Re: macros, procedure->macro

[Marius Vollmer]

Dirk Herrmann <address@hidden> writes:

> I have decided for the solution above to avoid having to export an
> additional binding.

I hope that we can avoid exporting bindings that are only used in
macro expansions.  I don't know exactly how (ice-9 syncase) deals with
this right now, but I'd say it is supposed to make the following work:

    (define-module (t1)
      :use-syntax (ice-9 syncase)
      :export-syntax foo)

    (define (bar) #t)

    (define-syntax foo
      (syntax-rules ()
        ((foo)
         (bar))))

    (define-module (t2)
      :use-syntax (ice-9 syncase)
      :use-module (t1))

    (foo)

Note that (t1) doesn't export bar, but the expansion of (foo) uses it.

I have some vague ideas of how to implement this... the basic one is
to add new syntax that allows one to refer to specific bindings from
specific modules, on a very low level.  For example, we could use

    (#:module-ref (t1) bar)

to get at the bar binding of the (t1) module, from anywhere.  Note
that we use a keyword in the operator position.

(ice-9 syncase) could then rewrite references to global variables to
use this form.