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|
; 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/
;
; 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: Jared Davis <jared@centtech.com>
; Additional author: David Rager <ragerdl@cs.utexas.edu>
(in-package "STR")
(include-book "cat")
(include-book "ieqv")
(local (include-book "std/lists/repeat" :dir :system))
(local (include-book "std/lists/take" :dir :system))
(local (include-book "arithmetic"))
(defsection pad-trim
:parents (std/strings)
:short "Functions for trimming whitespace and padding with spaces.")
(defsection rpadchars
:parents (pad-trim)
:short "Pad a character-list with spaces on the right."
:long "<p>@(call rpadchars) extends the character list @('x') to length
@('len') by adding spaces on the right. For instance,</p>
@({
(rpadchars '(#\\f #\\o #\\o) 5)
-->
'(#\\f #\\o #\\o #\\Space #\\Space)
})
<p>This is completely dumb: we don't try to account for newlines, tabs, or
anything like that, and just add @('#\\Space') characters until reaching the
desired width.</p>
<p>If no new spaces are needed, @('x') is returned unchanged and no consing is
performed.</p>"
(defund rpadchars (x len)
(declare (xargs :guard (and (character-listp x)
(natp len)))
(type integer len))
(mbe :logic
(append (make-character-list x)
(repeat (nfix (- (nfix len) (len x))) #\Space))
:exec
(let* ((x-len (length (the list x)))
(diff (- len x-len)))
(if (> diff 0)
(append x (repeat diff #\Space))
x))))
(local (in-theory (enable rpadchars)))
(defthm character-listp-of-rpadchars
(character-listp (rpadchars x len)))
(defthm len-of-rpadchars
(equal (len (rpadchars x len))
(max (len x) (nfix len))))
(defcong charlisteqv equal (rpadchars x len) 1)
(defcong icharlisteqv icharlisteqv (rpadchars x len) 1))
(defsection rpadstr
:parents (pad-trim)
:short "Pad a string with spaces on the right."
:long "<p>@(call rpadstr) extends the string @('x') to length @('len') by
adding spaces on the right. For instance,</p>
@({
(rpadchars \"foo\" 5)
-->
\"foo \"
})
<p>This is completely dumb: we don't try to account for newlines, tabs, or
anything like that, and just add @('#\\Space') characters until reaching the
desired width.</p>
<p>If no new spaces are needed, @('x') is returned unchanged and no consing or
coercion is performed.</p>"
(local (in-theory (enable rpadchars append-chars)))
(defund rpadstr (x len)
(declare (xargs :guard (and (stringp x)
(natp len)))
(type string x)
(type integer len))
(mbe :logic
(implode (rpadchars (explode x) len))
:exec
(let* ((x-len (length (the string x)))
(diff (- len x-len)))
(if (> diff 0)
(let ((spaces (repeat diff #\Space)))
(implode (mbe :logic (append-chars x spaces)
:exec (if (zp x-len)
spaces
(append-chars-aux x (- x-len 1) spaces)))))
x))))
(local (in-theory (enable rpadstr)))
(defthm stringp-of-rpadstr
(stringp (rpadstr x len))
:rule-classes :type-prescription)
(defthm len-of-explode-of-rpadstr
(implies (force (stringp x))
(equal (len (explode (rpadstr x len)))
(max (length x)
(nfix len)))))
(defcong streqv equal (rpadstr x len) 1)
(defcong istreqv istreqv (rpadstr x len) 1))
(defsection lpadchars
:parents (pad-trim)
:short "Pad a character-list with spaces on the left."
