerp (nth 1 (var-fn-count-1
                                       flg x
                                       var-count-acc fn-count-acc p-fn-count-acc
                                       invisible-fns invisible-fns-table)))
                  (integerp (mv-nth 1 (var-fn-count-1
                                       flg x
                                       var-count-acc fn-count-acc p-fn-count-acc
                                       invisible-fns invisible-fns-table))))))))

(defthm integerp-nth-2-var-fn-count-1
  (implies (integerp p-fn-count-acc)
           (integerp (nth 2 (var-fn-count-1
                             flg x
                             var-count-acc fn-count-acc p-fn-count-acc
                             invisible-fns invisible-fns-table))))
  :rule-classes
  ((:forward-chaining
    :trigger-terms
    ((var-fn-count-1 flg x var-count-acc fn-count-acc
                     p-fn-count-acc invisible-fns
                     invisible-fns-table))
    :corollary
    (implies (integerp p-fn-count-acc)
             (and (integerp (nth 2 (var-fn-count-1
                                    flg x
                                    var-count-acc fn-count-acc p-fn-count-acc
                                    invisible-fns invisible-fns-table)))
                  (integerp (mv-nth 2 (var-fn-count-1
                                       flg x
                                       var-count-acc fn-count-acc p-fn-count-acc
                                       invisible-fns invisible-fns-table))))))))

(verify-guards var-fn-count-1)

(verify-termination-boot-strap equal-mod-commuting) ; and guards

(verify-termination-boot-strap ancestors-check1)

(verify-termination-boot-strap ancestors-check-builtin)

(defun member-equal-mod-commuting (x lst wrld)
  (declare (xargs :guard (and (pseudo-termp x)
                              (pseudo-term-listp lst)
                              (plist-worldp wrld))))
  (cond ((endp lst) nil)
        ((equal-mod-commuting x (car lst) wrld) lst)
        (t (member-equal-mod-commuting x (cdr lst) wrld))))

; In the following, terms (nth 0 ...) and (nth 1 ...) in the hints were
; originally (car ...) and (mv-nth 1 ...), respectively, but those didn't
; work.  It would be good at some point to explore why not, given that the
; original versions worked outside the build.

(defun strip-ancestor-literals (ancestors)
  (declare (xargs :guard (ancestor-listp ancestors)))
  (cond ((endp ancestors) nil)
        (t (cons (access ancestor (car ancestors) :lit)
                 (strip-ancestor-literals (cdr ancestors))))))

(encapsulate
 ()

 (local
  (defthm ancestors-check1-property
    (mv-let (on-ancestors assumed-true)
            (ancestors-check1 lit-atm lit var-cnt fn-cnt p-fn-cnt ancestors
                              tokens)
            (implies (and on-ancestors
                          assumed-true)
                     (member-equal-mod-commuting
                      lit
                      (strip-ancestor-literals ancestors)
                      nil)))
    :rule-classes nil))

 (defthmd ancestors-check-builtin-property
   (mv-let (on-ancestors assumed-true)
           (ancestors-check-builtin lit ancestors tokens)
           (implies (and on-ancestors
                         assumed-true)
                    (member-equal-mod-commuting
                     lit
                     (strip-ancestor-literals ancestors)
                     nil)))
   :hints (("Goal"
            :use
            ((:instance
              ancestors-check1-property
              (lit-atm lit)
              (var-cnt 0)
              (fn-cnt 0)
              (p-fn-cnt 0))
             (:instance
              ancestors-check1-property
              (lit-atm lit)
              (var-cnt (nth 0 (var-fn-count-1 nil lit 0 0 0 nil nil)))
              (fn-cnt (nth 1 (var-fn-count-1 nil lit 0 0 0 nil nil)))
              (p-fn-cnt (nth 2 (var-fn-count-1 nil lit 0 0 0 nil nil))))
             (:instance
              ancestors-check1-property
              (lit-atm (cadr lit))
              (var-cnt (nth 0 (var-fn-count-1 nil (cadr lit) 0 0 0 nil nil)))
              (fn-cnt (nth 1 (var-fn-count-1 nil (cadr lit) 0 0 0 nil nil)))
              (p-fn-cnt (nth 2
                             (var-fn-count-1 nil (cadr lit) 0 0 0
                                             nil nil)))))))))

