- ((null ch) (return-from potential-number))
- ((digit-char-p ch))
- ((char= ch #\.))
- ((char= ch #\+) (next))
- ((char= ch #\-) (next))
- (t (return-from potential-number)))
- (when ch
- (while (and ch (digit-char-p ch)) (next))
- (when (null ch)
- (return-from potential-number t)))
- (when (char= ch #\.)
- (next)
- (when ch
- (while (and ch (digit-char-p ch)) (next))))
- (when (or (char= ch #\E) (char= ch #\e)
- (char= ch #\D) (char= ch #\d)
- (char= ch #\F) (char= ch #\f)
- (char= ch #\L) (char= ch #\l))
- (next)
- (cond
- ((null ch) (return-from potential-number))
- ((digit-char-p ch))
- ((char= ch #\+) (next))
- ((char= ch #\-) (next))
- (t (return-from potential-number)))
- (unless (and ch (digit-char-p ch))
- (return-from potential-number))
- (while (and ch (digit-char-p ch)) (next)))
- (null ch))))
-
-(defun special-escape (s package)
- (return-from special-escape s)
- (if (or (potential-number s)
- (special-symbol-name s :uppercase (not (eq package (find-package "JS")))))
+ ;; Digits TODO: DIGIT-CHAR-P should work with the current
+ ;; radix here. If the radix is not decimal, then we have to
+ ;; make sure there is not a decimal-point in the string.
+ ((digit-char-p char))
+ ;; Signs, ratios, decimal point and extension mark
+ ((find char "+-/._^"))
+ ;; Number marker
+ ((alpha-char-p char)
+ (when (and (< i (1- (length string)))
+ (alpha-char-p (char string (1+ i))))
+ ;; fail: adjacent letters are not number marker, or
+ ;; there is a decimal point in the string.
+ (return-from potential-number-p)))
+ (t
+ ;; fail: there is a non-allowed character
+ (return-from potential-number-p)))))
+ (and
+ ;; Second Rule. In particular string is not empty.
+ (find-if #'digit-char-p string)
+ ;; Third rule
+ (let ((first (char string 0)))
+ (and (not (char= first #\:))
+ (or (digit-char-p first)
+ (find first "+-._^"))))
+ ;; Fourth rule
+ (not (find (char string (1- (length string))) "+-)"))))
+
+#+nil
+(mapcar #'potential-number-p
+ '("1b5000" "777777q" "1.7J" "-3/4+6.7J" "12/25/83" "27^19"
+ "3^4/5" "6//7" "3.1.2.6" "^-43^" "3.141_592_653_589_793_238_4"
+ "-3.7+2.6i-6.17j+19.6k"))
+
+#+nil
+(mapcar #'potential-number-p '("/" "/5" "+" "1+" "1-" "foo+" "ab.cd" "_" "^" "^/-"))
+
+(defun escape-token-p (string &optional uppercase)
+ (or (potential-number-p string)
+ (escape-symbol-name-p string uppercase)))
+
+;;; Returns the token in a form that can be used for reading it back.
+(defun escape-token (s &optional uppercase)
+ (if (escape-token-p s uppercase)