fixed line indexing

reader.go

@@ -18,7 +18,7 @@ func New(r io.Reader) *Reader {
 	return &Reader{
 		buf: ds.NewArrayStack[posRune](),
 		src: bufio.NewReader(r),
-		pos: &Position{},
+		pos: &Position{Index: 0, Line: 1, Column: 0},
 	}
 }