#+acl2-loop-only
; The above readtime conditional avoids a CLISP warning, and lets the defproxy
; for print-clause-id-okp provide the raw Lisp definition.
(encapsulate
 ((ancestors-check (lit ancestors tokens) (mv t t)
                   :guard (and (pseudo-termp lit)
                               (ancestor-listp ancestors)
                               (true-listp tokens))))

 (local (defun ancestors-check (lit ancestors tokens)
          (ancestors-check-builtin lit ancestors tokens)))

 (defthmd ancestors-check-constraint
   (implies (and (pseudo-termp lit)
                 (ancestor-listp ancestors)
                 (true-listp tokens))
            (mv-let (on-ancestors assumed-true)
                    (ancestors-check lit ancestors tokens)
                    (implies (and on-ancestors
                                  assumed-true)
                             (member-equal-mod-commuting
                              lit
                              (strip-ancestor-literals ancestors)
                              nil))))
   :hints (("Goal" :use ancestors-check-builtin-property))))

(defattach (ancestors-check ancestors-check-builtin)
  :hints (("Goal" :by ancestors-check-builtin-property)))

(defattach worse-than worse-than-builtin)

(defattach worse-than-or-equal worse-than-or-equal-builtin)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Attachment: acl2x-expansion-alist
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(verify-termination-boot-strap hons-copy-with-state) ; and guards

(verify-termination-boot-strap identity-with-state) ; and guards

(defattach (acl2x-expansion-alist
; User-modifiable; see comment in the defstub introducing
; acl2x-expansion-alist.
            identity-with-state))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Attachments: rw-cache utilities
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(verify-termination-boot-strap rw-cache-debug-builtin) ; and guards

(defattach rw-cache-debug rw-cache-debug-builtin)

(verify-termination-boot-strap rw-cache-debug-action-builtin) ; and guards

(defattach rw-cache-debug-action rw-cache-debug-action-builtin)

(verify-termination-boot-strap rw-cacheable-failure-reason-builtin) ; and guards

(defattach rw-cacheable-failure-reason rw-cacheable-failure-reason-builtin)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Attachments: print-clause-id-okp
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(verify-termination-boot-strap all-digits-p) ; and guards

(verify-termination-boot-strap ; and guards
 (d-pos-listp
  (declare
   (xargs
    :guard-hints
    (("Goal"
      :use ((:instance coerce-inverse-2
                       (x (symbol-name (car lst))))
            (:instance character-listp-coerce
                       (str (symbol-name (car lst)))))
      :expand ((len (coerce (symbol-name (car lst)) 'list)))
      :in-theory (disable coerce-inverse-2
                          character-listp-coerce)))))))

(verify-termination-boot-strap pos-listp)
(verify-guards pos-listp)

(defthm d-pos-listp-forward-to-true-listp
  (implies (d-pos-listp x)
           (true-listp x))
  :rule-classes :forward-chaining)

(verify-termination-boot-strap clause-id-p) ; and guards

#+acl2-loop-only
; The above readtime conditional avoids a CLISP warning, and lets the defproxy
; for print-clause-id-okp provide the raw Lisp definition.
(encapsulate
 (((print-clause-id-okp *) => * :formals (cl-id) :guard (clause-id-p cl-id)))
 (local (defun print-clause-id-okp (x)
          x)))

(verify-termination-boot-strap print-clause-id-okp-builtin) ; and guards

(defattach print-clause-id-okp print-clause-id-okp-builtin)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Attachments: oncep-tp
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; We could avoid the forms below by replacing the earlier forms
;   (defproxy oncep-tp (* *) => *)
;   (defun oncep-tp-builtin ...) ; :guard t
;   (defattach (oncep-tp oncep-tp-builtin) :skip-checks t)
; in place, by changing defproxy to defstub and removing :skip-checks t.
; However, the guard on once-tp would then be left with a guard of t, which
; might be stronger than we'd like.

