Warning: you switched from a teaching language to full Racket. The former would have caught this mistake, which is why we designed them for HtDP. Racket is for grown-up parenthesis eaters -- who want the behavior of cond that you just experienced, or so I am told. -- Matthias
On Aug 5, 2014, at 4:25 PM, Daniel Bastos <dbas...@toledo.com> wrote: > On Tue, Aug 5, 2014 at 5:06 PM, Jens Axel Søgaard <jensa...@soegaard.net> > wrote: > What happens in create-bst-word, when the word to inserted is the same > as (node-word bst) ? > > Aha! I see. It returns void because there is no case for when the string is > equal. > > > (void? (create-bst-word (create-bst-word false "dan") "dan")) > #t > > I patched it with an else-case now. > > (define (create-bst-word bst str) > (cond > ((false? bst) > (make-node str false false)) > ((string<? str (node-word bst)) ;; insert at the left > (make-node (node-word bst) > (create-bst-word (node-left bst) str) > (node-right bst))) > ((string>? str (node-word bst)) ;; insert at the right > (make-node (node-word bst) > (node-left bst) > (create-bst-word (node-right bst) str))) > (else (make-node (node-word bst) > (node-left bst) > (node-right bst))))) > > > (void? (create-bst-word (create-bst-word false "dan") "dan")) > #f > > Thank you. > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
