<div class="gmail_quote">On Thu, Jan 6, 2011 at 1:06 AM, Matthias Felleisen <<a href="mailto:matthias@ccs.neu.edu">matthias@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> Start reading HtDP/2e @ <a href="http://www.ccs.neu.edu/home/matthias/HtDP2e/" target="_blank">http://www.ccs.neu.edu/home/matthias/HtDP2e/</a> It uses strings, which may be more familiar to you and which accommodate a bit more variety. Then switch back to HtDP/1e. <div><div></div><div class="h5"> On Jan 5, 2011, at 7:18 AM, Sayth Renshaw wrote: > > Can someone expand on the syntax for symbols? I can develop the check-guess game simply without symbols but cannot with symbols. > Trying many versions of the symbol syntax but with no success. > > This the example for symbols, but how can I test conditions with a symbol? > (define (reply s) > (cond > [(symbol=? s 'GoodMorning) 'Hi] > > [( > symbol=? s 'HowAreYou?) 'Fine] > > [( > symbol=? s 'GoodAfternoon) 'INeedANap] > > [( > symbol=? s 'GoodEvening) 'BoyAmITired])) > > ;function check-guess > ;given number evaluate to one of three answers > ;number -> number -> string > > tested without symbols and got it working so was trying to emulate this with symbols > > (define (check-guess guess target) > (cond > [(< guess target) "Too Small"] > [(= guess target) "Perfect"] > [(> guess target) "Too large"] > > > > ;(define (check-guess guess target) > ; (cond > ; [(symbol=? 'guess (< guess target) 'Too small)] > ; [(symbol=? 'guess (= guess target) 'Perfect)] > ; [(symbol=? 'guess (> guess target) 'Too Large)])) > > ;(define (check-guess guess target) > ; (cond > ; [(symbol=? (< guess target) 'True 'Too Small)] > ; [(symbol=? (= guess target) 'True 'Perfect)] > ; [(symbol=? (> guess target) 'True 'Too Large)])) > > ;(define (check-guess guess target) > ; (= s( < guess target)) > ; (= s( = guess target)) > ; (= s( > guess target)) > ; (cond > ; [(symbol= s 'true 'Too Small)] > ; [(symbol= s 'true 'Perfect)] > ; [(symbol= s 'true 'Too Large)])) > > ;(define (check-guess guess target) > ; [(symbol=? guess (< target guess) "Too small")] > > </div></div><div><div></div><div class="h5">> _________________________________________________ > For list-related administrative tasks: > <a href="http://lists.racket-lang.org/listinfo/users" target="_blank">http://lists.racket-lang.org/listinfo/users</a> </div></div></blockquote></div> Thanks getting some coffee into a checking it out now. Thanks for the tips.