#+acl2-loop-only
; The above readtime conditional avoids a CLISP warning, and lets the defproxy
; for print-clause-id-okp provide the raw Lisp definition.
(encapsulate
 (((oncep-tp * *) => *
   :formals (rune wrld)
   :guard (and (plist-worldp wrld)

; Although (runep rune wrld) is appropriate here, we don't want to fight the
; battle yet of putting runep into :logic mode.  So we just lay down the
; syntactic part of its code, which should suffice for user-defined attachments
; to oncep-tp.

               (and (consp rune)
                    (consp (cdr rune))
                    (symbolp (cadr rune))))))
 (logic)
 (local (defun oncep-tp (rune wrld)
          (oncep-tp-builtin rune wrld))))

(defattach oncep-tp oncep-tp-builtin)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; verify-termination and guard verification:
; string-for-tilde-@-clause-id-phrase and some subsidiary functions
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; David Rager proved termination and guards for
; string-for-tilde-@-clause-id-phrase, with a proof that included community
; books unicode/explode-atom and unicode/explode-nonnegative-integer.  Here, we
; rework that proof a bit to avoid those dependencies.  Note that this proof
; depends on d-pos-listp, whose termination and guard verification are
; performed above.

; We proved true-listp-explode-nonnegative-integer here, but then found it was
; already proved locally in axioms.lisp.  So we made that defthm non-local (and
; strengthened it to its current form).

(verify-termination-boot-strap chars-for-tilde-@-clause-id-phrase/periods)

(verify-termination-boot-strap chars-for-tilde-@-clause-id-phrase/primes)

(defthm pos-listp-forward-to-integer-listp
  (implies (pos-listp x)
           (integer-listp x))
  :rule-classes :forward-chaining)

(verify-termination-boot-strap chars-for-tilde-@-clause-id-phrase)

(defthm true-listp-chars-for-tilde-@-clause-id-phrase/periods
  (true-listp (chars-for-tilde-@-clause-id-phrase/periods lst))
  :rule-classes :type-prescription)

(defthm true-listp-explode-atom
  (true-listp (explode-atom n print-base))
  :rule-classes :type-prescription)

(encapsulate
 ()

; The following local events create perfectly good rewrite rules, but we avoid
; the possibility of namespace clashes for existing books by making them local
; as we add them after Version_4.3.

 (local
  (defthm character-listp-explode-nonnegative-integer
    (implies
     (character-listp ans)
     (character-listp (explode-nonnegative-integer n print-base ans)))))

 (local
  (defthm character-listp-explode-atom
    (character-listp (explode-atom n print-base))
    :hints ; need to disable this local lemma from axioms.lisp
    (("Goal" :in-theory (disable character-listp-cdr)))))

 (local
  (defthm character-listp-chars-for-tilde-@-clause-id-phrase/periods
    (character-listp (chars-for-tilde-@-clause-id-phrase/periods lst))))

 (verify-termination-boot-strap string-for-tilde-@-clause-id-phrase))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; verify-termination and guard verification:
; strict-merge-symbol<, strict-merge-sort-symbol<, strict-symbol<-sortedp,
; and sort-symbol-listp
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(verify-termination-boot-strap strict-merge-symbol<
                               (declare (xargs :measure
                                               (+ (len l1) (len l2)))))

(encapsulate
 ()

 (local
  (defthm len-strict-merge-symbol<
    (<= (len (strict-merge-symbol< l1 l2 acc))
        (+ (len l1) (len l2) (len acc)))
    :rule-classes :linear))

