Clojure list member cast error

I try to write function thats return true if element exist in list and false if not.

My code:

(defn is_member [elem ilist]
  ((elem []) false)
  (if (= elem (first (list ilist))) 
    (true)
    (is_member elem (rest (list ilist)))
  开发者_开发问答)
)

I try to run it:

(is_member 1 '(1,2,3,4))

But get error:

#<CompilerException java.lang.ClassCastException: java.lang.Integer cannot be cast to clojure.lang.IFn 

What's wrong? How can i fix it?

Thank you.

Looks like you're coming from a language with more extensive pattern-matching than Clojure has; ((elem []) false) is basically nonsense in Clojure. Instead, just test whether ilist is empty.

There are a number of other errors, so here's a snippet that actually works while being as close to what you intended as possible:

(defn is_member [elem ilist]
  (cond (empty? ilist) false
        (= elem (first ilist)) true
        :else (is_member elem (rest ilist))))