[racket-dev] A strange problem with namespaces

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Wed May 7 10:27:35 EDT 2014

When I look at this code I can't figure out why (submod "weird.rkt"
evaluator) _isn't_ available at phase 0! Could this be a bug?


On Wed, May 7, 2014 at 9:11 AM, Sam Tobin-Hochstadt
<samth at cs.indiana.edu> wrote:
> This program: https://gist.github.com/samth/e7b55fcef66da9b8416a works
> when line 33 is uncommented, otherwise it gives the error:
> ?: module mismatch;
>  attempted to use a module that is not available
>   possible cause:
>    using (dynamic-require .... #f)
>    but need (dynamic-require .... 0)
>   module: (submod "weird.rkt" evaluator)
>   phase: 0
>   in: phase1-phase0-run
>   context...:
>    weird.rkt: [running body]
> From reading the docs on `dynamic-require`, I can see that
> `(dynamic-require m 'f)` doesn't make anything available for higher
> phases.  However, the actual `dynamic-require` in the program is just
> for a function -- the need for higher phases is an implementation
> detail that's leaking in because it doesn't behave like a regular
> value wrt `dynamic-require`.
> Is there something I can change in the implementation of the internals
> of `f` so that clients of `f` don't need to do the extra
> `(dynamic-require m 0)` in order for `f` to work?
> Sam
> _________________________
>   Racket Developers list:
>   http://lists.racket-lang.org/dev

Posted on the dev mailing list.