Builds a parameter filter using the supplied pattern (may be a
        general Python regular expression)

def regexp_filter(self_or_cls, pattern):
        """
        Builds a parameter filter using the supplied pattern (may be a
        general Python regular expression)
        """
        def inner_filter(name, p):
            name_match = re.search(pattern,name)
            if name_match is not None:
                return True
            doc_match = re.search(pattern,p.doc)
            if doc_match is not None:
                return True
            return False
        return inner_filter