checker.py 文件源码

def IMPORTFROM(self, node):
        if node.module == '__future__':
            if not self.futuresAllowed:
                self.report(messages.LateFutureImport,
                            node, [n.name for n in node.names])
        else:
            self.futuresAllowed = False

        module = ('.' * node.level) + (node.module or '')

        for alias in node.names:
            name = alias.asname or alias.name
            if node.module == '__future__':
                importation = FutureImportation(name, node, self.scope)
                if alias.name not in __future__.all_feature_names:
                    self.report(messages.FutureFeatureNotDefined,
                                node, alias.name)
            elif alias.name == '*':
                # Only Python 2, local import * is a SyntaxWarning
                if not PY2 and not isinstance(self.scope, ModuleScope):
                    self.report(messages.ImportStarNotPermitted,
                                node, module)
                    continue

                self.scope.importStarred = True
                self.report(messages.ImportStarUsed, node, module)
                importation = StarImportation(module, node)
            else:
                importation = ImportationFrom(name, node,
                                              module, alias.name)
            self.addBinding(node, importation)