/usr/share/acl2-6.3/books/str/strtok.lisp is in acl2-books-source 6.3-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | ; ACL2 String Library
; Copyright (C) 2009-2013 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/
;
; This program is free software; you can redistribute it and/or modify it under
; the terms of the GNU General Public License as published by the Free Software
; Foundation; either version 2 of the License, or (at your option) any later
; version. 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 GNU General Public License for
; more details. You should have received a copy of the GNU General Public
; License along with this program; if not, write to the Free Software
; Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA.
;
; Original author: Jared Davis <jared@centtech.com>
(in-package "STR")
(include-book "cat")
(include-book "eqv")
(local (include-book "misc/assert" :dir :system))
(local (include-book "arithmetic"))
(local (include-book "std/lists/revappend" :dir :system))
(defsection strtok-aux
:parents (strtok)
:short "Fast implementation of @(see strtok)."
(defund strtok-aux (x n xl delimiters curr acc)
;; x is the string we're tokenizing, xl is its length
;; n is our current position in x
;; delimiters are the list of chars to split on
;; curr is the current word we're accumulating in reverse order
;; acc is the string list of previously found words
(declare (type string x)
(type (integer 0 *) n xl)
(xargs :guard (and (stringp x)
(natp xl)
(natp n)
(= xl (length x))
(<= n xl)
(character-listp delimiters)
(character-listp curr)
(string-listp acc))
:measure (nfix (- (nfix xl) (nfix n)))))
(if (mbe :logic (zp (- (nfix xl) (nfix n)))
:exec (int= n xl))
(if curr
(cons (rchars-to-string curr) acc)
acc)
(let* ((char1 (char x n))
(matchp (member char1 delimiters)))
(strtok-aux (the string x)
(the (integer 0 *) (+ 1 (lnfix n)))
(the integer xl)
delimiters
(if matchp nil (cons char1 curr))
(if (and matchp curr)
(cons (rchars-to-string curr) acc)
acc)))))
(local (in-theory (enable strtok-aux)))
(defthm true-listp-of-strtok-aux
(implies (true-listp acc)
(true-listp (strtok-aux x n xl delimiters curr acc)))
:hints(("Goal" :induct (strtok-aux x n xl delimiters curr acc))))
(defthm string-listp-of-strtok-aux
(implies (string-listp acc)
(string-listp (strtok-aux x n xl delimiters curr acc)))
:hints(("Goal" :induct (strtok-aux x n xl delimiters curr acc))))
(defcong streqv equal (strtok-aux x n xl delimiters curr acc) 1))
(defsection strtok
:parents (str)
:short "Tokenize a string with character delimiters."
:long "<p>@(call strtok) splits the string @('x') into a list of substrings,
based on @('delimiters'), a list of characters. This is somewhat similar to
repeatedly calling the @('strtok') function in C.</p>
<p>As an example:</p>
@({
(strtok \"foo bar, baz!\" (list #\\Space #\\, #\\!))
-->
(\"foo\" \"bar\" \"baz\")
})
<p>Note that all of the characters in @('delimiters') are removed, and no empty
strings are ever found in @('strtok')'s output.</p>"
(definlined strtok (x delimiters)
(declare (xargs :guard (and (stringp x)
(character-listp delimiters))))
;; Two tricks.
;; - Use REV for better type-prescription
;; - Use LEN of EXPLODE for better congruence
(let ((rtokens (strtok-aux x 0 (mbe :logic (len (explode x))
:exec (length x))
delimiters nil nil)))
(mbe :logic (rev rtokens)
:exec (reverse rtokens))))
(local (in-theory (enable strtok)))
(local (defthm lemma
(implies (string-listp x)
(string-listp (acl2::rev x)))))
(defthm string-listp-of-strtok
(string-listp (strtok x delimiters)))
(defcong streqv equal (strtok x delimiters) 1)
(local
(acl2::assert!
(equal (strtok "foo bar
baz,
heyo,
beyo"
(list #\Space #\, #\Newline))
(list "foo" "bar" "baz" "heyo" "beyo")))))
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