关于python：如何从类中的方法动态创建模块级函数

How to dynamically create module level functions from methods in a class

我正在尝试从类中的方法动态创建模块级函数。因此，对于类中的每个方法，我希望创建一个同名的函数，该函数创建类的一个实例，然后调用该方法。

我之所以要这样做，是因为我可以采用面向对象的方法来创建结构文件。由于结构将调用模块级函数而不是类的方法，所以这是我的工作。

我已使用以下链接开始

如何获取Python类中的方法列表？
向python模块动态添加函数
如何在当前模块上调用setattr()？
http://effbot.org/zone/python-getattr.htm网站
从字符串中调用模块的函数，该字符串的函数名为python
如何在python中修改本地命名空间

我想出了以下代码

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import inspect
import sys
import types

class TestClass(object):
def __init__(self):
pass

def method1(self, arg1):
print 'method 1 %s' % arg1

def method2(self):
print 'method 2'

def fabric_class_to_function_magic(module_name):
# get the module as an object
print module_name
module_obj = sys.modules[module_name]
print dir(module_obj)

# Iterate over the methods of the class and dynamically create a function
# for each method that calls the method and add it to the current module
for method in inspect.getmembers(TestClass, predicate=inspect.ismethod):
print
print method
method_name, method_obj = method

# create a new template function which calls the method
def newfunc_template(*args, **kwargs):
tc = TestClass()
func = getattr(tc, method_name)
return func(*args, **kwargs)

# create the actual function
print 'code: ', newfunc_template.func_code
print 'method_name: ', method_name
newfunc = types.FunctionType(newfunc_template.func_code,
{'TestClass': TestClass,
'getattr': getattr,
'method_name': method_name,
},
name=method_name,
argdefs=newfunc_template.func_defaults,
closure=newfunc_template.func_closure,
)

# add the new function to the current module
setattr(module_obj, method_name, newfunc)

# test the dynamically created module level function
thismodule = sys.modules[__name__]
print dir(thismodule)
fabric_class_to_function_magic(__name__)
print dir(thismodule)
method1('arg1')
method2()

我得到以下错误

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['TestClass', '__builtins__', '__doc__', '__file__', '__name__', '__package__', 'fabric_class_to_function_magic', 'inspect', 'sys', 'thismodule', 'types']
__main__
['TestClass', '__builtins__', '__doc__', '__file__', '__name__', '__package__', 'fabric_class_to_function_magic', 'inspect', 'sys', 'thismodule', 'types']

('__init__', <unbound method TestClass.__init__>)
code: <code object newfunc_template at 0x7f8800a28d50, file"test.py", line 85>
method_name: __init__

('method1', <unbound method TestClass.method1>)
code: <code object newfunc_template at 0x7f8800a28d50, file"test.py", line 85>
method_name: method1

('method2', <unbound method TestClass.method2>)
code: <code object newfunc_template at 0x7f8800a28d50, file"test.py", line 85>
method_name: method2
['TestClass', '__builtins__', '__doc__', '__file__', '__init__', '__name__', '__package__', 'fabric_class_to_function_magic', 'inspect', 'method1', 'method2', 'sys', 'thismodule', 'types']
Traceback (most recent call last):
File"test.py", line 111, in <module>
method1('arg1')
File"test.py", line 88, in newfunc_template
return func(*args, **kwargs)
TypeError: method2() takes exactly 1 argument (2 given)

它似乎在重用对函数的引用？有什么想法吗？

更新：这是NedBatchelder的修复程序的工作代码

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def fabric_class_to_function_magic(module_name):
# get the module as an object
module_obj = sys.modules[module_name]

# Iterate over the methods of the class and dynamically create a function
# for each method that calls the method and add it to the current module
for method in inspect.getmembers(TestClass, predicate=inspect.ismethod):
method_name, method_obj = method

# get the bound method
tc = TestClass()
func = getattr(tc, method_name)

# add the function to the current module
setattr(module_obj, method_name, func)

更新2：这是我关于这个主题的博客文章：http://www.saltycrane.com/blog/2010/09/class-based-fabric-scripts-metaprogramming-hack/