red during matching.
		The default value for this field is function <code>getfenv</code> of the Lua library.
	</dd>
	
	<dt><code><b>isomorphic</b></code></dt>
	<dd>
		If this field evaluates to <code>true</code> then table matching should be isomorphic, <i>i.e.</i> there is a one to one relation of each field of the first table to the second.
		However, if its value evaluates to <code>false</code> then table matching just guarantee that all fields of the first table have a matching field in the second.
		Th