Step by Step solution about How to resolve the algorithm Catamorphism step by step in the Go programming language

The provided Go code demonstrates the use of a higher-order function reduce that takes a reduction function (rf) and a list of integers (m) as input and returns a single integer as the result of applying the reduction function to each element of the list.

• Main Function:

  • The main function initializes a slice of integers n with values [1,2,3,4,5].
  • It calls the reduce function three times, each time passing a different reduction function:
    • add: Sums the elements of the list.
    • sub: Subtracts the elements of the list.
    • mul: Multiplies the elements of the list.
  • The results of each reduction are printed to the console.

• Reduction Functions:

  • add, sub, and mul are simple reduction functions that perform addition, subtraction, and multiplication, respectively.

• reduce Function:

  • The reduce function is a higher-order function that takes a reduction function and a list of integers as input.
  • It initializes r with the first element of the list m[0].
  • It iterates through the remaining elements of the list m[1:] and applies the reduction function rf to the current result r and the current element v.
  • The updated result is stored in r.
  • Finally, the function returns the reduced result r.

• Example Output:

  15
  -9
  120
  

package main

import (
	"fmt"
)

func main() {
	n := []int{1, 2, 3, 4, 5}

	fmt.Println(reduce(add, n))
	fmt.Println(reduce(sub, n))
	fmt.Println(reduce(mul, n))
}

func add(a int, b int) int { return a + b }
func sub(a int, b int) int { return a - b }
func mul(a int, b int) int { return a * b }

func reduce(rf func(int, int) int, m []int) int {
	r := m[0]
	for _, v := range m[1:] {
		r = rf(r, v)
	}
	return r
}