[racket] Macros: dealing with optional elements

From: Konrad Hinsen (konrad.hinsen at fastmail.net)
Date: Wed Sep 25 11:00:00 EDT 2013

Laurent writes:

 > Unsyntax-splicing to the rescue!

Great, this evokes memories of Common Lisp macros... More importantly, it works!

J. Ian Johnson writes:

 > This is such a common pattern that there is support for it with a
 > feature called syntax templates, in
 > syntax/parse/experimental/template. You would use (?? super) to add
 > super only if it's given, and nothing otherwise.

Good to see that this is a common pattern. I hope the experiment will prove
satisfactory. For me at least it works fine.

Thanks to both of you,

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