While your answer is what Manfred is looking for, I still find the original behavior worrying. It lets you expose the internals of opaque data structures without having the relevant inspector. Sam <div class="gmail_quote">On Dec 28, 2013 4:16 PM, "J. Ian Johnson" <<a href="mailto:ianj@ccs.neu.edu">ianj@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> You want to make sure your structs are inspectable. You can define your structs with the #:transparent option or define your own equality relation with the gen:equal+hash generic interface. -Ian ----- Original Message ----- From: Manfred Lotz <<a href="mailto:manfred.lotz@arcor.de">manfred.lotz@arcor.de</a>> To: <a href="mailto:users@racket-lang.org">users@racket-lang.org</a> Sent: Sat, 28 Dec 2013 15:41:28 -0500 (EST) Subject: [racket] hash table confusion I have a hash table (created by using make-hash) where the key is a struct. This seems to work fine although the documentation says The make-hash procedure creates a table where keys are compared with equal?,... and it seems that equal? gives #f if I compare two structs having the same contents: (struct cpd (x y)) (define C1 (cpd 1 "bla")) (define C2 (cpd 1 "bla")) (equal? C1 C2) #f Why does my hash table work fine? In my hash handling I'm using make-hash, hash-ref!, hash-set!, hash-for-each. -- Manfred ____________________ Racket Users list: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> ____________________ Racket Users list: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </blockquote></div>