Clojure has that. Clojure is built on abstractions. Most operations in clojure source code convert to calls to java interfaces. For example, a simple function

Clojure has that. Clojure is built on abstractions. Most operations in clojure source code convert to calls to java interfaces. For example, a simple function call (map foo bar) compiles to a call to .invoke() method on map, a java object that implements clojure.lang.IFn. Similarly, all of clojure's datastructure operations boil down to calls to objects implementing the java interfaces clojure.lang.IPersistentCollection, c.l.IPersistentMap, c.l.IPersistentSet, etc. To add a new datastructure, simply create a new class that implements the appropriate interfaces, and you'll get literal syntax support. To answer your question, Clojure records are named classes that implement IPersistentMap so they're a drop-in replacement for "normal" maps, that also implement an additional interface so the compiler can generate java field lookups to access items without the cost of a hash lookup. For example (defn foo [map] (println (:a map))) (defrecord MyObj [a]) (foo {:a 1}) (foo (MyObj. 1)) Both calls work exactly the same, except the MyObj doesn't have hash lookups for the fields defined in the class.