+;;;; character functions
+;;;;
+;;;; This implementation assumes the use of ASCII codes and the
+;;;; specific character formats used in SBCL (and its ancestor, CMU
+;;;; CL). It is optimized for performance rather than for portability
+;;;; and elegance, and may have to be rewritten if the character
+;;;; representation is changed.
+;;;;
+;;;; KLUDGE: As of sbcl-0.6.11.25, at least, the ASCII-dependence is
+;;;; not confined to this file. E.g. there are DEFTRANSFORMs in
+;;;; srctran.lisp for CHAR-UPCASE, CHAR-EQUAL, and CHAR-DOWNCASE, and
+;;;; they assume ASCII. -- WHN 2001-03-25
+
+;;;; This software is part of the SBCL system. See the README file for
+;;;; more information.
+;;;;
+;;;; This software is derived from the CMU CL system, which was
+;;;; written at Carnegie Mellon University and released into the
+;;;; public domain. The software is in the public domain and is
+;;;; provided with absolutely no warranty. See the COPYING and CREDITS
+;;;; files for more information.
+
+(in-package "SB!IMPL")
+
+;;; We compile some trivial character operations via inline expansion.
+#!-sb-fluid
+(declaim (inline standard-char-p graphic-char-p alpha-char-p
+ upper-case-p lower-case-p both-case-p alphanumericp
+ char-int))
+(declaim (maybe-inline digit-char-p digit-weight))
+
+(deftype char-code ()
+ `(integer 0 (,char-code-limit)))
+
+(macrolet ((frob (char-names-list)
+ (collect ((results))
+ (dolist (code char-names-list)
+ (destructuring-bind (ccode names) code
+ (dolist (name names)
+ (results (cons name (code-char ccode))))))
+ `(defparameter *char-name-alist* ',(results)
+ #!+sb-doc
+ "This is the alist of (character-name . character) for characters with
+ long names. The first name in this list for a given character is used
+ on typeout and is the preferred form for input."))))
+ (frob ((#x00 ("Null" "^@" "Nul"))
+ (#x01 ("^a" "Soh"))
+ (#x02 ("^b" "Stx"))
+ (#x03 ("^c" "Etx"))
+ (#x04 ("^d" "Eot"))
+ (#x05 ("^e" "Enq"))
+ (#x06 ("^f" "Ack"))
+ (#x07 ("Bell" "^g" "Bel"))
+ (#x08 ("Backspace" "^h" "Bs"))
+ (#x09 ("Tab" "^i" "Ht"))
+ (#x0A ("Newline" "Linefeed" "^j" "Lf" "Nl" ))
+ (#x0B ("Vt" "^k"))
+ (#x0C ("Page" "^l" "Form" "Formfeed" "Ff" "Np"))
+ (#x0D ("Return" "^m" "Cr"))
+ (#x0E ("^n" "So"))
+ (#x0F ("^o" "Si"))
+ (#x10 ("^p" "Dle"))
+ (#x11 ("^q" "Dc1"))
+ (#x12 ("^r" "Dc2"))
+ (#x13 ("^s" "Dc3"))
+ (#x14 ("^t" "Dc4"))
+ (#x15 ("^u" "Nak"))
+ (#x16 ("^v" "Syn"))
+ (#x17 ("^w" "Etb"))
+ (#x18 ("^x" "Can"))
+ (#x19 ("^y" "Em"))
+ (#x1A ("^z" "Sub"))
+ (#x1B ("Escape" "^[" "Altmode" "Esc" "Alt"))
+ (#x1C ("^\\" "Fs"))
+ (#x1D ("^]" "Gs"))
+ (#x1E ("^^" "Rs"))
+ (#x1F ("^_" "Us"))
+ (#x20 ("Space" "Sp"))
+ (#x7f ("Rubout" "Delete" "Del")))))
+\f
+;;;; accessor functions
+
+(defun char-code (char)
+ #!+sb-doc
+ "Returns the integer code of CHAR."
+ (etypecase char
+ (base-char (char-code (truly-the base-char char)))))
+
+(defun char-int (char)
+ #!+sb-doc
+ "Returns the integer code of CHAR. This is the same as char-code, as
+ CMU Common Lisp does not implement character bits or fonts."
+ (char-code char))
+
+(defun code-char (code)
+ #!+sb-doc
+ "Returns the character with the code CODE."
+ (declare (type char-code code))
+ (code-char code))
+
+(defun character (object)
+ #!+sb-doc
+ "Coerces its argument into a character object if possible. Accepts
+ characters, strings and symbols of length 1."
+ (flet ((do-error (control args)
+ (error 'simple-type-error
+ :datum object
+ ;;?? how to express "symbol with name of length 1"?
+ :expected-type '(or character (string 1))
+ :format-control control
+ :format-arguments args)))
+ (typecase object
+ (character object)
+ (string (if (= 1 (length (the string object)))
+ (char object 0)
+ (do-error
+ "String is not of length one: ~S" (list object))))
+ (symbol (if (= 1 (length (symbol-name object)))
+ (schar (symbol-name object) 0)
+ (do-error
+ "Symbol name is not of length one: ~S" (list object))))
+ (t (do-error "~S cannot be coerced to a character." (list object))))))
+
+(defun char-name (char)
+ #!+sb-doc
+ "Given a character object, char-name returns the name for that
+ object (a symbol)."
