In practice, that's done. For instance, in common lisp there are procedures like `MAKE-ARRAY` and `MAKE-HASH-TABLE`. The interesting thing is that these hash t

In practice, that's done. For instance, in common lisp there are procedures like `MAKE-ARRAY` and `MAKE-HASH-TABLE`. The interesting thing is that these hash tables and arrays are considered to be atomic. Clojure generalizes the notion of pairs, which in some ways is more elegant (a collection of items being atomic isn't necessarily intuitive) and in some ways is less (now your language has to describe how this abstraction operates).