;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001
;;        David J. Biesack

;; This file is not part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; Edit shell command.  Look up COMMAND in $PATH
;; and edit the file
;;
;; Sort of like doing
;;     # emacsclient `whence command`
;; from ksh, or
;;     % emacsclient `which command`
;; from csh
;;
;; Author: David Biesack (David.Biesack@sas.com  or biesack@mindspring.com)
;; Last Modified By: biesack@mindspring.com
;; Last Modified: Thu Mar 15 17:41:54 2001

(defun ef (command)
  "Edit function/command"
  (interactive "sEdit shell command: ")
  (let ((command-path (sh-which command)))
    (if  command-path
         (find-file command-path)
         (error "Command %s not found in path." command))))

(defun delimited-string-to-list (string &optional separator)
  "Parse a STRING into a list. Elements are delimited by SEPARATOR,
which defaults to \" \""
  (or separator (setq separator " "))
  (let (list
        index)
    (while (> (length string) 0)
      (setq index (string-match separator string))
      (if index
          (setq list (cons (substring string 0 index) list)
                string (substring string (1+ index)))
          (setq list (cons string list)
                string "")))
    (nreverse list)))

(defvar pathext (if (getenv "PATHEXT")
		    (delimited-string-to-list (getenv "PATHEXT") ";")
		  ())
  "executable extensions.")

(defvar search-path (delimited-string-to-list (getenv "PATH")
					      (cond ((eq system-type 'windows-nt)
						     ";")
						    (t ":")))
  "Environment list PATH as a list")

(defun sh-which (command)
  "Return pathname where COMMAND is found in $PATH"
  (let (path
        file
        attr
        found
	candidate
	(extensions (cons "" pathext)))
    (while (and extensions (not found))
      (setq candidate (concat command (car extensions))
	    extensions (cdr extensions))
      (setq path search-path)
      (while (and path (not found))
	(and (file-exists-p (setq file (concat (car path) "/" candidate)))
	     (setq attr (file-attributes file))
	     (not (eq t (nth 0 attr)))	; not directory
					; (or (message (format "%s %s" file attr)) (sit-for 1) t)
	     (string-match "x" (nth 8 attr))
	     (setq found file))
	(setq path (cdr path)))
      )
    found))