 (local
  (defthm len-evens
    (equal (len l)
           (+ (len (evens l))
              (len (odds l))))
    :rule-classes :linear))

 (local
  (defthm symbol-listp-evens
    (implies (symbol-listp x)
             (symbol-listp (evens x)))
    :hints (("Goal" :induct (evens x)))))

 (local
  (defthm symbol-listp-odds
    (implies (symbol-listp x)
             (symbol-listp (odds x)))))

 (local
  (defthm symbol-listp-strict-merge-symbol<
    (implies (and (symbol-listp l1)
                  (symbol-listp l2)
                  (symbol-listp acc))
             (symbol-listp (strict-merge-symbol< l1 l2 acc)))))

 (verify-termination-boot-strap strict-merge-sort-symbol<
                                (declare (xargs :measure (len l)
                                                :verify-guards nil)))

 (defthm symbol-listp-strict-merge-sort-symbol<
; This lemma is non-local because it is needed for "make proofs", for
; guard-verification for new-verify-guards-fns1.
   (implies (symbol-listp x)
            (symbol-listp (strict-merge-sort-symbol< x))))

 (verify-guards strict-merge-sort-symbol<)

 (verify-termination-boot-strap sort-symbol-listp) ; and guards

 )

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; verify-termination and guard verification:
; ld-history and associated functions
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(verify-termination-boot-strap ld-history) ; and guards
(verify-termination-boot-strap ld-history-entry-input) ; and guards
(verify-termination-boot-strap ld-history-entry-error-flg) ; and guards
(verify-termination-boot-strap ld-history-entry-stobjs-out/value) ; and guards
(verify-termination-boot-strap ld-history-entry-stobjs-out) ; and guards
(verify-termination-boot-strap ld-history-entry-value) ; and guards
(verify-termination-boot-strap ld-history-entry-user-data) ; and guards
(verify-termination-boot-strap
 set-ld-history-entry-user-data-default)

(defattach set-ld-history-entry-user-data
  set-ld-history-entry-user-data-default)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Theories
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(deftheory definition-minimal-theory
  (definition-runes
    *definition-minimal-theory*
    nil
    world))

(deftheory executable-counterpart-minimal-theory
  (definition-runes
    *built-in-executable-counterparts*
    t
    world))

(deftheory minimal-theory

; Warning: The resulting value must be a runic-theoryp.  See
; theory-fn-callp.

; Keep this definition in sync with translate-in-theory-hint.

  (union-theories (theory 'definition-minimal-theory)
                  (union-theories

; Without the :executable-counterpart of force, the use of (theory
; 'minimal-theory) will produce the warning "Forcing has transitioned from
; enabled to disabled", at least if forcing is enabled (as is the default).
; Moreover, it's not unreasonable to leave forcing on in the minimal-theory,
; for example in case it's useful for linear arithmetic.

                   '((:executable-counterpart force))
                   (theory 'executable-counterpart-minimal-theory))))

(defconst *acl2-primitives*
  (strip-cars *primitive-formals-and-guards*))

(deftheory acl2-primitives
  (definition-runes *acl2-primitives* nil world))

; See the Essay on the Status of the Tau System During and After Bootstrapping
; in axioms.lisp where we discuss choices (1.a), (1.b), (2.a) and (2.b)
; related to the status of the tau system.  Here is where we implement
; (2.a).

(in-theory (if (cadr *tau-status-boot-strap-settings*)          ; (2.a)
               (enable (:executable-counterpart tau-system))
               (disable (:executable-counterpart tau-system))))

; Avoid ugly output from, e.g., (thm (equal (print-call-history) 3)).
(in-theory (disable (:e print-call-history)))

; Alessandro Coglio observed significant speed-up from the following disable.
(in-theory (disable ctxp))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; meta-extract support
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(verify-termination-boot-strap formals) ; and guards
(verify-termination-boot-strap constraint-info) ; and guards
(verify-termination-boot-strap unknown-constraints-p) ; and guards

(defund meta-extract-formula (name state)

; This function supports meta-extract-global-fact+.  It needs to be executable
; and in :logic mode (hence, as required by the ACL2 build process,
; guard-verified), since it may be called by meta functions.

