[plt-scheme] The filename of the file in the definition window

Ah, of course.

Thanks,
Robby

On Dec 20, 2007 7:51 AM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> At Wed, 19 Dec 2007 16:39:32 -0600, "Robby Findler" wrote:
> > On Dec 19, 2007 4:15 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> > > Avoid creating pipes, because it creates too much work for you in
> > > managing a concurrent copy operation and closing the pipe at the right
> > > time. Instead, parameterize the call to `system' to set
> > > `current-input-port' to your port.
>
> I was reacting in part to this thread:
>
>  http://list.cs.brown.edu/pipermail/plt-scheme/2007-December/021727.html
>
>
> > I would have thought that something like
> >
> >   (thread (lambda () (copy-port  ...) (close-*-port ..)))
> >
> > would have been all you'd need.
>
> Plus the `thread-wait's, which you have. You're relatively good at
> this. :)
>
> Also, it would be a good idea to wait until the process is done. If the
> process explicitly closes its stdout and stderr before existing, and if
> you create processes in a loop, it's possible (though unlikely) that
> you'd create processes faster than they terminate.
>
>
> Still, I think it's too much work in the sense that `system' will do
> all of that for you, and it will do it more efficiently in some cases
> (like this one, where the port is a file port). Just write
>
>  (define (run-wc-on-file filename)
>    (call-with-input-file filename
>      (λ (file-port)
>        (parameterize ([current-input-port file-port])
>          (system wc)))))
>
> The first three lines are as in your code, the last two lines replace
> another 16.
>
> Matthew
>
>