<div>I taught from HtDP/2e last semester, using 2htdp/image, and had similar experiences with my students playing with overlay/xy. I must admit it wasn't what I expected after using overlay, and I agree with Don. With the caveat that I'm not concerned about backward compatibility, I would prefer to see overlay/xy updated to be consistent with overlay, in the way Don described. Short of this possibility, a revision to the documentation would also be helpful... :-)</div>
<div><br></div><div>Thanks to Don for articulating this behavior so well, and to Robby for soliciting further opinions!</div><div><br>Marc</div><div><br></div><br>
<div><div>On Sun, Jan 30, 2011 at 10:33 PM, <<a href="mailto:users-request@racket-lang.org">users-request@racket-lang.org</a>> wrote:</div></div><div><br></div><div><div>Message: 4</div><div>Date: Sun, 30 Jan 2011 21:04:52 -0600</div>
<div>From: Robby Findler <<a href="mailto:robby@eecs.northwestern.edu" target="_blank">robby@eecs.northwestern.edu</a>></div><div>To: Don Blaheta <<a href="mailto:dblaheta@monm.edu" target="_blank">dblaheta@monm.edu</a>></div>
<div>Cc: "<a href="mailto:users@racket-lang.org" target="_blank">users@racket-lang.org</a>" <<a href="mailto:users@racket-lang.org" target="_blank">users@racket-lang.org</a>></div><div>Subject: Re: [racket] overlay and overlay/xy</div>
<div>
Message-ID:</div><div> <AANLkTinGAs=<a href="mailto:xM7GQyjj%2Bq5BLmHMCjMiC_8TNxHn31xJD@mail.gmail.com" target="_blank">xM7GQyjj+q5BLmHMCjMiC_8TNxHn31xJD@mail.gmail.com</a>></div><div>Content-Type: text/plain; charset=UTF-8</div>
<div><br></div><div>I find this to be a compelling argument but I am worried about</div><div>backwards compatibilty for others.</div><div><br></div><div>The least I can do is a better job documenting this (and thanks to</div>
<div>your message I think I'll be able to do that) but I'm not sure about</div><div>changing the semantics.</div><div><br></div><div>Do others that may depend on 2htdp/image have an opinion?</div><div><br></div><div>
Robby</div></div><div><br></div><div><br></div><div><br></div><div><br></div>