ClassCastException when calling Clojure function

Question

I have written the following bit of code

(defn create [title url]
  (when (not-any? clojure.string/blank? '(title url))
    (println "doing stuff")))

However when I call the function

(create "title" "url")

I get the following error and cannot figure out what I am doing wrong

ClassCastException clojure.lang.Symbol cannot be cast to java.lang.CharSequence  clojure.string/blank? (string.clj:279)

If i change '(title url) to (sequence [title url]) it works so clearly I am misunderstanding what the quote does. Can someone explain or perhaps propose a better way (if it exists)? — James Hughes
– James Hughes, Commented Jul 13, 2013 at 19:59

matt_h · Accepted Answer · 2013-07-13 20:17:09Z

3

This is one of the things that also tripped me up when I first started learning clojure. Basically, you should use

(list title url)

The clojure compiler treats

'(title url)

as

(quote (title url))

'quote' does not evaluate anything inside of it, so 'title' and 'url' are just symbols (clojure.lang.Symbols to be precise).

answered Jul 13, 2013 at 20:17

matt_h

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