Learning Functional Programming in Go

Ord algebra

Here're the Ord rules:

Name of rule	Description
Totality	a.lte(b) or b.lte(a)
Anti-symmetry	If a.lte(b) and b.lte(a), then a.equals(b)
Transitivity	If a.lte(b) and b.lte(c), then a.lte(c)
b must be a value of the same Ord as a. If b is not the same Setoid, then the behavior of equals is unspecified (returning false is recommended). The equals variable must return a Boolean (true or false).

 

The values used in the rules are a, b and c. A value which has a Setoid must provide an lte method. The lte method is this algebra's operator and it takes one argument.

From the preceding diagram, we see that an Ord is a Setoid, so the Ord has an Equals operator and the Ord must obey the same rules that a Setoid ...