From 85d52b02e5eb9060d10e766830644dda94510e1e Mon Sep 17 00:00:00 2001
From: Sergeev Viktor <sergeevViktor017@gmail.com>
Date: Wed, 28 Jan 2026 03:35:22 +0300
Subject: [PATCH] ISSUES-88: add check value of position in while cycle after
 increment

---
 .../java/com/dashjoin/jsonata/Tokenizer.java  |  6 ++++-
 .../java/com/dashjoin/jsonata/RegexTest.java  | 22 +++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 src/test/java/com/dashjoin/jsonata/RegexTest.java

diff --git a/src/main/java/com/dashjoin/jsonata/Tokenizer.java b/src/main/java/com/dashjoin/jsonata/Tokenizer.java
index 308b006..1da1ec9 100644
--- a/src/main/java/com/dashjoin/jsonata/Tokenizer.java
+++ b/src/main/java/com/dashjoin/jsonata/Tokenizer.java
@@ -139,7 +139,11 @@ Pattern scanRegex() {
                     throw new JException("S0301", position);
                 }
                 position++;
-                currentChar = path.charAt(position);
+                if (position < length) {
+                    currentChar = path.charAt(position);
+                } else {
+                    currentChar = 0;
+                }
                 // flags
                 start = position;
                 while (currentChar == 'i' || currentChar == 'm') {
diff --git a/src/test/java/com/dashjoin/jsonata/RegexTest.java b/src/test/java/com/dashjoin/jsonata/RegexTest.java
new file mode 100644
index 0000000..079fb12
--- /dev/null
+++ b/src/test/java/com/dashjoin/jsonata/RegexTest.java
@@ -0,0 +1,22 @@
+package com.dashjoin.jsonata;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class RegexTest {
+    @Test
+    public void testRegex() {
+        var expression = Jsonata.jsonata("/^test.*$/");
+        Object evaluate = expression.evaluate(null);
+        String expected = "^test.*$";
+        Assertions.assertEquals(expected, evaluate.toString());
+    }
+
+    @Test
+    public void testEvalRegex() {
+        var expression = Jsonata.jsonata("$eval('/^test.*$/')");
+        Object evaluate = expression.evaluate(null);
+        String expected = "^test.*$";
+        Assertions.assertEquals(expected, evaluate.toString());
+    }
+}