Function: eshell-hist-parse-event-designator

eshell-hist-parse-event-designator is a byte-compiled function defined in em-hist.el.gz.

Signature

(eshell-hist-parse-event-designator REFERENCE)

Documentation

Parse a history event designator beginning in REFERENCE.

Source Code

;; Defined in /usr/src/emacs/lisp/eshell/em-hist.el.gz
(defun eshell-hist-parse-event-designator (reference)
  "Parse a history event designator beginning in REFERENCE."
  (let* ((index (string-match eshell-hist-event-designator reference))
	 (end (and index (match-end 0))))
    (unless index
      (error "Invalid history event designator `%s'" reference))
    (let* ((event (match-string 1 reference))
	   (pos
	    (cond
	     ((string= event "!") (ring-length eshell-history-ring))
	     ((string= event "#") (error "!# not yet implemented"))
	     ((string-match "^-?[0-9]+$" event)
	      (let ((num (string-to-number event)))
		(if (>= num 0)
		    (- (ring-length eshell-history-ring) num)
		  (1- (abs num)))))
	     ((string-match "^\\(\\??\\)\\([^?]+\\)\\??$" event)
	      (let ((pref (if (> (length (match-string 1 event)) 0)
			      "" "^"))
		    (str (match-string 2 event)))
		(save-match-data
		  (eshell-previous-matching-input-string-position
		   (concat pref (regexp-quote str)) 1))))
	     (t
	      (error "Failed to parse event designator `%s'" event)))))
      (and pos (cons pos end)))))