Learning Functional Programming in Go

Color blocks functor

A functor consists of a structure, usually a slice in Go, and a transformation operation, that is, the mapping function:

Structure	Eight blocks, each filled with a different color
Transformation operation	f(x) = x - 30, where x is the hue

 

Below, is a functor that maps eight colored blocks to eight corresponding blocks whose color has been altered by applying the transformation operations above to adjust the hue of the color displayed in the boxes.

The preceding diagram shows a single f(x) arrow to keep the clutter to a minimum, but a more accurate representation would show arrows from each original element ...