fixed IsWhitespace function consideres tabs as whitespace

reader.go

@@ -33,8 +33,8 @@ func (r *Reader) psrn(rn rune) posRune {
 	}
 }
 
-func (r *Reader) Pos() (index, line, column int) {
+func (r *Reader) Pos() Position {
-	return r.pos.Index, r.pos.Line, r.pos.Column
+	return *r.pos
 }
 
 // Rune returns the next rune in r

reader_test.go

@@ -11,8 +11,8 @@ func TestPos(t *testing.T) {
 
 	unread := false
 	for rn, err := r.Rune(); err == nil; rn, err = r.Rune() {
-		index, line, col := r.Pos()
+		pos := r.Pos()
-		fmt.Println(string(rn), index, line, col)
+		fmt.Println(string(rn), pos.Index, pos.Line, pos.Column)
 
 		if !unread && rn == '\n' {
 			for i := 0; i < 5; i++ {

runefunc.go

@@ -12,8 +12,12 @@ func IsSpace(rn rune) bool {
 	return rn == ' '
 }
 
+func IsTab(rn rune) bool {
+	return rn == '\t'
+}
+
 func IsWhitespace(rn rune) bool {
-	return IsSpace(rn) || IsNewLine(rn)
+	return IsSpace(rn) || IsTab(rn) || IsNewLine(rn)
 }
 
 func And(f ...RuneFunc) RuneFunc {