Learning Functional Programming in Go

In FP, contracts don't lie

Let's look an example of some imperative code:

type Dividend struct {   Val int}func (n Dividend) Divide(divisor int) int {   return n.Val/divisor}func main() {   d := Dividend{2}   fmt.Printf("%d", d.Divide(0))}

What is our contract in the preceding code?

The contract is our method's signature: func (n Dividend) Divide(divisor int) int

What three questions must our contract answer?

1. What does our contract expect? 

• Answer: It expects the following: 
  • The Dividend.Val to be populated with an int
  • The divisor to be an int

2. What does our contract guarantee? 

• Answer: It promises to return an integer

3. What does the contract maintain? 

• Answer: Not applicable in this simple case

What happens when we run the preceding ...