[plt-scheme] plai: lazyness and exercise 6.4.2

From: Aleix Conchillo Flaqué (aconchillo at gmail.com)
Date: Wed Aug 26 09:17:46 EDT 2009

On Wed, Aug 26, 2009 at 03:36, Shriram Krishnamurthi<sk at cs.brown.edu> wrote:
> You have at least a partial understanding of what is going on, which
> is a start.  However, you haven't stated a concrete question.  What
> precisely is the problem you're trying to solve (in your own words),
> and how far do you think you've gotten?  Do you think you have a
> solution that is correct but too complex, or one that is correct but
> only partial, or no solution at all?

OK, I think I finally get it, correct me if wrong. With eager regime
we need to store FAE-Value types in the repository, which are, in
fact, the possible outputs of our evaluation, so interpreting before
storing in the repository is what we need. With lazy evaluation we
store FAE expressions in the repository directly leaving the
evaluation until needed (until lookup).

The origin of my problem was that I used DefrdSub defined in 6.4.
There, it should use FAE-Value (which is not yet explained). Now, I've
seen that the code of the interpreter is correct at the end of the
chapter. I always try to do it by myself, so I had to fight a bit
until everything made sense, but that helps understanding things much



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