Yes, it's groovy, and it's "?." It's called safe navigation operator
http://groovy.codehaus.org/Operators#Operators-SafeNavigationOperator%28%3F.%29 On Thu, Nov 12, 2009 at 6:03 PM, Laurent PETIT <laurent.pe...@gmail.com> wrote: > 2009/11/3 Alex Osborne <a...@meshy.org>: >> >> Sean Devlin wrote: >>> This is slightly unrealted, but how does one pronounce ->, ->> and the >>> like? Is this documented? >> >> The doc-strings usually give you a nice hint. I usually use "thread" >> for -> and "thread last" for ->>. The actual symbols I think of as >> "arrow" and "double arrow". >> >> Then -?> in contrib is "short-circuiting thread". Not sure about the >> symbol, perhaps "questionable arrow"? ;-) > > The question mark ? is there to "mimic" (somewhat) what one can find > in OO languages such as groovy (I think it's groovy, is it ?) : > > someObject.?propA.?prop2 > > where .? will check if the object is null before trying to get a > property (or method) on it. If null : returns null, if not null, > returns the property etc. > > Initially i wanted to name it ->? but the final ? is by convention > reserved for predicates, so Rich suggested -?> (and also .?. for the > .. equivalent). > > -- > 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 -- Omnem crede diem tibi diluxisse supremum. -- 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
