The question mark suffix should be used only for predicates. The author of the erroneous prose is currently being forced to drink an extra glass of wine before bed as punishment.
I have *no* idea why I wrote that -- best guess is that is-small? started as a predicate and was later changed for demo reasons. Stuart > Meikel Brandmeyer wrote: >> Hi, >> >> Am 21.07.2009 um 22:48 schrieb Jimmie Houchin: >> >>> (defn is-small? [number] >>> (if (< number 100) "yes" "no" )) >>> >>> Is is-small? a predicate? If so, is this a common pattern for >>> such >>> predicates? >> >> The definition is correct. is-small? is not >> a predicate. It returns a string. So (if (is-small? x) ..) >> is always true! I suspect that the string >> produced by is-small? is used somewhere. >> >> (defn is-small? >> [number] >> (< number 100)) >> >> This would be a predicate since it returns >> a Boolean. >> >> Hope this helps. >> >> Sincerely >> Meikel > > Thanks for the information. > > That is what I thought. Is it proper or idiomatic Clojure to use a "?" > symbol on non-predicate functions? > > That is somewhat what prompted my question. If a "?" symbol is > generally, always or primarily reserved for predicates, it just seemed > strange to use a non-predicate example in the book. Especially when > the > example could just as easily used true or false, instead of yes > or no. > > Thanks again. > > Jimmie > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
