request for a new function, say, `sequence'

[Kenichi Handa <handa@m17n.org>]

In the Indian languages support, we use this kind of
function repeatedly.  But, the function itself is generic
enough to be used in the other cases.  Can I install it in
subr.el (or simple.el)?

(defun sequence (from to type)
  "Return a sequence of type TYPE that contains numbers FROM to TO (inclusive).
TYPE must `list', `vector', or `string'.
If TYPE is `string', all numbers between FROM and TO must be valid
characters."
  (let ((len (1+ (- to from)))
	val)
    (if (>= len 0)
	(cond ((eq type 'list)
	       (while (>= to from)
		 (setq val (cons to val)
		       to (1- to))))
	      ((eq type 'vector)
	       (setq val (make-vector len 0))
	       (while (>= to from)
		 (aset val (- to from) to)
		 (setq to (1- to))))
	      ((eq type 'string)
	       (setq val (make-string len 0))
	       (while (>= to from)
		 (aset val (- to from) to)
		 (setq to (1- to))))
	      (t
	       (error "Invalid type: %s" type))))
    val))

---
Ken'ichi HANDA
handa@m17n.org