Per the docs at https://clojure.org/reference/protocols, if more than one protocol extension applies and one is derived from the other then the derived one will be used. In other cases (like two independent interfaces), it is undefined and in my experience you will see different ones get applied between different runs of the JVM. The order the extensions are applied should not affect the first case.
Other options are to use multimethods (which do allow you to express order preferences) or to avoid ambiguous extensions through the use of conditionals either before the call or within the the most generic protocol extension. Alex On Tuesday, March 7, 2017 at 1:14:50 PM UTC-6, Tianxiang Xiong wrote: > > Does `extend-protocol` guarantee order when used with subtypes? > > E.g. suppose class Foo implements interface IFoo. Then, extending both Foo > and IFoo with protocol Bar: > > (extend-protocol Bar > Foo > (do-bar [] > "Foo-bar") > > IFoo > (do-bar [] > "IFoo-bar")) > > Is calling `do-bar` on an object of type Foo guaranteed to give "Foo-bar" > instead of "IFoo-bar"? > > > > -- 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.
