content.adoc Composition example gets "nth not supported on this type: Long" error

[wrightmikea]

When I evaluate the composition example (using cider nrepl) I get an "nth not supported on this type: Long" error.

user> (require '[lentes.core :as l])
nil
user> (def my-lens (comp l/fst l/fst (l/nth 2)))
#'user/my-lens
user> (def data
[[0 1 2]
[3 4 5]])
#'user/data
user> (l/focus my-lens data)
UnsupportedOperationException nth not supported on this type: Long clojure.lang.RT.nthFrom (RT.java:888)
user>

Either my-lens should have one fewer l/fst function in the composed function or the data needs another level of square brackets, right?

This works for me:

user> (def my-lens2 (comp l/fst (l/nth 2)))
#'user/my-lens2
user> (l/focus my-lens2 data)
2
user> (def data2
[[[0 1 2]
[3 4 5]]])
#'user/data2
user> (l/focus my-lens data2)
2
user>