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; Copyright (C) 2013 Centaur Technology
;
; Contact:
; Centaur Technology Formal Verification Group
; 7600-C N. Capital of Texas Highway, Suite 300, Austin, TX 78731, USA.
; http://www.centtech.com/
;
; License: (An MIT/X11-style license)
;
; Permission is hereby granted, free of charge, to any person obtaining a
; copy of this software and associated documentation files (the "Software"),
; to deal in the Software without restriction, including without limitation
; the rights to use, copy, modify, merge, publish, distribute, sublicense,
; and/or sell copies of the Software, and to permit persons to whom the
; Software is furnished to do so, subject to the following conditions:
;
; The above copyright notice and this permission notice shall be included in
; all copies or substantial portions of the Software.
;
; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
; DEALINGS IN THE SOFTWARE.
;
; Original author: Sol Swords <sswords@centtech.com>
(in-package "ACL2")
;; A set of utility functions for finding or collecting subterms of a
;; term/clause that match some pattern.
(include-book "unify-subst")
;; Find one occurrence of a matching term. Don't look
;; in lambda bodies. Return the subterm.
(mutual-recursion
(defun find-match (pat x initial-alist)
(declare (xargs :guard (and (pseudo-termp pat)
(pseudo-termp x)
(alistp initial-alist))))
(b* (((mv match ?alist) (simple-one-way-unify pat x initial-alist))
((when match) (mv t x))
((when (or (variablep x) (fquotep x))) (mv nil nil)))
(find-match-list pat (cdr x) initial-alist)))
(defun find-match-list (pat x initial-alist)
(declare (xargs :guard (and (pseudo-termp pat)
(pseudo-term-listp x)
(alistp initial-alist))))
(b* (((when (atom x)) (mv nil nil))
((mv ok subterm) (find-match pat (car x) initial-alist))
((when ok) (mv ok subterm)))
(find-match-list pat (cdr x) initial-alist))))
;; This variant finds a literal in the clause that matches
(defun find-matching-literal-in-clause (pat clause initial-alist)
(declare (xargs :guard (and (pseudo-termp pat)
(pseudo-term-listp clause)
(alistp initial-alist))))
(b* (((when (atom clause)) (mv nil nil))
((mv match ?alist) (simple-one-way-unify pat (car clause)
initial-alist))
((when match) (mv t (car clause))))
(find-matching-literal-in-clause pat (cdr clause) initial-alist)))
;; Find as many occurrences as exist; return the list of subterms.
(mutual-recursion
(defun find-matches (pat x initial-alist)
(declare (xargs :guard (and (pseudo-termp pat)
(pseudo-termp x)
(alistp initial-alist))))
(b* (((mv match ?alist) (simple-one-way-unify pat x initial-alist))
((when (or (variablep x) (fquotep x)))
(and match (list x)))
(rest (find-matches-list pat (cdr x) initial-alist)))
(if match
(cons x rest)
rest)))
(defun find-matches-list (pat x initial-alist)
(declare (xargs :guard (and (pseudo-termp pat)
(pseudo-term-listp x)
(alistp initial-alist))))
(if (atom x)
nil
(append (find-matches pat (car x) initial-alist)
(find-matches-list pat (cdr x) initial-alist)))))
(flag::make-flag find-matches-flg find-matches)
(defthm-find-matches-flg
(defthm pseudo-termp-find-match
(implies (pseudo-termp x)
(pseudo-termp (mv-nth 1 (find-match pat x initial-alist))))
:flag find-matches)
(defthm pseudo-termp-find-match-list
(implies (pseudo-term-listp x)
(pseudo-termp (mv-nth 1 (find-match-list pat x initial-alist))))
:flag find-matches-list))
(defthm-find-matches-flg
(defthm pseudo-term-listp-find-matches
(implies (pseudo-termp x)
(pseudo-term-listp (find-matches pat x initial-alist)))
:flag find-matches)
(defthm pseudo-term-listp-find-matches-list
(implies (pseudo-term-listp x)
(pseudo-term-listp (find-matches-list pat x initial-alist)))
:flag find-matches-list))
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