cli.py 文件源码

def __init__(self, expr):
        self.expr = expr
        self.ns = {}
        try:
            tree = ast.parse(expr)
        except SyntaxError as exc:
            raise argparse.ArgumentTypeError('Invalid service spec %r. Parse error:\n'
                                             '  %s %s^\n'
                                             '%s' % (expr, exc.text, ' '*exc.offset, exc))
        for node in ast.walk(tree):
            if isinstance(node, ast.Name):
                if not hasattr(builtins, node.id):
                    try:
                        __import__(node.id)
                    except ImportError as exc:
                        raise argparse.ArgumentTypeError('Invalid service spec %r. Import error: %s' % (expr, exc))
                    self.ns[node.id] = sys.modules[node.id]