[plt-scheme] Re: behavior of nested quotes in DrScheme/mzscheme

From: Eli Barzilay (eli at barzilay.org)
Date: Fri Dec 1 22:02:27 EST 2006

On Dec  1, Matthias Felleisen wrote:
> On Dec 1, 2006, at 5:12 PM, Michael Vanier wrote:
> > That is helpful -- thanks!  However, it's still not the same as in  
> > mzscheme:
> >
> > > '''''a
> > (list 'quote (list 'quote (list 'quote (list 'quote 'a))))
> >
> > I think this might be even more confusing to a student.
> Are you sure?
> (1) It's 100% correct.
> (2) Students who have used HtDP (properly) are used to the idea of
> seeing data via their (true) constructor rather than some whimsical
> abbreviation convention.
> (3) '(1 2 3) is one of the most confusing things for beginners. I
> am glad you took it out of the language. (Olin Shivers, 2006)

A related anecdote that happened just today was me trying to explain
quasiquote.  In my case I *did* want them to know what happens at the
low level, so I demonstrated the reader effect by evaluating


in MzScheme.  As I was talking about that, I realized how hopelessly
confusing it must be for them -- and these students not beginners.

(It was also very helpful to have the macro stepper today, BTW.)

          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                  http://www.barzilay.org/                 Maze is Life!

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