e it prefers a complete match over a partial match.
All the various matching items in a pattern behave as if the subject string is
potentially complete. For example, \z, \Z, and $ match at the end of the
subject, as normal, and for \b and \B the end of the subject is treated as a
non-alphanumeric.
</P>
<P>
If there is more than one partial match, the first one that was found provides
the data that is returned. Consider this pattern:
<pre>
  /123\w+X|dogY/
</pre>
If this is matched against the subject string