[plt-scheme] A couple of macro questions

From: Chongkai Zhu (czhu at cs.utah.edu)
Date: Tue Nov 24 10:46:18 EST 2009

Todd O'Bryan wrote:
> I just started working through Dybvig's _The Scheme Programming
> Language_ (which I found by re-reading previous posts that were
> answers to "How do I learn Scheme?" Don't know how I missed it the
> first several times it was suggested, but the explanation of macros
> and stuff has been very nice.) and have a couple of questions.
> 1. I tried for a long time to define let* using only a single pattern,
> but couldn't. Using two patterns was pretty easy. I don't want to put
> my code up here since it's an exercise, but am I right that you need a
> 0-assignment pattern and a 1-or-more-assignment pattern for the
> ellipses to work correctly?

Does recursion always need a base case, and a recursive case?


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