// New returns a new scanner lexing from r.
func New(r io.Reader) (Scanner, error) {
toks, err := lexer.Parse(r)
if err != nil {
return nil, err
}
return &scanner{toks: toks}, nil
}
// lexFileHand lexes the given file and pretty-prints the n first tokens to
// standard output, using the hand-written lexer.
func lexFileHand(path string, n int) (err error) {
var toks []token.Token
if path == "-" {
fmt.Fprintln(os.Stderr, "Lexing from standard input")
toks, err = lexer.Parse(os.Stdin)
} else {
fmt.Fprintf(os.Stderr, "Lexing %q\n", path)
toks, err = lexer.ParseFile(path)
}
if err != nil {
return errutil.Err(err)
}
ntoks := len(toks)
if n > ntoks {
ntoks = n
}
pad := int(math.Ceil(math.Log10(float64(ntoks))))
for i, tok := range toks {
if n != 0 && i == n {
break
}
if tok.Kind == token.Error {
elog.Printf("ERROR %*d: %v\n", pad, i, tok)
} else {
fmt.Printf("token %*d: %v\n", pad, i, tok)
}
}
fmt.Fprintln(os.Stderr)
return nil
}