refactor.py 文件源码

def _get_headnode_dict(fixer_list):
    """ Accepts a list of fixers and returns a dictionary
        of head node type --> fixer list.  """
    head_nodes = collections.defaultdict(list)
    every = []
    for fixer in fixer_list:
        if fixer.pattern:
            try:
                heads = _get_head_types(fixer.pattern)
            except _EveryNode:
                every.append(fixer)
            else:
                for node_type in heads:
                    head_nodes[node_type].append(fixer)
        else:
            if fixer._accept_type is not None:
                head_nodes[fixer._accept_type].append(fixer)
            else:
                every.append(fixer)
    for node_type in chain(pygram.python_grammar.symbol2number.itervalues(),
                           pygram.python_grammar.tokens):
        head_nodes[node_type].extend(every)
    return dict(head_nodes)