Question

I’m a Clojure newbie. I’m trying to understand why the second form doesn’t work:

First form:

user=>(def nums(range 3))
(0 1 2)
user=>(map #(list %1) nums)
((0) (1) (2))

Second form:

user=> (map #(list %1) (0 1 2))
java.lang.ClassCastException: java.lang.Integer cannot be cast to clojure.lang.IFn 
(NO_SOURCE_FILE:0)

Answer 1

The problem is the expression (0 1 2), which is interpreted as 0 applied to 1 and 2; that’s impossible because 0 isn’t a function.

(map #(list %1) '(0 1 2))

works as intended, though.