[plt-scheme] Evaluating code in namespace of calling module

From: Matthew Flatt (mflatt at cs.utah.edu)
Date: Tue Mar 15 23:27:28 EST 2005

At Mon, 14 Mar 2005 09:22:49 +0100, Erich Rast wrote:
> I'd like to evaluate code by a function or macro that is defined in a 
> module foo, but the code should be evaluated with respect to all of the 
> bindings that are currently active in the module bar that calls the 
> custom evaluation function required from foo. So far, I've tried 
> passing (current-namespace) to the evaluation function and then use 
> parameterize in module foo, but this doesn't seem to work.

Normally, `(current-namespace)' gives you the top-level environment,
outside of any module.

There's no simple way to get a namespace corresponding to the top-level
of the current module. 

You can use `module->namespace' with a specific module name to get a
namespace for the named module. In this case, for example,

> (module bar mzscheme
>    (require foo)
>    (require (lib "class.ss"))
>    (let* ((test% (class* object% ()
>                    (public hello-world)
>                    (define (hello-world)
>                      (display "hello world!")(newline)))))
>      (object? (my-eval 'test% (current-namespace)))
>      )
>    )

I think that `(module->namespace 'bar)' would do what you want.

It's possible to get the name of the enclosing module by using
`syntax-source-module' on a bit of syntax from the module. You'll
likely get back a module-path index, so see `resolve-module-path-index'
from `(lib "moddep.ss" "syntax")'.


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