There is also immutable hash-tables available: http://docs.racket-lang.org/reference/hashtables.html http://docs.racket-lang.org/reference/hashtables.html (Jus

There is also immutable hash-tables available: http://docs.racket-lang.org/reference/hashtables.html http://docs.racket-lang.org/reference/hashtables.html (Just to be clear: there is of course also mutable hash tables available).