r equality only.
		The default value for this field is <code>nil</code>.
	</dd>
	
</dl>

<h3>Methods</h3>

<dl>
	
	<dt><code><b>error</b>(reason)</code></dt>
	<dd>
		Method that creates a matching error message.
		The parameter <code>reason</code> is a string with a message describing the error reason.
		Whenever this method is called, the object instance stores as an array (<i>i.e.</i> using integer keys) the sequence of values that identifies the path to the mismatched field.
		However, indexes 0 and 1 ar