如何定義一個裝飾，將一個函數/方法調用

我不夠好與裝飾還沒有做到這一點...提供插值文檔字符串是否有可能定義一個裝飾live_doc，讓我在方法或函數調用之後獲取插入的doc字符串，並用實際參數和返回值填充。如何定義一個裝飾，將一個函數/方法調用

@live_doc("f was called with %d, %s and returned %d") 
def f(x, y): 
    x + len(y)

下面的代碼後：

f(3, "marty") 

d = f.doc

d應該是「F被稱爲與3中，」馬蒂「，並返回8」。我希望在f.doc被訪問之前不要建立字符串，但是肯定需要在某處鬆開呼叫參數返回值。

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2012-11-29 Des

這裏有一個稍微廣義的解決方案，將視您的原始文檔字符串爲模板，並維持其他有關裝飾功能（正如其名）：在交互式解釋

from functools import wraps 

def live_doc(func): 
    template = func.__doc__ 
    @wraps(func) 
    def wrapper(*args, **kwargs): 
     ret_val = func(*args, **kwargs) 
     args_pretty = ", ".join(repr(a) for a in args) 
     kw_pretty = ", ".join("%s=%r" % (k, v) for k, v in kwargs.items()) 
     signature = ", ".join(x for x in (args_pretty, kw_pretty) if x) 
     name = func.__name__ 
     wrapper.__doc__ = template % locals() 
     return ret_val 
    return wrapper 

@live_doc 
def f(x, y): 
    """%(name)s was called with %(signature)s and returned %(ret_val)r.""" 
    return x + len(y)

f之前首先被調用，help(f)爲您提供：

Help on function f in module __main__: 

f(*args, **kwargs) 
    %(name)s was called with %(signature)s and returned %(ret_val)r.

這就是所謂的後，你會得到：

f(*args, **kwargs) 
    f was called with 3, 'marty' and returned 8.

或者用一個更一般的功能，炫耀kwargs：

@live_doc 
def q(*args, **kwargs): 
    """%(name)s was called with %(signature)s and returned %(ret_val)r.""" 
    return len(args) + len(kwargs) 

>>> q(1, 2, 3, a=7, b="foo") 
5 
>>> help(q) 
q(*args, **kwargs) 
    q was called with 1, 2, 3, a=7, b='foo' and returned 5.

很明顯，你可以創建你想在模板裏面使用wrapper任何變量。

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2012-11-29 05:30:04

這是我的代碼，（我感到非常愚蠢的寫作，所以我可能會做一些錯誤，特別是在t中間部分）：

def live_doc(d): 
    def f_d(f): 
     def f_new(*args): 
      r = f(*args) 
      t = [a for a in args] 
      t.append(r) 
      t = tuple(t) 
      f_new.doc = d % t 
      return r 
     return f_new 
    return f_d 

@live_doc("f was called with %d, %s and returned %d") 
def f(x,y): 
    return x + len(y) 

f(1,"hi") 
print(f.doc) 
// f was called with 1, hi and returned 3

我從http://www.python.org/dev/peps/pep-0318/使用的

@decomaker(argA, argB, ...) 
def func(arg1, arg2, ...): 
    pass

相當於

func = decomaker(argA, argB, ...)(func)

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2012-11-29 04:32:48

我想出了這一點：

#!/usr/bin/env python 

def docme(func): 
    def wrap(*args, **kwargs): 
     retval = None 
     wrap.__doc__ = wrap.__olddoc__ + """ 

Last called with args: %s, %s 
""" % (args, kwargs) 
     try: 
      retval = func(*args, **kwargs) 
      wrap.__doc__ += 'Last returned: %s' % retval 
      return retval 
     except Exception as exc: 
      wrap.__doc__ += 'Failed and raised: %r' % exc 
      raise 

    wrap.__doc__ = func.__doc__ + '\n\nHas not been called yet' 
    wrap.__name__ = func.__name__ 
    wrap.__olddoc__ = func.__doc__ 
    return wrap 

@docme 
def foo(x): 
    """foo docs""" 
    if x == 1: 
     raise ValueError('baz') 
    return x * 2

它保持了函數的文檔字符串，所以你仍然可以調用help(foo)讀取其指令。每次調用，它將更新與參數和結果文檔字符串（或除外它提出）：

>>> print foo.__doc__ 
foo docs 

Has not been called yet 
>>> foo(2) 
4 
>>> print foo.__doc__ 
foo docs 

Last called with args: (2,), {} 
Last returned: 4 
>>> foo(1) 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
    File "/tmp/foo.py", line 11, in wrap 
    retval = func(*args, **kwargs) 
    File "/tmp/foo.py", line 27, in foo 
    raise ValueError('baz') 
ValueError: baz 
>>> print foo.__doc__ 
foo docs 

Last called with args: (1,), {} 
Failed and raised: ValueError('baz',)

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2012-11-29 05:18:08

如何定義一個裝飾，將一個函數/方法調用

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