slots.clj

user=> (. (clojure.lang.Box. 5) :val)
5
user=> (defrecord Foo [seq])
user.Foo
user=> (def r (Foo. 5))
#'user/r
user=> (:seq r)
5
user=> (.seq r)
([:seq 5])
user=> (. r seq)
([:seq 5])
user=> (. r :seq)
([:seq 5])

a) (. r :seq) is not a documented feature
b) it only works with known type,not via reflection as in this call