[plt-scheme] PLAI mzscheme and drscheme question

From: Eli Barzilay (eli at barzilay.org)
Date: Wed Apr 6 05:24:38 EDT 2005

On Apr  6, Rohan Nicholls wrote:
> [...]

Not a direct answer but...

The plai collection has combination of the datatype code with the HtDP
language levels, which is not really used.  I suspect that some bad
interaction between these things is what leads to this problem.  If
you're just trying to make your way through the book, then you can try
the code that I've hacked -- it's at


You get a "csu660.ss" to use as a language.  It is a little different
than the plai language -- `define-type's are the same, but `type-case'
should change like this:

  (type-case F1WAE expr
    [num (n) n]
    [add (l r) (+ (interp l fundefs) (interp r fundefs))]
  (cases expr
    [(num n) n]
    [(add l r) (+ (interp l fundefs) (interp r fundefs))]

It should work fine in mzscheme or drscheme (the "CSU660 Class"
language level).

It does have a few issues, which shouldn't be a big problem --

1. Won't work nicely if you want to use modules or compile your code

2. Will make DrScheme check for updates to the plugin.

3. Adds a "Handin" button in DrScheme to submit homeworks, and
   language levels for homeworks.

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

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