Minor cleanup

Author: rayokota

src/main/java/com/dashjoin/jsonata/Tokenizer.java

@@ -142,7 +142,11 @@ Pattern scanRegex() {
                 start = position;
                 while (currentChar == 'i' || currentChar == 'm') {
                     position++;
-                    currentChar = path.charAt(position);
+                    if (position < length) {
+                        currentChar = path.charAt(position);
+                    } else {
+                        currentChar = 0;
+                    }
                 }
                 flags = path.substring(start, position) + 'g';
 

src/test/java/com/dashjoin/jsonata/StringTest.java

@@ -1,6 +1,7 @@
 package com.dashjoin.jsonata;
 
 import static com.dashjoin.jsonata.Jsonata.jsonata;
+
 import java.util.Arrays;
 import java.util.Map;
 import org.junit.jupiter.api.Assertions;
@@ -127,4 +128,18 @@ public void evalTest() {
         + "  $eval('$data.Wert1')\n"
         + ")").evaluate(null));
   }
+
+  @Test
+  public void regexTest() {
+    Assertions.assertEquals(Map.of("foo", 1), jsonata(
+        "($matcher := $eval('/^' & 'foo' & '/i'); $.$spread()[$.$keys() ~> $matcher])")
+        .evaluate(Map.of("foo", 1, "bar", 2)));
+  }
+  
+  @Disabled
+  @Test
+  public void replaceTest() {
+    Assertions.assertEquals("http://example.org/test", 
+        jsonata("$replace($, /{par}/, '')").evaluate("http://example.org/test{par}"));
+  }
 }