[MIT-Scheme-devel] Request feedback on design of dired commands

[Richard Loveland]

I've written a couple of simple dired commands to help me transition to
an ``all-Edwin'' lifestyle -- I'd love to get some feedback on them from
this list:

* DIRED-DO-SHELL-COMMAND

* DIRED-RUN-PROGRAM-IN-BACKGROUND (not sure about this name,
  suggestions welcome)

The code is below, along with questions.

The first command is pretty straightforward. I don't like that it uses
the UNIXism "&", though. I'd like to rewrite this in something portable
to Windows, et al. There could just be a conditional that checks if
Scheme is running on a non-UNIX system, but I'd be happy to use a more
robust cross-platform idiom if y'all can recommend one.

(define-command dired-do-shell-command
  "Run a shell command on the file or directory at point.
Note that this is a synchronous operation; Edwin will not accept 
input until the shell command finishes."
  (lambda ()
    (list ((environment-lookup
            (->environment '(edwin process)) 'shell-command-prompt)
           "Shell command on file: ")
          (command-argument)))
  (lambda (command pathname)
    (run-shell-command
     (string-append command " "
                    (->namestring (dired-current-pathname)) " " "&"))))

The second, DIRED-RUN-PROGRAM-IN-BACKGROUND, was written because Edwin
was blocking on the call to RUN-SHELL-COMMAND in the above, even with
the appended "&".

It'd be cool to unify the two if there's a better way to get all this
functionality into one command.

(define-command dired-run-program-in-background
  "Run a program on the file or directory at point.
This starts the program as a background subprocess, so you can
continue using Edwin."
  (lambda ()
    (let ((shell-command-prompt
           (environment-lookup
            (->environment '(edwin process)) 'shell-command-prompt)))
      (list 
       (shell-command-prompt "With arguments: ")
       (shell-command-prompt "Run program on file: ")
       (command-argument))))
  (lambda (user-args program-name pathname)
    (let* ((program (os/find-program program-name (user-homedir-pathname) 
(ref-variable exec-path))) ; modify in .edwin as needed
           (filename (->namestring (dired-current-pathname)))
           (arguments (list->vector (list user-args filename))))
      (start-subprocess-in-background program arguments #f))))

(define-key 'dired #\! 'dired-do-shell-command)
(define-key 'dired #\& 'dired-run-program-in-background)