main.go

package main

import (
	"fmt"
	"unsafe"
)

func main() {
	fmt.Println("Sizeof(Variant{}) =", unsafe.Sizeof(Variant{}), "bytes")
	for item := range items {
		if item.StringValue() != nil {
			fmt.Println("Found a string value:", *item.StringValue())
		}
	}
}

func items(push func(Variant) bool) {
	push(Int32(1))
	push(String("hat"))
	push(String("bat"))
	push(Int32(3000))
}

type Variant struct {
	stringValue *string
	int32Value  *int32
}

func String(value string) Variant {
	return Variant{stringValue: &value}
}

func Int32(value int32) Variant {
	return Variant{int32Value: &value}
}

func (t Variant) StringValue() *string {
	return t.stringValue
}

func (t Variant) Int32Value() *int32 {
	return t.int32Value
}