Slice support.

scanner.go

@@ -60,18 +60,21 @@ func (t Token) IsValue() bool {
 }
 
 type Scanner struct {
-	raw  []string
 	args []Token
 }
 
 func Scan(args ...string) *Scanner {
-	s := &Scanner{raw: args}
+	s := &Scanner{}
 	for _, arg := range args {
 		s.args = append(s.args, Token{Value: arg})
 	}
 	return s
 }
 
+func (s *Scanner) Len() int {
+	return len(s.args)
+}
+
 func (s *Scanner) Pop() Token {
 	if len(s.args) == 0 {
 		return Token{Type: EOLToken}