map with fn - anonymous function
work in progress, sorry
(map (fn [arg] (+ arg 5)) [1 2 3 4 5])
There is a syntactic short-cut for the anonymous function that does not require a name for the arguments
#(+ %1 5)
Adding this into our previous expression we can see that its still quite readable and helps keep the code clean.
(map #(+ arg 5) [1 2 3 4 5])
Anonymous function name
Anonymous functions do not have an externally referable name, so must be used in-line with an expression.
The fn function can be defined with a name, however, this is only available in the scope of that function definition, the name cannot be used to refer to that function outside of its definition.
Including a name within a fn definition enables the function to call itself, therefore creating an anonymous recursive function.