Learning Functional Programming in Go

The (g.f)(x) = g(f(x)) implementation

Now let's take a peek at the code.

Here are the f and g functions from the preceding diagram:

package composefunc Humanize(b bool) string {   if b { return "yes" } else { return "no" }}func Emphasize(s string) string {   return s + "!!"}func EmphasizeHumanize(b bool) string {   return Emphasize(Humanize(b))}

Now for the new stuff.

We'll create two types. Fbs represents f (or A to B), which takes a bool (true), and returns a string, "yes". Fss represents g (or B to C). Fss takes a string, "yes", and returns a string, "yes!!":

type Fbs func(bool) stringtype Fss func(string) string

Here's our Compose function:

func Compose(g Fss, f Fbs) Fbs {   return func(x bool) string {      return g(f(x))   }}

Nested inside our Compose ...