[racket] Step function in HTDP intermediate student

From: Yang Zhang (fz15 at msstate.edu)
Date: Sat Aug 21 23:15:51 EDT 2010

Hi, I have a question regarding the step function in DrRacket under
the HTDP intermediate student language. It seems that whenever there
is a local "define-struct" the step function would fail.  Consider a

(define (f x)
  (local ((define-struct a (b c)))

(f 1)

Choose the HTDP intermediate student language, click run, then click
the step button, DrRacket would produce the following message in the
step window:

annotate-inner: nothing expands into begin! : (list 'begin (list
'#%app 'raw 'r) (list '#%app 'check-struct-wraps! 'r) (list '#%app
'raw 'r))

I am using Racket version 5.0.1 (the Ubuntu jaunty i386 download).


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