Python _ast 模块，Dict() 实例源码

def _convert(node):
        if isinstance(node, ast.Str):
            return node.s
        elif isinstance(node, ast.Num):
            return node.n
        elif isinstance(node, ast.Tuple):
            return tuple(map(_convert, node.elts))
        elif isinstance(node, ast.List):
            return list(map(_convert, node.elts))
        elif isinstance(node, ast.Dict):
            return dict((_convert(k), _convert(v)) for k, v
                        in zip(node.keys, node.values))
        elif isinstance(node, ast.Name):
            if node.id in SAFE_CONSTANTS:
                return SAFE_CONSTANTS[node.id]
        raise ValueError('malformed or disallowed expression')

def BUILD_MAP(self, instr):

        nitems = instr.oparg
        keys = []
        values = []
        for i in range(nitems):
            map_instrs = []
            while 1:
                new_instr = self.ilst.pop(0)

                if new_instr.opname == 'STORE_MAP':
                    break

                map_instrs.append(new_instr)

            items = self.decompile_block(map_instrs).stmnt()
            assert len(items) == 2

            values.append(items[0])
            keys.append(items[1])


        list_ = _ast.Dict(keys=keys, values=values, lineno=instr.lineno, col_offset=0)
        self.ast_stack.append(list_)

def _get_literal_value(self, literal):
        '''Utility function to turn AST literals into native Python types

        :param literal: The AST literal to convert
        :return: The value of the AST literal
        '''
        if isinstance(literal, _ast.Num):
            literal_value = literal.n

        elif isinstance(literal, _ast.Str):
            literal_value = literal.s

        elif isinstance(literal, _ast.List):
            return_list = list()
            for li in literal.elts:
                return_list.append(self._get_literal_value(li))
            literal_value = return_list

        elif isinstance(literal, _ast.Tuple):
            return_tuple = tuple()
            for ti in literal.elts:
                return_tuple = return_tuple + (self._get_literal_value(ti),)
            literal_value = return_tuple

        elif isinstance(literal, _ast.Set):
            return_set = set()
            for si in literal.elts:
                return_set.add(self._get_literal_value(si))
            literal_value = return_set

        elif isinstance(literal, _ast.Dict):
            literal_value = dict(zip(literal.keys, literal.values))

        elif isinstance(literal, _ast.Ellipsis):
            # what do we want to do with this?
            literal_value = None

        elif isinstance(literal, _ast.Name):
            literal_value = literal.id

        # NOTE(sigmavirus24): NameConstants are only part of the AST in Python
        # 3. NameConstants tend to refer to things like True and False. This
        # prevents them from being re-assigned in Python 3.
        elif six.PY3 and isinstance(literal, _ast.NameConstant):
            literal_value = str(literal.value)

        # NOTE(sigmavirus24): Bytes are only part of the AST in Python 3
        elif six.PY3 and isinstance(literal, _ast.Bytes):
            literal_value = literal.s

        else:
            literal_value = None

        return literal_value