'Construct a new ``UnChunkRule``.
:type tag_pattern: str
:param tag_pattern: This rule\'s tag pattern.  When
applied to a ``ChunkString``, this rule will
find any complete chunk that matches this tag pattern,
and un-chunk it.
:type descr: str
:param descr: A short description of the purpose and/or effect
of this rule.'

def __init__(self, tag_pattern, descr):

    self._pattern = tag_pattern
    regexp = re.compile((u'\\{(?P<chunk>%s)\\}' % tag_pattern2re_pattern(tag_pattern)))
    RegexpChunkRule.__init__(self, regexp, u'\\g<chunk>', descr)
