generics.go

package main

import (
	"sort"
	"fmt"
	"constraints"
)

type Vec2[T constraints.Ordered] struct {
	X, Y T
}

func (v Vec2[T]) Add (o Vec2[T]) Vec2[T] {
	return Vec2[T]{
		X: v.X + o.X,
		Y: v.Y + o.Y,
	}
}

func (v Vec2[T]) Eq (o Vec2[T]) bool {
	return v.X == o.X && v.Y == o.Y
}

func Reverse [T any] (s []T) {
    first := 0
    last := len(s) - 1
    for first < last {
        s[first], s[last] = s[last], s[first]
        first++
        last--
    }
}

func Min [T constraints.Ordered] (x, y T) T {
	if x > y {
		return y
	}
	return x
}

func Max [T constraints.Ordered] (x, y T) T {
	if x < y {
		return y
	}
	return x
}

func SliceMin [T constraints.Ordered] (s []T) T {
	r := s[0]
	for _, v := range s[1:] {
		if v < r {
			r = v
		}
	}
	return r
}

func SliceMax [T constraints.Ordered] (s []T) T {
	r := s[0]
	for _, v := range s[1:] {
		if v > r {
			r = v
		}
	}
	return r
}

func Abs [T constraints.Signed] (x T) T {
	if x < 0 {
		return -x
	}
	return x
}

type orderedSlice[T constraints.Ordered] []T

func (s orderedSlice[T]) Len() int           { return len(s) }
func (s orderedSlice[T]) Less(i, j int) bool { return s[i] < s[j] }
func (s orderedSlice[T]) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }

func OrderedSlice[T constraints.Ordered](s []T) {
	sort.Sort(orderedSlice[T](s))
}

func main() {
	var v = Vec2[int]{3, 6}
	var o = Vec2[int]{15, 12}
	fmt.Println(v.Add(o))
	
	data := []int{5,8,1,9,3,5,7,12,5,2,6,8,3}
	OrderedSlice(data)
	fmt.Println(data)
	
	fmt.Println(Abs(1+5))
	fmt.Println(Abs(1-5))
}