[plt-scheme] Another macro venture

On Sat, 2006-09-09 at 14:57 -0400, Eli Barzilay wrote:
> The exercise that Jens offered is generally the way to tackle macro
> problems (that's actually the case for all macro systems).  What I

Of course, how else?

> claim is that you will find that there is no solution that is
> portable, since to do this you need some reflection mechanism (some
> reification of the [global] environment).  Bill's solution uses
> Scheme's canonical reflective device, but that suffers (again) from
> the illnesses of the toplevel.  (And I think that `eval' is one
> standard feature that can be difficult to deal with if you want
> portable behavior.)

Curiosity question: given that quasi-quote and define-syntax are R5RS,
what sort of portability issues can arise among R5RS implementations?

Also, what are these "illnesses of the toplevel" (pointers to good
discussions will suffice)?

 -- Bill Wood