Golang go/scanner.Scanner type example

package go/scanner

A Scanner holds the scanner's internal state while processing a given text. It can be allocated as part of another data structure but must be initialized via Init before use.

Golang go/scanner.Scanner type usage example

 func tokenSelection(src []byte, sel token.Token) Selection {
 var s scanner.Scanner
 fset := token.NewFileSet()
 file := fset.AddFile("", fset.Base(), len(src))
 s.Init(file, src, nil, scanner.ScanComments)
 ...
 }

Reference :

http://golang.org/pkg/go/scanner/#Scanner