/usr/share/acl2-6.3/books/str/strsubst.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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | ; 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 "strprefixp")
(local (include-book "misc/assert" :dir :system))
(local (include-book "arithmetic"))
(defsection strsubst-aux
:parents (strsubst)
:short "Fast implementation of @(see strsubst)."
(defund strsubst-aux (old new x n xl oldl acc)
(declare (type string old new x)
(type (integer 0 *) n xl oldl)
(xargs :guard (and (stringp old)
(stringp new)
(stringp x)
(natp n)
(natp xl)
(posp oldl)
(= oldl (length old))
(= xl (length x)))
:measure (nfix (- (nfix xl) (nfix n)))))
(cond ((mbe :logic (zp oldl)
:exec nil)
acc)
((mbe :logic (zp (- (nfix xl) (nfix n)))
:exec (>= n xl))
acc)
((strprefixp-impl old x 0 n oldl xl)
(let ((acc (revappend-chars new acc)))
(strsubst-aux old new x
(the (integer 0 *)
(+ oldl (the (integer 0 *) (lnfix n))))
xl oldl acc)))
(t
(let ((acc (cons (char x n) acc)))
(strsubst-aux old new x
(the (integer 0 *)
(+ 1 (the (integer 0 *) (lnfix n))))
xl oldl acc)))))
(local (in-theory (enable strsubst-aux)))
(defthm character-listp-of-strsubst-aux
(implies (and (stringp old)
(stringp new)
(stringp x)
(natp n)
(natp xl)
(posp oldl)
(= oldl (length old))
(= xl (length x))
(character-listp acc))
(character-listp (strsubst-aux old new x n xl oldl acc)))))
(defsection strsubst
:parents (substitution substitute)
:short "Replace substrings throughout a string."
:long "<p>@(call strsubst) replaces each occurrence of @('old') with @('new')
throughout @('x'). Each argument is a string, and a new string is returned.
The replacement is done globally and non-recursively.</p>
<p>Examples:</p>
@({
(strsubst \"World\" \"Star\" \"Hello, World!\")
-->
\"Hello, Star!\"
(strsubst \"oo\" \"aa\" \"xoooyoo\")
-->
\"xaaoyaa\"
})
<p>ACL2 has a built in @(see substitute) function, but it only works on
individual characters, whereas @('strsubst') works on substrings.</p>"
;; BOZO probably worthwhile to check if old occurs, and if not don't bother to
;; do any coercion, etc.
(defund strsubst (old new x)
(declare (xargs :guard (and (stringp old)
(stringp new)
(stringp x))))
(let ((oldl (mbe :logic (len (explode old))
:exec (length old))))
(if (zp oldl)
(mbe :logic (str-fix x)
:exec x)
(rchars-to-string (strsubst-aux old new x 0 (length x) oldl nil)))))
(local (in-theory (enable strsubst)))
(defthm stringp-of-strsubst
(stringp (strsubst old new x))
:rule-classes :type-prescription)
(local (assert! (equal (strsubst "World" "Star" "Hello, World!")
"Hello, Star!")))
(local (assert! (equal (strsubst "oo" "aa" "xoooyoo")
"xaaoyaa"))))
(defsection strsubst-list
:parents (substitution)
:short "Carry out a @(see strsubst) replacement throughout a list of strings."
:long "<p>@(call strsubst-list) replaces every occurrence of @('old') with
@('new') throughout @('x'). Here, @('old') and @('new') are strings, but
@('x') is a list of strings. A new list of strings is returned.</p>
<p>Example:</p>
@({
(strsubst-list \"Sun\"
\"Moon\"
'(\"Sun Roof\" \"Hello Sun\" \"Sunny Sunshades\"))
-->
(\"Moon Roof\" \"Hello Moon\" \"Moonny Moonshades\")
})"
;; BOZO consider using defprojection
(defund strsubst-list (old new x)
(declare (xargs :guard (and (stringp old)
(stringp new)
(string-listp x))))
(if (atom x)
nil
(cons (strsubst old new (car x))
(strsubst-list old new (cdr x)))))
(local (in-theory (enable strsubst-list)))
(defthm strsubst-list-when-atom
(implies (atom x)
(equal (strsubst-list old new x)
nil)))
(defthm strsubst-list-of-cons
(equal (strsubst-list old new (cons a x))
(cons (strsubst old new a)
(strsubst-list old new x))))
(defthm string-listp-of-strsubst-list
(string-listp (strsubst-list old new x)))
(local (defthm l0
(equal (strsubst-list old new (list-fix x))
(strsubst-list old new x))))
(defcong list-equiv equal (strsubst-list old new x) 3
:hints(("Goal"
:in-theory (disable l0)
:use ((:instance l0 (x x))
(:instance l0 (x acl2::x-equiv))))))
(defthm strsubst-list-of-append
(equal (strsubst-list old new (append x y))
(append (strsubst-list old new x)
(strsubst-list old new y))))
(defthm strsubst-list-of-revappend
(equal (strsubst-list old new (revappend x y))
(revappend (strsubst-list old new x)
(strsubst-list old new y))))
(defthm strsubst-list-of-rev
(equal (strsubst-list old new (rev x))
(rev (strsubst-list old new x)))))
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