read until EOF

main.go

package main

import (
	"bufio"
	"fmt"
	"os"
	"io"
	"log"
)

type LineIterator struct {
	reader *bufio.Reader
}

func NewLineIterator(rd io.Reader) *LineIterator {
	return &LineIterator{
		reader: bufio.NewReader(rd),
	}
}

func (ln *LineIterator) Next() ([]byte, error) {
	var bytes []byte
	for {
		line, isPrefix, err := ln.reader.ReadLine()
		if err != nil {
			return nil, err
		}
		bytes = append(bytes, line...)
		if !isPrefix {
			break
		}
	}
	return bytes, nil
}

// 肝心のmain関数があまり短くならないので意味があるか微妙…
func main() {
	ln := NewLineIterator(os.Stdin)
	for {
		line, err := ln.Next()
		if err != nil {
			if err == io.EOF {
				break
			} else {
				log.Fatal(err)
			}
		}
		log.Printf("line = %s", line)
	}
}