Learning Functional Programming in Go

A semigroup is a missing neutral value

If we are missing the unit/zero/neutral value, then we don’t have a monoid, we have a semigroup. Note that a semigroup can be converted into a monoid.

That was a very interesting discussion of the algebra of monoids, but what the heck are they good for, and why should we care?

Here are a couple of good uses for monoids.