source: trunk/j/src/org/armedbear/lisp/chars.lisp @ 1265

;;; chars.lisp
;;;
;;; Copyright (C) 2003 Peter Graves
;;; $Id: chars.lisp,v 1.2 2003-03-14 02:11:21 piso Exp $
;;;
;;; 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

(in-package "COMMON-LISP")

(export '(digit-char-p alphanumericp
          char/= char< char> char<= char>=
          char-not-equal
          char-lessp char-greaterp))


;;; From CMUCL.

(defun digit-char-p (char &optional (radix 10))
  "If char is a digit in the specified radix, returns the fixnum for
  which that digit stands, else returns NIL.  Radix defaults to 10
  (decimal)."
  (declare (character char) (type (integer 2 36) radix))
  (let ((m (- (char-code char) 48)))
    (declare (fixnum m))
    (cond ((<= radix 10)
     ;; Special-case decimal and smaller radices.
     (if (and (>= m 0) (< m radix))  m  nil))
    ;; Digits 0 - 9 are used as is, since radix is larger.
    ((and (>= m 0) (< m 10)) m)
    ;; Check for upper case A - Z.
    ((and (>= (setq m (- m 7)) 10) (< m radix)) m)
    ;; Also check lower case a - z.
    ((and (>= (setq m (- m 32)) 10) (< m radix)) m)
    ;; Else, fail.
    (t nil))))


(defun alphanumericp (char)
  "Given a character-object argument, alphanumericp returns T if the
   argument is either numeric or alphabetic."
  (declare (character char))
  (let ((m (char-code char)))
    (or (< 47 m 58) (< 64 m 91) (< 96 m 123))))


(defun char/= (character &rest more-characters)
  "Returns T if no two of its arguments are the same character."
  (do* ((head character (car list))
  (list more-characters (cdr list)))
       ((atom list) T)
    (unless (do* ((l list (cdr l)))                  ;inner loop returns T
     ((atom l) T)          ; iff head /= rest.
        (if (eq head (car l)) (return nil)))
      (return nil))))


(defun char< (character &rest more-characters)
  "Returns T if its arguments are in strictly increasing alphabetic order."
  (do* ((c character (car list))
  (list more-characters (cdr list)))
       ((atom list) T)
    (unless (< (char-int c)
         (char-int (car list)))
      (return nil))))


(defun char> (character &rest more-characters)
  "Returns T if its arguments are in strictly decreasing alphabetic order."
  (do* ((c character (car list))
  (list more-characters (cdr list)))
       ((atom list) T)
    (unless (> (char-int c)
         (char-int (car list)))
      (return nil))))


(defun char<= (character &rest more-characters)
  "Returns T if its arguments are in strictly non-decreasing alphabetic order."
  (do* ((c character (car list))
  (list more-characters (cdr list)))
       ((atom list) T)
    (unless (<= (char-int c)
    (char-int (car list)))
      (return nil))))


(defun char>= (character &rest more-characters)
  "Returns T if its arguments are in strictly non-increasing alphabetic order."
  (do* ((c character (car list))
  (list more-characters (cdr list)))
       ((atom list) T)
    (unless (>= (char-int c)
    (char-int (car list)))
      (return nil))))


(defmacro equal-char-code (character)
  `(let ((ch (char-code ,character)))
     (if (< 96 ch 123) (- ch 32) ch)))


(defun char-not-equal (character &rest more-characters)
  "Returns T if no two of its arguments are the same character.
   Font, bits, and case are ignored."
  (do* ((head character (car list))
  (list more-characters (cdr list)))
       ((atom list) T)
    (unless (do* ((l list (cdr l)))
     ((atom l) T)
        (if (= (equal-char-code head)
         (equal-char-code (car l)))
      (return nil)))
      (return nil))))


(defun char-lessp (character &rest more-characters)
  "Returns T if its arguments are in strictly increasing alphabetic order.
   Font, bits, and case are ignored."
  (do* ((c character (car list))
  (list more-characters (cdr list)))
       ((atom list) T)
    (unless (< (equal-char-code c)
         (equal-char-code (car list)))
      (return nil))))


(defun char-greaterp (character &rest more-characters)
  "Returns T if its arguments are in strictly decreasing alphabetic order.
   Font, bits, and case are ignored."
  (do* ((c character (car list))
  (list more-characters (cdr list)))
       ((atom list) T)
    (unless (> (equal-char-code c)
         (equal-char-code (car list)))
      (return nil))))