Learning Functional Programming in Go

Name monoid

Let's see what we can do with a name. First, we define an interface that has two methods, Append and Zero. We wrap our name in nameContainer.

Our nameContainer is a struct with a single string field, name. Our Append method appends the given name to the long name string it's building up that lives in the magical nameContainer. Our zero morphism for our name string is an empty string.

The content of src/monoid/name_monoid.go would look as follows:

package monoidtype NameMonoid interface {   Append(s string) NameMonoid   Zero() string}func WrapName(s string) NameMonoid {   return nameContainer{name: s}}type nameContainer struct {   name string}func (s nameContainer) Append(name string) NameMonoid {   s.name = s.name + name   return s}func  ...