When records were first introduced there was a little debate over what the behavior of first case should be. If = is defined solely in terms of .equals then two different records with the same key/value mappings must [1] be = to each other to obey the contract of the Map interface even though the values are likely meant to be conceptually distinct. For instance if you had (defrecord Square [length color]) and (defrecord Rope [length color]), then you would have (= (Square. 1 :red) (Rope. 1 :red)) even though a red square is not the same thing as red rope.
To work around the issue, = was changed to be in terms of equiv (see the definitions in [2]). This allows compliance with the Map interface and prevents (= (Square. 1 :red) (Rope. 1 :red)). [1] One idea was to have a hidden key corresponding to the record's type be visible when using the Map interface; that would cause a great deal of complexity and was rejected. [2] https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/Util.java -- 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
