;;
;;  Some functions which will be used
;;  in initialization of EMACS
;;

(defun iterate-on-list (list action)
  (when list
    (let ((dir (car list)))
      (let ((val (funcall action dir)))
	(if val val
	  (iterate-on-list (cdr list)
			   action))))))

(defun which (prog)
  (let ((app (executable-find prog)))
    (if app 
	(file-truename app)
      (iterate-on-list (split-string (getenv "PATH") ":")
		       #'(lambda (dir)
			   (let ((filename (concat dir "/" prog)))
			     (if (file-executable-p filename)
				 filename
			       nil)))))))

(defun partition-list (lis separator-p sublis acc)
  (if (null lis)
      (if (null sublis)
	  acc
	(append acc (list sublis)))
    (let ((item (car lis)))
      (if (funcall separator-p item)
	  (partition-list (cdr lis) separator-p ()
			  (if (null sublis)
			      acc
			    (append acc (list sublis))))
	(partition-list (cdr lis) separator-p
			(append sublis (list item))
			acc)))))

(defun nth-op (n op arg)
  (if (= n 0)
      arg
    (nth-op (- n 1) op (funcall op arg))))

(defun compose (f g &rest args)
  (apply f (apply g args)))

(defun my-reduce (acc lis op)
  (cond ((and (not (null acc))
	      (not (null lis)))
	 (cons (funcall op (car acc) (car lis))
	       (my-reduce (cdr acc) (cdr lis) op)))
	((null lis) acc)
	((null acc) lis)
	(t nil)))

(defun merge-xlist (lis op acc)
  (if (null lis)
      acc
    (merge-xlist (cdr lis) op
		 (my-reduce acc (car lis) op))))


(defun sudo-shell-command (command)
  (let ((proc (start-process-shell-command 
	       "*sudo*"
	       "*sudo*"
	       (concat "sudo bash -c "
		       (shell-quote-argument command)))))
    (process-send-string proc 
			 (read-passwd "Your Password:"))
    (process-send-string proc "\r")
    (process-send-eof proc)))

(defun find-file-by-search-dir (dir name)
  (let ((find-cmd (concat "find "
			  dir
			  " -name \""
			  name "\""
			  " -print | head -n 1")))
    (let ((data (shell-command-to-string find-cmd)))
      (if (> (length data) 0)
	  (substring data 0 -1)
	nil))))

(defun my-fold-left (op acc lst)
  (if lst
      (my-fold-left op (funcall op acc (car lst))
		    (cdr lst))
    acc))

(defun my-replace-string (s old new)
  (replace-regexp-in-string (regexp-quote old)
			    new s t t))

(defun my-zap-multiple-empty-lines ()
  (while (re-search-forward "^\\([ ]*\n?\\)*\n")
	(replace-match "\n")))

(defun first-n-elem (list n action)
  (if (or (= n 0)
		  (not list))
	  nil
	(let ((ele (car list))
		  (rem (cdr list)))
	  (if (funcall action ele)
		  (cons ele (first-n-elem rem (- n 1) action))
		(first-n-elem rem n action)))))
;; define key bindings
;;