Error investigation configurable

js/markdown.js

 	 */
 	tagFilter = new MDHTMLFilter();
 
+	/**
+	 * If an exception occurs, attempts to narrow down the portion of the
+	 * markdown that triggered the error and outputs it to the console. For
+	 * debugging. Investigation mode can be slow.
+	 */
+	investigateErrors = false;
+
 	/** @type {MDReader[]} */
 	#readers;
 
 		try {
 			return this.#parse(lines, elementIdPrefix);
 		} catch (e) {
-			this.#investigateException(lines, elementIdPrefix);
+			if (this.investigateErrors) {
+				this.#investigateException(lines, elementIdPrefix);
+			}
 			throw e;
 		}
 	}

php/markdown.php

 	 */
 	public MDHTMLFilter $tagFilter;
 
+	/**
+	 * If an exception occurs, attempts to narrow down the portion of the
+	 * markdown that triggered the error and outputs it to the console. For
+	 * debugging. Investigation mode can be slow.
+	 */
+	public bool $investigateErrors = false;
+
 	/** @var MDReader[] */
 	private array $readers;
 
 		try {
 			return $this->parse($lines, $elementIdPrefix);
 		} catch (Error $e) {
-			$this->investigateException($lines, $elementIdPrefix);
+			if ($this->investigateErrors) {
+				$this->investigateException($lines, $elementIdPrefix);
+			}
 			throw $e;
 		}
 	}

php/test.php

+<?php
+include 'markdown.php';
+include 'spreadsheet.php';
+
+$address = 'C6';
+if (mb_eregi('^(\\$?)([A-Z]{1,2}?)((?:\\$(?=[0-9]))?)([0-9]*)$', $address, $groups)) {
+    print("Matched\n");
+    print_r($groups);
+} else {
+    print("No match!\n");
+}
+
+?>