; While this function can be viewed as a version of formula, it applies only to
; symbols (not runes), it is in :logic mode, and there are a few other
; differences as well.  The present function requires name to be a symbol and
; only returns a normalp=nil form of body.  (Otherwise, in order to put body in
; :logic mode, body would need to be guard-verified, which would probably take
; considerable effort.)

  (declare (xargs :stobjs state
                  :guard (symbolp name)))
  (let ((wrld (w state)))
    (or (getpropc name 'theorem nil wrld)
        (cond ((logicp name wrld)
               (mv-let (flg prop)
                 (constraint-info name wrld)
                 (cond ((unknown-constraints-p prop)
                        *t*)
                       (flg (ec-call (conjoin prop)))
                       (t prop))))
              (t *t*)))))

(verify-termination-boot-strap type-set-quote)
(verify-guards type-set-quote)

(defun typespec-check (ts x)
  (declare (xargs :guard (integerp ts)))
  (if (bad-atom x)
      (< ts 0) ; bad-atom type intersects every complement type

; We would like to write
;   (ts-subsetp (type-set-quote x) ts)
; here, but for that we need a stronger guard than (integerp ts), and we prefer
; to keep this simple.

    (not (eql 0 (logand (type-set-quote x) ts)))))

(defun meta-extract-rw+-term (term alist equiv rhs state)

; This function supports the function meta-extract-contextual-fact.  Neither of
; these functions is intended to be executed.

; Meta-extract-rw+-term creates (logically) a term claiming that term under
; alist is equiv to rhs, where equiv=nil represents 'equal and equiv=t
; represents 'iff.  If equiv is not t, nil, or an equivalence relation, then
; *t* is returned.

; Note that this function does not support the use of a geneqv for the equiv
; argument.

  (declare (xargs :mode :program ; becomes :logic with system-verify-guards
                  :stobjs state
                  :guard (and (symbol-alistp alist)
                              (pseudo-term-listp (strip-cdrs alist))
                              (pseudo-termp term))))
  (non-exec
   (let ((lhs (sublis-var alist term)))
     (case equiv
       ((nil) `(equal ,lhs ,rhs))
       ((t)   `(iff ,lhs ,rhs))
       (otherwise
        (if (symbolp equiv)
            (if (equivalence-relationp equiv (w state))
                `(,equiv ,lhs ,rhs)
; else bad equivalence relation
              *t*)
          *t*))))))

(defun meta-extract-contextual-fact (obj mfc state)

; This function is not intended to be executed.

; This function may be called in the hypothesis of a meta rule, because we know
; it always produces a term that evaluates to non-nil under the mfc where the
; metafunction is called, using the specific alist A for which we're proving
; (evl x a) = (evl (metafn x) a).  The terms it produces reflect the
; correctness of certain prover operations -- currently, accessing type-alist
; and typeset information, rewriting, and linear arithmetic.  See the Essay on
; Correctness of Meta Reasoning.  Note that these operations use the state for
; heuristic purposes, and get their logical information from the world stored
; in mfc (not in state).

; This function avoids forcing and does not return a tag-tree.

