[plt-scheme] Expand with stop-list?

From: Jens Axel Søgaard (jensaxel at soegaard.net)
Date: Tue Nov 21 13:48:03 EST 2006

Ryan Culpepper skrev:
> --- Jens Axel Søgaard <jensaxel at soegaard.net> wrote:
>> Is there a version of expand with a stop-list tugged away in
>> a library somewhere?
>> I'd like to use it in the following sitation:
>> The module B implements a "base language".
>> Module A expands to constructs in B.
>> It is now interesting to see what the expansion
>> of A, where syntax from B is not expanded.
>> [...]
> You can see the result in the macro stepper by configuring the macro
> hiding policy to hide only macros from B (or B and mzscheme, or ...).
> See the macro stepper manual at
> http://www.ccs.neu.edu/home/ryanc/macro-stepper/macro-stepper.html
> for more information on configuring the macro stepper's hiding
> policy.

Thanks for the tip.

> There's currently no expand-like procedure that does that. I'll try
> to write one using the macro stepper internals. 

Nice service!

> Like expand-once, it
> will probably not be safe to take the result of this function and
> re-expand or evaluate it.

That's okay, the main use is to check that the translation from
A to B went okay.

Jens Axel Søgaard

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