rename-in issue

[Lucas Liendo]

Hi everyone! I've a very dumb question (as still not very experienced
Racket programmer), I'm doing the following:

(require net/url
web-server/dispatchers/filesystem-map
(rename-in web-server/dispatchers/dispatch-files
(make dispatch-files))
(rename-in web-server/dispatchers/dispatch-sequencer
(make dispatch-sequencer)))

As you can see `make` is defined both in
`web-server/dispatchers/dispatch-files` and
`web-server/dispatchers/dispatch-sequencer` and I think that's the
reason for this error:

/tmp/rename-example.rkt:7:20: module: identifier already required
at: interface-version
in: web-server/dispatchers/dispatch-sequencer
location...:
/tmp/rename-example.rkt:7:20

Traceback continues but I think that's enough. So is there a
workaround to this? I'd really like to do a rename instead of using
`prefix-in`. Shouldn't this error not happen as it defeats `rename-in`
purpose at all?

--
Cheers,
Lucas.

[Sorawee Porncharoenwase]

There are two colliding names. make and interface-version. As shown in the error message, you fixed one but not the other.

(require net/url
         web-server/dispatchers/filesystem-map
         web-server/dispatchers/dispatch-files
         (rename-in web-server/dispatchers/dispatch-sequencer
                    [make make*]
                    [interface-version interface-version*]))

works for me.

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[Jens Axel Søgaard]

Den tor. 9. apr. 2020 kl. 11.04 skrev Lucas Liendo <liendo...@gmail.com>:

Hi everyone! I've a very dumb question (as still not very experienced
Racket programmer), I'm doing the following:

(require net/url
         web-server/dispatchers/filesystem-map
         (rename-in web-server/dispatchers/dispatch-files
                    (make dispatch-files))
         (rename-in web-server/dispatchers/dispatch-sequencer
                    (make dispatch-sequencer)))

As you can see `make` is defined both in
`web-server/dispatchers/dispatch-files` and
`web-server/dispatchers/dispatch-sequencer` and I think that's the
reason for this error:

/tmp/rename-example.rkt:7:20: module: identifier already required
  at: interface-version

This shows that interface-version is the (new) cultprit.
You can rename it to avoid a collision - or if you don't need it, you can 
simply omit it:

    #lang racket

    (require net/url
         web-server/dispatchers/filesystem-map
         (rename-in web-server/dispatchers/dispatch-files
                    (make dispatch-files))

         (except-in (rename-in web-server/dispatchers/dispatch-sequencer
                               (make dispatch-sequencer))
                    interface-version))


/Jens Axel
https://racket-stories.com

[Bogdan Popa]

I'd recommend using `prefix-in' with the dispatcher modules, as that
avoids these types of issues altogether:

(require (prefix-in files: web-server/dispatchers/dispatch-files)
(prefix-in sequencer: web-server/dispatchers/dispatch-sequencer))

(sequencer:make
(files:make ...)
...)

[Lucas Liendo]

Thanks all for the suggestions and for pointing out that
`interface-version` was the conflict, I didn't carefully read the
message and assumed `make` was the culprit!

--
Cheers,
Lucas.

Radar : http://radar-monitoring.readthedocs.org/en/latest/index.html