From 333b6bc91b2f7dbfa4af1e740cded2e978593c89 Mon Sep 17 00:00:00 2001
From: CorentinGS <contact@corentings.dev>
Date: Wed, 18 Dec 2024 17:57:41 +0100
Subject: [PATCH 1/4] fix: Use errors.Is for EOF error comparison in tests

closes #12
---
 polyglot_test.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/polyglot_test.go b/polyglot_test.go
index e5be5e4..01a867c 100644
--- a/polyglot_test.go
+++ b/polyglot_test.go
@@ -3,6 +3,7 @@ package chess
 import (
 	"bytes"
 	"encoding/binary"
+	"errors"
 	"io"
 	"os"
 	"path/filepath"
@@ -60,7 +61,7 @@ func TestBytesBookSource(t *testing.T) {
 	// Test EOF
 	source.index = 32
 	n, err = source.Read(buf)
-	if err != io.EOF {
+	if !errors.Is(err, io.EOF) {
 		t.Errorf("Read() error = %v, want EOF", err)
 	}
 }

From 52dd184cfa8846e21e2a83a1a34178a94f356a88 Mon Sep 17 00:00:00 2001
From: CorentinGS <contact@corentings.dev>
Date: Wed, 18 Dec 2024 17:58:45 +0100
Subject: [PATCH 2/4] fix: error variable naming in loop for clarity.

closes  #11
---
 polyglot.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/polyglot.go b/polyglot.go
index af56927..ae6f2ed 100644
--- a/polyglot.go
+++ b/polyglot.go
@@ -194,12 +194,12 @@ func LoadFromSource(source BookSource) (*PolyglotBook, error) {
 
 	buf := make([]byte, 16)
 	for {
-		_, err := source.Read(buf)
-		if err == io.EOF {
+		_, readErr := source.Read(buf)
+		if readErr == io.EOF {
 			break
 		}
-		if err != nil {
-			return nil, err
+		if readErr != nil {
+			return nil, readErr
 		}
 
 		entry := PolyglotEntry{

From 5d47fd2d41bfb0f28823bdc1a0d552b3704e8a6a Mon Sep 17 00:00:00 2001
From: CorentinGS <contact@corentings.dev>
Date: Wed, 18 Dec 2024 18:00:35 +0100
Subject: [PATCH 3/4] fix: potential nil pointer closes:  #8

---
 pgn.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pgn.go b/pgn.go
index e9fa8ea..5947e9d 100644
--- a/pgn.go
+++ b/pgn.go
@@ -519,7 +519,7 @@ func (p *Parser) parseVariation() error {
 		// the last move before the variation start
 		variationParent = parentMove.parent
 		// Reset position to where the variation starts
-		if variationParent.parent != nil {
+		if variationParent.parent != nil && variationParent.parent.position != nil {
 			p.game.pos = variationParent.parent.position.copy()
 			if newPos := p.game.pos.Update(variationParent); newPos != nil {
 				p.game.pos = newPos

From 878381046c88e6ee16234e4d07d73b9d4f4df448 Mon Sep 17 00:00:00 2001
From: CorentinGS <contact@corentings.dev>
Date: Wed, 18 Dec 2024 18:01:52 +0100
Subject: [PATCH 4/4] fix: Add "Undefined" token type to lexer

closes #6
---
 lexer.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lexer.go b/lexer.go
index 63ae242..a3057c4 100644
--- a/lexer.go
+++ b/lexer.go
@@ -44,6 +44,7 @@ const (
 func (t TokenType) String() string {
 	types := []string{
 		"EOF",
+		"Undefined",
 		"TagStart",
 		"TagEnd",
 		"TagKey",