Example
Clojure functions can be defined with zero or more parameters.
(defn welcome
"Without parameters"
[]
"Hello!")
(defn square
"Take one parameter"
[x]
(* x x))
(defn multiplier
"Two parameters"
[x y]
(* x y))
Arity
The number of arguments a function takes. Functions support arity overloading, which means that functions in Clojure allow for more than one "set" of arguments.
(defn sum-args
;; 3 arguments
([x y z]
(+ x y z))
;; 2 arguments
([x y]
(+ x y))
;; 1 argument
([x]
(+ x 1)))
The arities don't have to do the same job, each arity can do something unrelated:
(defn do-something
;; 2 arguments
([first second]
(str first " " second))
;; 1 argument
([x]
(* x x x)))
