[plt-scheme] 2htdp/image questions

From: hendrik at topoi.pooq.com (hendrik at topoi.pooq.com)
Date: Fri Apr 23 05:38:38 EDT 2010

On Thu, Apr 22, 2010 at 05:55:35PM -0400, Marco Morazan wrote:
> On Thu, Apr 22, 2010 at 4:50 PM, Stephen Bloch <sbloch at adelphi.edu> wrote:
> >
> > On Apr 22, 2010, at 3:55 PM, Marco Morazan wrote:
> >
> >> May I suggest that this is not a good idea? It breaks the abstraction
> >> that the HtDP languages and universe provide which makes the teaching
> >> of programming to beginners possible. The introduction of something
> >> like cache-image all of the sudden means that not all images are
> >> alike. The _beginner_ must now think about the machinery that renders
> >> images in addition to thinking about the problem/game they are working
> >> on. IMHO, that is not the way to go.
> >
> > What part of "I wouldn't teach this in a beginning course" didn't get through? :-)  The "cache-image" proposal is purely an optimization tool, not to be used until you've got a program that produces correct answers but too slowly.  Most of my beginning students will never write an animation that complex, so they'll never need it.
> >
> Actually, none of it got through clearly. :-( I can only surmise that
> you would only use cache-image for students not in a beginning course
> or you would use it in courses for advanced students. The question
> then is, how many semesters should we expect to keep students using
> universe? If only "advanced" students are to use cache-image, should
> these students not be moved on to a different "more advanced"
> platform?

The *last* thing I'd want to teach them is that functinoal programming
a la Scheme is inherently inefficient and useless for anything but
toy programs.

-- hendrik

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