Functions

In Clojure, a function call is simply a list whose first element resolves to a function. For example, this call to str concatenates its arguments to create a string:

 ​(str "hello" " " "world")​
 ​-> "hello world"​

Function names are typically hyphenated, as in clear-agent-errors. If a function is a predicate, then by convention its name should end with a question mark. As an example, the following predicates test the type of their argument, and all end with a question mark:

 ​(string? "hello")​
 ​-> true​
 ​​
 ​(keyword? :hello)​
 ​-> true​
 ​​
 ​(symbol? 'hello)​
 ​-> true​

To define your own functions, use defn:

 ​(​defn​ ​name​ doc-string? attr-map? [params*] body)​

The attr-map associates metadata with the function’s var. It’s covered ...

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