Support for match with quoted pattern

src/main/java/org/jsoup/parser/TokenQueue.java

@@ -264,6 +264,7 @@ public String chompBalanced(char open, char close) {
         char last = 0;
         boolean inSingleQuote = false;
         boolean inDoubleQuote = false;
+        boolean inRegexQE = false; // regex \Q .. \E escapes from Pattern.quote()
 
         do {
             if (isEmpty()) break;
@@ -273,8 +274,10 @@ public String chompBalanced(char open, char close) {
                     inSingleQuote = !inSingleQuote;
                 else if (c == '"' && c != open && !inSingleQuote)
                     inDoubleQuote = !inDoubleQuote;
-                if (inSingleQuote || inDoubleQuote)
+                if (inSingleQuote || inDoubleQuote || inRegexQE){
+                    last = c;
                     continue;
+                }
 
                 if (c == open) {
                     depth++;
@@ -283,6 +286,10 @@ else if (c == '"' && c != open && !inSingleQuote)
                 }
                 else if (c == close)
                     depth--;
+            } else if (c == 'Q') {
+                inRegexQE = true;
+            } else if (c == 'E') {
+                inRegexQE = false;
             }
 
             if (depth > 0 && last != 0)

src/main/java/org/jsoup/select/Selector.java

@@ -73,6 +73,8 @@
  * <tr><td><code>:empty</code></td><td>elements that have no children at all</td><td></td></tr>
  * </table>
  *
+ * <p>A word on using regular expressions in these selectors: depending on the content of the regex, you will need to quote the pattern using <b><code>Pattern.quote("regex")</code></b> for it to parse correclty through both the selector parser and the regex parser. E.g. <code>String query = "div:matches(" + Pattern.quote(regex) + ");"</code>.</p>
+ *
  * @author Jonathan Hedley, jonathan@hedley.net
  * @see Element#select(String)
  */

src/test/java/org/jsoup/parser/TokenQueueTest.java

@@ -1,8 +1,11 @@
 package org.jsoup.parser;
 
 import org.jsoup.Jsoup;
+import org.jsoup.nodes.Document;
 import org.junit.jupiter.api.Test;
 
+import java.util.regex.Pattern;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.fail;
 
@@ -95,4 +98,12 @@ public void chompBalancedThrowIllegalArgumentException() {
             assertEquals("Did not find balanced marker at 'something(or another)) else'", expected.getMessage());
         }
     }
+
+    @Test
+    public void testQuotedPattern() {
+        final Document doc = Jsoup.parse("<div>\\) foo1</div><div>( foo2</div><div>1) foo3</div>");
+        assertEquals("\n\\) foo1",doc.select("div:matches(" + Pattern.quote("\\)") + ")").get(0).childNode(0).toString());
+        assertEquals("\n( foo2",doc.select("div:matches(" + Pattern.quote("(") + ")").get(0).childNode(0).toString());
+        assertEquals("\n1) foo3",doc.select("div:matches(" + Pattern.quote("1)") + ")").get(0).childNode(0).toString());
+    }
 }