;;; -*- Mode: Scheme -*-
(define (ed-def . args)
  "(ed-def &optional NAME KEEP? USE-EXISTING?)"
  (letrec ((y-or-n
	    (lambda (prompt)
	      (let ((ans (readline (string-append prompt " [y/N]"))))
		(or (equal? ans "y")
		    (equal? ans "Y"))))))
    (let* ((name (or (and (> (length args) 0) (car args))
		     (let ((nm (readline "File Name: ")))
		       (if (string-null? nm)
			   (tmpnam)
			   (begin
			     (add-history nm)
			     nm)))))
	   (keep? (or (and (> (length args) 1) (cadr args))
		      (y-or-n "Keep file when done?")))
	   (use? (and (file-exists? name)
		      (or (and (> (length args) 2) (caddr args))
			  (y-or-n "Use existing file?"))))
	   (p '())
	   (ed (or (getenv "XEDITOR")
		   (getenv "EDITOR")
		   (getenv "VISUAL")
		   (and (file-exists? "/usr/bin/editor")
			"editor")
		   (and (or (file-exists? "/bin/vi")
			    (file-exists? "/usr/bin/vi"))
			"vi")
		   (error "None of XEDITOR, EDITOR, nor VISUAL are set."))))
      (and (not use?)
	   (set! p (open-file name "w"))
	   (display ";;; -*- scheme -*-\n" p)
	   (close-port p))
      (system (string-append "$EDITOR " name))
      (load name)
      (if (not keep?)
	  (system (string-append "rm -f " name)))
      #t)))