diff options
Diffstat (limited to 'lisp/emacs-lisp/cl-extra.el')
| -rw-r--r-- | lisp/emacs-lisp/cl-extra.el | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/lisp/emacs-lisp/cl-extra.el b/lisp/emacs-lisp/cl-extra.el index 3761d04c2c2..c8404e0bc2d 100644 --- a/lisp/emacs-lisp/cl-extra.el +++ b/lisp/emacs-lisp/cl-extra.el @@ -383,6 +383,41 @@ With two arguments, return rounding and remainder of their quotient." "Return 1 if X is positive, -1 if negative, 0 if zero." (cond ((> x 0) 1) ((< x 0) -1) (t 0))) +;;;###autoload +(cl-defun cl-parse-integer (string &key start end radix junk-allowed) + "Parse integer from the substring of STRING from START to END. +STRING may be surrounded by whitespace chars (chars with syntax ` '). +Other non-digit chars are considered junk. +RADIX is an integer between 2 and 36, the default is 10. Signal +an error if the substring between START and END cannot be parsed +as an integer unless JUNK-ALLOWED is non-nil." + (cl-check-type string string) + (let* ((start (or start 0)) + (len (length string)) + (end (or end len)) + (radix (or radix 10))) + (or (<= start end len) + (error "Bad interval: [%d, %d)" start end)) + (cl-flet ((skip-whitespace () + (while (and (< start end) + (= 32 (char-syntax (aref string start)))) + (setq start (1+ start))))) + (skip-whitespace) + (let ((sign (cl-case (and (< start end) (aref string start)) + (?+ (cl-incf start) +1) + (?- (cl-incf start) -1) + (t +1))) + digit sum) + (while (and (< start end) + (setq digit (cl-digit-char-p (aref string start) radix))) + (setq sum (+ (* (or sum 0) radix) digit) + start (1+ start))) + (skip-whitespace) + (cond ((and junk-allowed (null sum)) sum) + (junk-allowed (* sign sum)) + ((/= start end) (error "Not an integer string: %s" string)) + (t (* sign sum))))))) + ;; Random numbers. |