:long "<p>@(call lpadchars) extends the character list @('x') to length
@('len') by adding spaces on the left. For instance,</p>
@({
(lpadchars '(#\\f #\\o #\\o) 5)
-->
'(#\\Space #\\Space #\\f #\\o #\\o)
})
<p>This is completely dumb: we don't try to account for newlines, tabs, or
anything like that, and just add @('#\\Space') characters until reaching the
desired width.</p>
<p>If no new spaces are needed, @('x') is returned unchanged and no consing is
performed.</p>"
(defund lpadchars (x len)
(declare (xargs :guard (and (character-listp x)
(natp len)))
(type integer len))
(mbe :logic
(append (repeat (nfix (- (nfix len) (len x))) #\Space)
(make-character-list x))
:exec
(let* ((x-len (length x))
(diff (- len x-len)))
(if (< 0 diff)
(make-list-ac diff #\Space x)
x))))
(local (in-theory (enable lpadchars)))
(defthm character-listp-of-lpadchars
(character-listp (lpadchars x len)))
(defthm len-of-lpadchars
(equal (len (lpadchars x len))
(max (len x) (nfix len))))
(defcong charlisteqv equal (lpadchars x len) 1)
(defcong icharlisteqv icharlisteqv (lpadchars x len) 1))
(defsection lpadstr
:parents (pad-trim)
:short "Pad a string with spaces on the left."
:long "<p>@(call lpadstr) extends the string @('x') to length @('len') by
adding spaces on the left. For instance,</p>
@({
(lpadstr \"foo\" 5)
-->
\" foo\"
})
<p>This is completely dumb: we don't try to account for newlines, tabs, or
anything like that, and just add @('#\\Space') characters until reaching the
desired width.</p>
<p>If no new spaces are needed, @('x') is returned unchanged and no consing is
performed.</p>"
(local (in-theory (enable lpadchars)))
(defund lpadstr (x len)
(declare (xargs :guard (and (stringp x)
(natp len)))
(type string x)
(type integer len))
(mbe :logic
(implode (lpadchars (explode x) len))
:exec
(let* ((x-len (length x))
(diff (- len x-len)))
(if (< 0 diff)
(implode (make-list-ac diff #\Space (explode x)))
x))))
(local (in-theory (enable lpadstr)))
(defthm stringp-of-lpadstr
(stringp (lpadstr x len))
:rule-classes :type-prescription)
(defthm len-of-explode-of-lpadstr
(implies (force (stringp x))
(equal (len (explode (lpadstr x len)))
(max (length x)
(nfix len)))))
(defcong streqv equal (lpadstr x len) 1)
(defcong istreqv istreqv (lpadstr x len) 1))
(defsection trim-bag
:parents (pad-trim)
:short "Remove particular characters from the front and end of a string."
:long "<p>@(call trim-bag) removes the characters in @('bag') from the
front and end of the string @('x').</p>
<p>BOZO eventually make this efficient.</p>"
(defund trim-aux (x bag)
(declare (xargs :guard (and (character-listp x)
(character-listp bag))))
;; Remove all whitespace characters from the front of a list.
(if (consp x)
(if (acl2::member (car x) bag) ; :test eql is default
(trim-aux (cdr x) bag)
x)
nil))
(local (in-theory (enable trim-aux)))
(defthm character-listp-of-trim-aux
(implies (force (character-listp x))
(character-listp (trim-aux x bag))))
(local (defthm true-listp-when-character-listp
(implies (character-listp x)
(true-listp x))))
(defund trim-bag (x bag)
(declare (xargs :guard (and (stringp x)
(character-listp bag))))
(let* ((chars (explode x))
(chars (trim-aux chars bag)) ;; eat spaces at the front
(chars (reverse chars)) ;; flip so we can get to the back
(chars (trim-aux chars bag)) ;; eat spaces at the back
(chars (reverse chars))) ;; flip again so it's back to normal
(implode chars)))
(local (in-theory (enable trim-bag)))
(defthm stringp-of-trim-bag
(stringp (trim-bag x bag))
:rule-classes :type-prescription))
(defsection trim
:parents (pad-trim)
:short "Remove whitespace characters from the front and end of a string."
:long "<p>@(call trim) removes whitespace characters from the
front and end of the string @('x').</p>"
(defund trim (x)
(declare (xargs :guard (stringp x)))
(let* ((bag (list #\Space
#\Tab
#\Newline
#\Page
(code-char 13) ;; Carriage Return
(code-char 11)))) ;; Vertical Tab
(trim-bag x bag)))
(local (in-theory (enable trim)))
(defthm stringp-of-trim
(stringp (trim x))
:rule-classes :type-prescription))
|
