wc-like counter.go

package main

import (
	"bufio"
	"fmt"
	"io"
	"log"
	"strings"
	"unicode"
)

var text = `
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor
incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute
irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla
pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui
officia deserunt mollit anim id est laborum.
`

func main() {
	var chars, runes, words, lines int
	var inWord bool

	buf := bufio.NewReader(strings.NewReader(text))
	for {
		r, sz, err := buf.ReadRune()
		if err != nil {
			if err == io.EOF {
				if inWord {
					words++
					inWord = false
				}
				break
			} else {
				log.Fatal(err)
			}
		}

		runes++
		chars += sz

		if unicode.IsSpace(r) {
			if r == '\n' {
				lines++
			}
			if inWord {
				words++
				inWord = false
			}
		} else if unicode.IsPunct(r) || unicode.IsControl(r) {
			if inWord {
				words++
				inWord = false
			}
		} else {
			inWord = true
		}
	}

	fmt.Printf("%8d %7d %7d %7d\n", lines, words, chars, runes)
}

Running version is here - http://play.golang.org/p/tL3NFziKft