namedlist.py 文件源码

def _make_fn(name, chain_fn, args, defaults):
    args_with_self = ['_self'] + list(args)
    arguments = [_ast.Name(id=arg, ctx=_ast.Load()) for arg in args_with_self]
    defs = [_ast.Name(id='_def{0}'.format(idx), ctx=_ast.Load()) for idx, _ in enumerate(defaults)]
    if _PY2:
        parameters = _ast.arguments(args=[_ast.Name(id=arg, ctx=_ast.Param()) for arg in args_with_self],
                                    defaults=defs)
    else:
        parameters = _ast.arguments(args=[_ast.arg(arg=arg) for arg in args_with_self],
                                    kwonlyargs=[],
                                    defaults=defs,
                                    kw_defaults=[])
    module_node = _ast.Module(body=[_ast.FunctionDef(name=name,
                                                     args=parameters,
                                                     body=[_ast.Return(value=_ast.Call(func=_ast.Name(id='_chain', ctx=_ast.Load()),
                                                                                       args=arguments,
                                                                                       keywords=[]))],
                                                     decorator_list=[])])
    module_node = _ast.fix_missing_locations(module_node)

    # compile the ast
    code = compile(module_node, '<string>', 'exec')

    # and eval it in the right context
    globals_ = {'_chain': chain_fn}
    locals_ = dict(('_def{0}'.format(idx), value) for idx, value in enumerate(defaults))
    eval(code, globals_, locals_)

    # extract our function from the newly created module
    return locals_[name]


########################################################################
# Produce a docstring for the class.