  (declare (xargs :mode :program ; becomes :logic with system-verify-guards
                  :stobjs state))
  (non-exec
   (case-match obj
     ((':typeset term . &) ; mfc-ts produces correct results
      `(typespec-check
        ',(mfc-ts term mfc state :forcep nil :ttreep nil)
        ,term))
     ((':rw+ term alist obj equiv . &) ; result is equiv to term/alist.
      (meta-extract-rw+-term term alist equiv
                             (mfc-rw+ term alist obj equiv mfc state
                                      :forcep nil :ttreep nil)
                             state))
     ((':rw term obj equiv . &) ; as for :rw+, with alist of nil
      (meta-extract-rw+-term term nil equiv
                             (mfc-rw term obj equiv mfc state
                                     :forcep nil :ttreep nil)
                             state))
     ((':ap term . &) ; Can linear arithmetic can falsify term?
      (if (mfc-ap term mfc state :forcep nil)
          `(not ,term)
        *t*))
     ((':relieve-hyp hyp alist rune target bkptr . &) ; hyp/alist proved?
      (if (mfc-relieve-hyp hyp alist rune target bkptr mfc state
                           :forcep nil :ttreep nil)
          (sublis-var alist hyp)
        *t*))
     (& *t*))))

(defun rewrite-rule-term-exec (x)
  (declare (xargs :guard (and (weak-rewrite-rule-p x)
                              (or (eq (access rewrite-rule x :subclass) 'meta)
                                  (true-listp (access rewrite-rule x :hyps))))))
  (if (eq (access rewrite-rule x :subclass) 'meta)
      *t*
    `(implies ,(conjoin (access rewrite-rule x :hyps))
              (,(access rewrite-rule x :equiv)
               ,(access rewrite-rule x :lhs)
               ,(access rewrite-rule x :rhs)))))

(defun rewrite-rule-term (x)

; This function turns a rewrite-rule record into a term.  Consider using
; rewrite-rule-term-exec instead when its guard doesn't cause problems.

  (declare (xargs :guard t))
  (ec-call (rewrite-rule-term-exec x)))

(defmacro meta-extract-global-fact (obj state)
; See meta-extract-global-fact+.
   `(meta-extract-global-fact+ ,obj ,state ,state))

(defun fncall-term (fn arglist state)
  (declare (xargs :stobjs state
                  :guard (and (symbolp fn)
                              (true-listp arglist))))
  (cond ((logicp fn (w state))
         (mv-let (erp val)
           (magic-ev-fncall fn arglist state
                            t  ; hard-error-returns-nilp
                            nil ; aok
                            )
           (cond (erp *t*)
                 (t (fcons-term* 'equal

; As suggested by Sol Swords, we use fcons-term below in order to avoid having
; to reason about the application of an evaluator to (cons-term fn ...).

                                 (fcons-term fn (kwote-lst arglist))
                                 (kwote val))))))
        (t *t*)))

(defun logically-equivalent-states (st1 st2)
   (declare (xargs :guard t))
   (non-exec (equal (w st1) (w st2))))

(defun meta-extract-global-fact+ (obj st state)

; This function is not intended to be executed.

; This function may be called in the hypothesis of a meta rule, because we know
; it always produces a term that evaluates to non-nil for any alist.  The terms
; it produces reflect the correctness of certain facts stored in the world.
; See the Essay on Correctness of Meta Reasoning.

  (declare (xargs :mode :program ; becomes :logic with system-verify-guards
                  :stobjs state))
  (non-exec
   (cond
    ((logically-equivalent-states st state)
     (case-match obj
       ((':formula name)
        (meta-extract-formula name st))
       ((':lemma fn n)
        (let* ((lemmas (getpropc fn 'lemmas nil (w st)))
               (rule (nth n lemmas)))

; The use of rewrite-rule-term below relies on the fact that the 'LEMMAS
; property of a symbol in the ACL2 world is a list of rewrite-rule records that
; reflect known facts.

          (if (< (nfix n) (len lemmas))
              (rewrite-rule-term rule)
            *t*))) ; Fn doesn't exist or n is too big.
       ((':fncall fn arglist)
        (non-exec ; avoid guard check
         (fncall-term fn arglist st)))
       (& *t*)))
    (t *t*))))

(add-macro-alias meta-extract-global-fact meta-extract-global-fact+)