diff --git a/token.go b/token.go
index d12ac60..5fc5f19 100644
--- a/token.go
+++ b/token.go
@@ -33,7 +33,7 @@ func (tk *Token) String() string {
 			return fmt.Sprintf("%v", tk.Value)
 		}
 	}
-	return fmt.Sprintf("%s", tk.source)
+	return tk.source
 }
 
 func NewToken(row, col int, sym Symbol, source string) *Token {
@@ -71,31 +71,31 @@ func (tk *Token) IsSymbol(sym Symbol) bool {
 	return tk.Sym == sym
 }
 
-func (self *Token) Errorf(template string, args ...any) (err error) {
-	err = fmt.Errorf(fmt.Sprintf("[%d:%d] ", self.row, self.col)+template, args...)
+func (tk *Token) Errorf(template string, args ...any) (err error) {
+	err = fmt.Errorf(fmt.Sprintf("[%d:%d] ", tk.row, tk.col)+template, args...)
 	return
 }
 
-func (self *Token) Error() (err error) {
-	if self.Sym == SymError {
-		if msg, ok := self.Value.(error); ok {
-			err = fmt.Errorf("[%d:%d] %v", self.row, self.col, msg)
+func (tk *Token) Error() (err error) {
+	if tk.Sym == SymError {
+		if msg, ok := tk.Value.(error); ok {
+			err = fmt.Errorf("[%d:%d] %v", tk.row, tk.col, msg)
 		}
 	}
 	return
 }
 
-func (self *Token) Errors(msg string) (err error) {
-	err = fmt.Errorf("[%d:%d] %v", self.row, self.col, msg)
+func (tk *Token) Errors(msg string) (err error) {
+	err = fmt.Errorf("[%d:%d] %v", tk.row, tk.col, msg)
 	return
 }
 
-func (self *Token) ErrorExpectedGot(symbol string) (err error) {
-	err = fmt.Errorf("[%d:%d] expected %q, got %q", self.row, self.col, symbol, self)
+func (tk *Token) ErrorExpectedGot(symbol string) (err error) {
+	err = fmt.Errorf("[%d:%d] expected %q, got %q", tk.row, tk.col, symbol, tk)
 	return
 }
 
-func (self *Token) ErrorExpectedGotString(symbol, got string) (err error) {
-	err = fmt.Errorf("[%d:%d] expected %q, got %q", self.row, self.col, symbol, got)
+func (tk *Token) ErrorExpectedGotString(symbol, got string) (err error) {
+	err = fmt.Errorf("[%d:%d] expected %q, got %q", tk.row, tk.col, symbol, got)
 	return
 }