String prepend: Difference between revisions

===A pure function implementation with immutability ===

<lang clojure>

(defn str-prepend [a-string, to-prepend]

(str to-prepend a-string))

</lang>

=== REPL demonstrations with mutability in mind ===

a) with the atom data structure

<lang clojure>

(def s (atom "World"))

(swap! s #(str "Hello, " %))

user=> @s

user=> "Hello, Wolrd"

</lang>

b) with the ref data structure

<lang clojure>

(def s (ref "World"))

user=> "Hello World"

</lang>