main.go

package main

import (
	"fmt"
	"iter"
	"slices"
	"strconv"

	"example.org/int/typ"
)

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

func items(push func(typ.Variant) bool) {
	pullInt32, stopInt32 := iter.Pull(integers)
	pullString, stopString := iter.Pull(words)

	defer stopInt32()
	defer stopString()

	for {
		if nextInt32, ok := pullInt32(); ok {
			variant := typ.String(strconv.Itoa(int(nextInt32)))
			if !push(variant) {
				return
			}
		}

		if nextString, ok := pullString(); ok {
			variant := typ.String(nextString)
			if !push(variant) {
				return
			}
		}
	}
}

var integers iter.Seq[int32] = slices.Values([]int32{1, 2, 3_000, 4, 5})
var words iter.Seq[string] = slices.Values([]string{`ورد`, `hat`, `bat`, `cat`, `mat`})

variant.go

package typ

type Variant interface {
	StringValue() *string
	Int32Value() *int32
}

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
}