<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 21 Feb 2011, at 1:33:46, Stephen Bloch wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>On Feb 21, 2011, at 8:04 AM, Kathryn Gray <<a href="mailto:kathryn.gray@cl.cam.ac.uk">kathryn.gray@cl.cam.ac.uk</a>> wrote:<br><br><blockquote type="cite">I've added a preliminary version of define-wish to the teaching languages and the test-engine but it doesn't presently do everything that was discussed/requested in the original conversation. And I don't know how to extend it to support those features.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">So can someone with more experience in developing functions for the teaching languages assist?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">(define-wish n) presently provides the programmer with a function, n, of arity one (that raises an exception about wishes when called). I would like this function to be of variable arity, but I have not determined how to do this.<br></blockquote><br>Yes: ideally one would write<br>(define-wish (f x y z))<br>and it would define a 3-parameter function named f, whose arity would be enforced by Check Syntax and which would raise an appropriate exception when called.<br></div></blockquote><div><br></div><div>The options at present (and after discussion with Matthias) are for</div><div><br></div><div>(define-wish name)</div><div><br></div><div>and</div><div><br></div><div>(define-wish name default-value)</div><div><br></div><div>So that the wish definitions are lightweight. The arity concern goes away completely with (define-wish (name parameter1 parameter2...))</div><div><br></div><div>-Kathy</div><br><blockquote type="cite"><div><br><blockquote type="cite"><br></blockquote><blockquote type="cite">I would also like the test-engine to be able to report every wished for function, whether or not it's called.<br></blockquote><br>Good point.<br><br>One of these days I've GOT to sit down and learn to write macros....<br><br><br><br>Stephen Bloch<br><a href="mailto:sbloch@adelphi.edu">sbloch@adelphi.edu</a></div></blockquote></div><div><br> </div> <br></body></html>