* XML entities. This method replaces the following characters:
     * <ul>
     *   <li>&amp; with &amp;amp;</li>
     *   <li>&lt; with &amp;lt;</li>
     *   <li>&gt; with &amp;gt;</li>
     *   <li>" with &amp;quot;</li>
     *   <li>' with &amp;apos;</li>
     * </ul>
     * Additionally, it strips invalid XML characters from the input string.
     *

    def parsesHtmlEntities() {
        when:
        lexer.pushText("before & after")
        lexer.visit(visitor)

        then:
        1 * visitor.onText('before & after')
        1 * visitor.onEnd()
        0 * visitor._
    }

    def parsesStartHtmlElementWithAttributes() {
        when:
        lexer.pushText("<a name='value' other='\n&amp; &apos;\n \"'>")
        lexer.visit(visitor)

        then:

                                                            <la:link
                                                                    href="/admin/searchlist/edit?crudMode=2&amp;doc.doc_id=${f:u(doc.doc_id)}&amp;q=${f:u(q)}"
                                                                    styleClass="btn btn-primary btn-xs">

 * general way.
 *
 * <p>A good example of usage of this class is for HTML escaping where the replacement array
 * contains information about the named HTML entities such as {@code &amp;} and {@code &quot;} while
 * {@link #escapeUnsafe} is overridden to handle general escaping of the form {@code &#NNNNN;}.
 *
 * <p>The size of the data structure used by {@link ArrayBasedUnicodeEscaper} is proportional to the

   *       the same.
   *   <li>The unreserved characters ".", "-", "~", and "_" remain the same.
   *   <li>The general delimiters "@" and ":" remain the same.
   *   <li>The subdelimiters "!", "$", "&amp;", "'", "(", ")", "*", "+", ",", ";", and "=" remain
   *       the same.
   *   <li>The space character " " is converted into %20.
   *   <li>All other characters are converted into one or more bytes using UTF-8 encoding and each

            }

            target.append("</${element.tagName}>")

            return
        }

        if (node instanceof Text) {
            target.append(node.nodeValue.replace('&', '&amp;').replace('<', '&lt;').replace('>', '&gt;'))
            return
        }

        throw new UnsupportedOperationException("Don't know how to format DOM node: $node")
    }

     *
     * Valid URL characters include:
     * - Lowercase letters (a-z)
     * - Uppercase letters (A-Z)
     * - Digits (0-9)
     * - Special characters: . - * _ : / + % = & ? # [ ] @ ~ ! $ ' ( ) , ;
     *
     * @param c the character to check
     * @return {@code true} if the character is a valid URL character, {@code false} otherwise
     */
    public static boolean isUrlChar(final char c) {

   *       the same.
   *   <li>The unreserved characters ".", "-", "~", and "_" remain the same.
   *   <li>The general delimiters "@" and ":" remain the same.
   *   <li>The subdelimiters "!", "$", "&amp;", "'", "(", ")", "*", "+", ",", ";", and "=" remain
   *       the same.
   *   <li>The space character " " is converted into %20.
   *   <li>All other characters are converted into one or more bytes using UTF-8 encoding and each

            case '<':
                buf.append("&lt;");
                break;
            case '>':
                buf.append("&gt;");
                break;
            case '&':
                buf.append("&amp;");
                break;
            case '"':
                buf.append("&quot;");
                break;
            default:
                buf.append(element);
            }
        }

</p>
<pre class="grammar">
+    &amp;     +=    &amp;=     &amp;&amp;    ==    !=    (    )
-    |     -=    |=     ||    &lt;     &lt;=    [    ]
*    ^     *=    ^=     &lt;-    &gt;     &gt;=    {    }
/    &lt;&lt;    /=    &lt;&lt;=    ++    =     :=    ,    ;
%    &gt;&gt;    %=    &gt;&gt;=    --    !     ...   .    :
     &amp;^          &amp;^=          ~
</pre>