[racket] top-level-rename

From: Gustavo Massaccesi (gustavo at oma.org.ar)
Date: Tue Aug 12 09:47:47 EDT 2014

+1 . Last year I was experimenting with require-tranformers and
provide-transformers. They are very weird macros, because they have to
be executed in the "wrong order" (from inside to outside, like
functions). They use a newly created syntax-mark, and to break hygiene
you must use syntax-local-require-introduce or
syntax-local-provide-introduce (under the hood, the marker is stored
in a parameter, but the parameter is not exported, so you can't
change/parameterize it).

I think that all of them can be merged in a generalized
syntax-local-introduce with a public parameter. The parameter should
be used only in a parameterize form. Overwriting the parameter doesn't
look like a good idea. I think it will break the current macro and
create a syntax error, but it will not be useful to break the


On Mon, Aug 11, 2014 at 4:22 PM, Alexander D. Knauth
<alexander at knauth.org> wrote:
> On Aug 11, 2014, at 1:44 AM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
>> Answers below, but first a big caution: While these details have been
>> the same for a while, I hope and expect the representation of syntax
>> objects to change in the coming months. I have been threatening to
>> rewrite the macro expander (yes, in Racket) for a while, but things are
>> lining up so that I can actually start trying soon.
> This is off topic, but if your planning on rewriting the macro expander in Racket, would it be possible to make it so that syntax-local-introduce uses a parameter?
> That way for match expanders (etc.) it could set that parameter to a new syntax-introducer so that syntax-local-introduce could be used within match-expanders (etc.)?
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