+ (car (rassoc char *char-name-alist*)))
+
+(defun name-char (name)
+ #!+sb-doc
+ "Given an argument acceptable to string, name-char returns a character
+ object whose name is that symbol, if one exists. Otherwise, () is returned."
+ (cdr (assoc (string name) *char-name-alist* :test #'string-equal)))
+\f
+;;;; predicates
+
+(defun standard-char-p (char)
+ #!+sb-doc
+ "The argument must be a character object. Standard-char-p returns T if the
+ argument is a standard character -- one of the 95 ASCII printing characters
+ or <return>."
+ (declare (character char))
+ (and (typep char 'base-char)
+ (let ((n (char-code (the base-char char))))
+ (or (< 31 n 127)
+ (= n 10)))))
+
+(defun %standard-char-p (thing)
+ #!+sb-doc
+ "Return T if and only if THING is a standard-char. Differs from
+ standard-char-p in that THING doesn't have to be a character."
+ (and (characterp thing) (standard-char-p thing)))
+
+(defun graphic-char-p (char)
+ #!+sb-doc
+ "The argument must be a character object. Graphic-char-p returns T if the
+ argument is a printing character (space through ~ in ASCII), otherwise
+ returns ()."
+ (declare (character char))
+ (and (typep char 'base-char)
+ (< 31
+ (char-code (the base-char char))
+ 127)))
+
+(defun alpha-char-p (char)
+ #!+sb-doc
+ "The argument must be a character object. Alpha-char-p returns T if the
+ argument is an alphabetic character, A-Z or a-z; otherwise ()."
+ (declare (character char))
+ (let ((m (char-code char)))
+ (or (< 64 m 91) (< 96 m 123))))
+
+(defun upper-case-p (char)
+ #!+sb-doc
+ "The argument must be a character object; upper-case-p returns T if the
+ argument is an upper-case character, () otherwise."
+ (declare (character char))
+ (< 64
+ (char-code char)
+ 91))
+
+(defun lower-case-p (char)
+ #!+sb-doc
+ "The argument must be a character object; lower-case-p returns T if the
+ argument is a lower-case character, () otherwise."
+ (declare (character char))
+ (< 96
+ (char-code char)
+ 123))
+
+(defun both-case-p (char)
+ #!+sb-doc
+ "The argument must be a character object. Both-case-p returns T if the
+ argument is an alphabetic character and if the character exists in
+ both upper and lower case. For ASCII, this is the same as Alpha-char-p."
+ (declare (character char))
+ (let ((m (char-code char)))
+ (or (< 64 m 91) (< 96 m 123))))
+
+(defun digit-char-p (char &optional (radix 10.))
+ #!+sb-doc
+ "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)
+ #!+sb-doc
+ "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)
+ #!+sb-doc
+ "Returns T if all of its arguments are the same character."
+ (do ((clist more-characters (cdr clist)))
+ ((atom clist) T)
+ (unless (eq (car clist) character) (return nil))))
+
+(defun char/= (character &rest more-characters)
+ #!+sb-doc
+ "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)
+ #!+sb-doc
+ "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)
+ #!+sb-doc
+ "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)
+ #!+sb-doc
+ "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)
+ #!+sb-doc
+ "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))))
+
+;;; Equal-Char-Code is used by the following functions as a version of char-int
+;;; which loses font, bits, and case info.
+
+(defmacro equal-char-code (character)
+ `(let ((ch (char-code ,character)))
+ (if (< 96 ch 123) (- ch 32) ch)))
+
+(defun char-equal (character &rest more-characters)
+ #!+sb-doc
+ "Returns T if all of its arguments are the same character.
+ Font, bits, and case are ignored."
+ (do ((clist more-characters (cdr clist)))
+ ((atom clist) T)
+ (unless (= (equal-char-code (car clist))
+ (equal-char-code character))
+ (return nil))))
+
+(defun char-not-equal (character &rest more-characters)
+ #!+sb-doc
+ "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)
+ #!+sb-doc
+ "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)
+ #!+sb-doc
+ "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))))
+
+(defun char-not-greaterp (character &rest more-characters)
+ #!+sb-doc
+ "Returns T if its arguments are in strictly non-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))))
+
+(defun char-not-lessp (character &rest more-characters)
+ #!+sb-doc
+ "Returns T if its arguments are in strictly non-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))))
+\f
+;;;; miscellaneous functions
+
+(defun char-upcase (char)
+ #!+sb-doc
+ "Returns CHAR converted to upper-case if that is possible."
+ (declare (character char))
+ (if (lower-case-p char)
+ (code-char (- (char-code char) 32))
+ char))
+
+(defun char-downcase (char)
+ #!+sb-doc
+ "Returns CHAR converted to lower-case if that is possible."
+ (declare (character char))
+ (if (upper-case-p char)
+ (code-char (+ (char-code char) 32))
+ char))
+
+(defun digit-char (weight &optional (radix 10))
+ #!+sb-doc
+ "All arguments must be integers. Returns a character object that
+ represents a digit of the given weight in the specified radix. Returns
+ NIL if no such character exists. The character will have the specified
+ font attributes."
+ (declare (type (integer 2 36) radix) (type unsigned-byte weight))
+ (and (typep weight 'fixnum)
+ (>= weight 0) (< weight radix) (< weight 36)
+ (code-char (if (< weight 10) (+ 48 weight) (+ 55 weight)))))