Learning Functional Programming in Go

First-class functions

First-class functions allow us to make new functions by providing our base functions with function parameters. In the following code, our base function is Filter. By passing ByMake("Toyota") to Filter, we remove most of the car items from our collection, leaving only Toyota:

cars := Filter(ByMake("Toyota"))

We also have the ability to transform any function that works on single elements into a function that works on lists, by wrapping it with the Map function. Without our new functional style of programming, we might be tempted to implement a for loop and apply the fmt.Sprintf transformation on each individual car, as follows:

// cars: Honda Accord, Honda Accord ES2, Lexus IS250, Honda CR-V, Lexus SC 430,...for _, car ...