[racket] style: nested cond (fine!)

From: Stephen Bloch (bloch at adelphi.edu)
Date: Tue Feb 21 12:01:33 EST 2012

On Feb 21, 2012, at 11:45 AM, Matthias Felleisen wrote:

> How can they do that [read and modify code written by bad OO programmers] if we teach them only bad OO programming? 

I wouldn't suggest that, of course.  The last time I taught CS2 (or rather CS1 in Java, having been expressly forbidden to use any other language), I had students build lists and trees with polymorphism, then do it again with nulls.

I also had them build a list-of-lista data structure from scratch with a functional API, and use this to solve the "permutations" problem; then I had them do the same problem again using Java's built-in collection classes (which have a very stateful API).  The results were enlightening: almost everybody got it working the functional way, but when we did it using Java collection classes, ONE student in the class turned in a solution that FREQUENTLY (not always) produced correct answers.

Stephen Bloch
sbloch at adelphi.edu

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