One little nit that confuses me. Boolean/FALSE is documented as being of type Boolean in Java documentation, yet it is treated by Clojure the same as primitive boolean false:
user=> (clojure-version) "1.3.0" user=> (if Boolean/FALSE "logical true" "logical false") "logical false" user=> (identical? Boolean/FALSE false) true Does anyone know why? Thanks, Andy On Fri, Apr 13, 2012 at 11:41 AM, Sean Corfield <seancorfi...@gmail.com>wrote: > On Fri, Apr 13, 2012 at 3:33 AM, Vinzent <ru.vinz...@gmail.com> wrote: > > Just like Boolean's javadoc puts a strong > > emphasis on the fact that public Boolean(boolean value) constructor > usually > > shouldn't be used, clojure's docstring should say that (= x false) may > give > > you a result which will confuse you, so you'd better use 'false?' > instead. > > (def f (Boolean. false)) > (false? f) > ;; => false > (true? f) > ;; => false > (= f false) > ;; => true > (if f :t :f) > ;; => :t > > So 'false?' doesn't help you here. > > No one should be using (Boolean. false) in Clojure code - we have true > / false. Why create a Java object whose documentation says not to do > it? > > So if anyone runs into this problem _in real world code_ it's because > they are calling a Java API that somehow returns a Java Boolean object > embedded in the result. If you are working with a Java data structure > full of _Objects_ then you need to take care of converting those > Object instances into appropriate Clojure values. Calling (boolean v) > is sufficient to convert the Java Object to a Clojure true/false > value. > -- > Sean A Corfield -- (904) 302-SEAN > An Architect's View -- http://corfield.org/ > World Singles, LLC. -- http://worldsingles.com/ > > "Perfection is the enemy of the good." > -- Gustave Flaubert, French realist novelist (1821-1880) > > -- > 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 > -- 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
