By design, true? never throws an exception. Neither does false? You can create functions similar to those that throw an exception when given a non-boolean value, if you want such functions.
(Note: examples below rely on existence of clojure.core/boolean? which does not exist in Clojure 1.8.0) user=> (clojure-version) "1.9.0-alpha19" user=> (defn true-boolean? #_=> [x] #_=> (assert (boolean? x)) #_=> (true? x)) #'user/true-boolean? user=> (true-boolean? true) true user=> (true-boolean? false) false user=> (true-boolean? identity) AssertionError Assert failed: (boolean? x) user/true-boolean? (form-init3633819970128261150.clj:3) Do the following function return values help shed any light on things, perhaps? They demonstrate that true and false are boolean value, but identity has a value that is not a boolean type, but a function type. user=> (boolean? true) true user=> (boolean? false) true user=> (boolean? identity) false user=> (fn? true) false user=> (fn? false) false user=> (fn? identity) true Andy On Fri, Sep 1, 2017 at 9:06 PM, Rostislav Svoboda < rostislav.svob...@gmail.com> wrote: > > identity isn't a boolean, so neither true? nor false? should return true > for it > > But then why it should return 'false'? > > 2017-09-02 6:04 GMT+02:00 Justin Smith <noisesm...@gmail.com>: > > identity isn't a boolean, so neither true? nor false? should return true > for > > it > > > > > > On Fri, Sep 1, 2017 at 9:01 PM Rostislav Svoboda > > <rostislav.svob...@gmail.com> wrote: > >> > >> > (true? identity) -> false > >> > (false? identity) -> false > >> > (= false false) -> true > >> > >> Well: > >> (= identity identity) -> true > >> > >> My math books say booleans can't be true and false in the same time. > >> > >> -- > >> 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 unsubscribe from this group and stop receiving emails from it, send > an > >> email to clojure+unsubscr...@googlegroups.com. > >> For more options, visit https://groups.google.com/d/optout. > > > > -- > > 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 unsubscribe from this group and stop receiving emails from it, send an > > email to clojure+unsubscr...@googlegroups.com. > > For more options, visit https://groups.google.com/d/optout. > > -- > 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 unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- 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 unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
