regexp.py 文件源码

def parse(self, chunk_struct, trace=None):
        """
        :type chunk_struct: Tree
        :param chunk_struct: the chunk structure to be (further) chunked
        :type trace: int
        :param trace: The level of tracing that should be used when
            parsing a text.  ``0`` will generate no tracing output;
            ``1`` will generate normal tracing output; and ``2`` or
            highter will generate verbose tracing output.  This value
            overrides the trace level value that was given to the
            constructor.
        :rtype: Tree
        :return: a chunk structure that encodes the chunks in a given
            tagged sentence.  A chunk is a non-overlapping linguistic
            group, such as a noun phrase.  The set of chunks
            identified in the chunk structure depends on the rules
            used to define this ``RegexpChunkParser``.
        """
        if len(chunk_struct) == 0:
            print('Warning: parsing empty text')
            return Tree(self._root_label, [])

        try:
            chunk_struct.label()
        except AttributeError:
            chunk_struct = Tree(self._root_label, chunk_struct)

        # Use the default trace value?
        if trace is None: trace = self._trace

        chunkstr = ChunkString(chunk_struct)

        # Apply the sequence of rules to the chunkstring.
        if trace:
            verbose = (trace>1)
            self._trace_apply(chunkstr, verbose)
        else:
            self._notrace_apply(chunkstr)

        # Use the chunkstring to create a chunk structure.
        return chunkstr.to_chunkstruct(self._chunk_label)