[plt-scheme] macro keyword conflicting with other imports?

Matthew writes:
>
>>     (syntax-rules (fun)
>>       ...
> The `fun' literal above matches identifiers with the same binding for
> `fun' as the context of the literal.
> 
Wow, this is a more refined sense of matching than
I ever suspected.  Neat!  (Um, I think.)
Now I understand why cond's `=>' only works when `=>' hasn't been rebound.


Matthias writes:
> 
> Export fun as a keyword that blows up when used in an improper context. 
> 
Not sure if this is what you meant, but:
I made `fun' a syntax-id-rules with no clauses, so it always blows up,
except when it occurs inside the intended macro which preemptively
transforms it away.
But this way I'm able to export `fun', so that other people trying to
multiply-import the keyword will get a plausible error message.
...Still, seems like an awfully odd contortion!

It's clear to me, I don't fully understand this Hygiene thing;
Am off to look up the Dybvig paper referenced in help-desk...

Thanks for the help,
--ian