es passed as parameters.
		The function must return <code>true</code> if the values match or <code>false</code> otherwise.
		If this field evaluates to <code>false</code> then thread values are compared for equality only.
		The default value for this field is <code>nil</code>.
	</dd>
	
	<dt><code><b>upvalue</b></code></dt>
	<dd>
		Field that defines the function used to retrieve the contents of function upvalues.
		If this field evaluates to <code>false</code> then upvalues contents are ignored during match