Swift Functional Programming - Second Edition

Function currying

Function currying translates a single function with multiple arguments into a series of functions each with one argument. Let's examine an example.

Suppose that we have a function that combines firstName and lastName to return the full name as follows:

func extractFullName(firstName: String, lastName: String) -> String {     return "\(firstName) \(lastName)" } 

This function could be translated into a curried function as follows:

func curriedExtractFullName(firstName: String)(lastName: String) -> String {     return "\(firstName) \(lastName)" } 

As seen from this example, we replace the comma with ) ( parentheses. So now we can use this function as follows:

let fnIncludingFirstName = curriedExtractFullName("John") let extractedFullName ...