github.com/nevalang/neva@v0.23.1-0.20240507185603-7696a9bb8dda/internal/runtime/funcs/range.go

package funcs

import (
	"context"

	"github.com/nevalang/neva/internal/runtime"
)

type streamIntRange struct{}

func (streamIntRange) Create(
	io runtime.FuncIO,
	_ runtime.Msg,
) (func(ctx context.Context), error) {
	fromIn, err := io.In.Port("from")
	if err != nil {
		return nil, err
	}

	toIn, err := io.In.Port("to")
	if err != nil {
		return nil, err
	}

	dataOut, err := io.Out.Port("data")
	if err != nil {
		return nil, err
	}

	return func(ctx context.Context) {
		var fromMsg, toMsg runtime.Msg

		for {
			select {
			case <-ctx.Done():
				return
			case fromMsg = <-fromIn:
			}

			select {
			case <-ctx.Done():
				return
			case toMsg = <-toIn:
			}

			var (
				idx  int64 = 0
				last bool  = false
				data int64 = fromMsg.Int()
			)

			for !last {
				if data == toMsg.Int()-1 {
					last = true
				}

				item := streamItem(
					runtime.NewIntMsg(data),
					idx,
					last,
				)

				select {
				case <-ctx.Done():
					return
				case dataOut <- item:
				}

				idx++
				data++
			}
		}
	}, nil
}