Learning Functional Programming in Go

The src/server/server_options.go file

We'll use the Go standard library errors package because we simply want to create an error object:

package serverimport (   . "utils"   "errors")

We define a ServerOption type to simplify our function signatures:

type ServerOption func(*options) error

Currying allows functions to yield new functions as their return value. Is that what MaxNumber is doing? MaxNumber is a function and returns a ServerOption. A SeverOption is a function. So, yes. We have some currying going on here.

Our first ServerOption function is MaxNumber. It has a simple responsibility: assigning the value of its argument (n) to our option's maxNumber field:

func MaxNumber(n int) ServerOption {   return func(o *options) error { o.maxNumber ...