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POHow to handle & return both properties AND functions missing in a Python class using the __getattr__ function?
 

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  1. POHow to handle & return both properties AND functions missing in a Python class using the __getattr__ function?
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    <p>It is fairly easy to use the <code>__getattr__</code> special method on Python classes to handle either missing properties or functions, but seemingly not both at the same time.</p> <p>Consider this example which handles any property requested which is not defined explicitly elsewhere in the class...</p> <pre><code>class Props: def __getattr__(self, attr): return 'some_new_value' &gt;&gt;&gt; p = Props() &gt;&gt;&gt; p.prop # Property get handled 'some_new_value' &gt;&gt;&gt; p.func('an_arg', kw='keyword') # Function call NOT handled Traceback (most recent call last): File "&lt;console&gt;", line 1, in &lt;module&gt; TypeError: 'str' object is not callable </code></pre> <p>Next, consider this example which handles any function call not defined explicitly elsewhere in the class...</p> <pre><code>class Funcs: def __getattr__(self, attr): def fn(*args, **kwargs): # Do something with the function name and any passed arguments or keywords print attr print args print kwargs return return fn &gt;&gt;&gt; f = Funcs() &gt;&gt;&gt; f.prop # Property get NOT handled &lt;function fn at 0x10df23b90&gt; &gt;&gt;&gt; f.func('an_arg', kw='keyword') # Function call handled func ('an_arg',) {'kw': 'keyword'} </code></pre> <p>The question is how to handle both types of missing attributes in the same <code>__getattr__</code>? How to detect if the attribute requested was in property notation or in method notation with parentheses and return either a value or a function respectively? Essentially I want to handle SOME missing property attributes AND SOME missing function attributes and then resort to default behavior for all the other cases.</p> <p>Advice?</p>
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    1. USMartijn Pieters
    1. USsansjoe
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      1. POHow to handle & return both properties AND functions missing in a Python class using the __getattr__ function?
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    1. COMethods are attributes too; attributes are *always* either a callable (e.g. a method) or some other non-callable type; they are never both at the same time. What are you trying to achieve?
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      1. POHow to handle & return both properties AND functions missing in a Python class using the __getattr__ function?
      1. USMartijn Pieters
    2. CO"I want to handle SOME missing property attributes AND SOME missing function attributes and then resort to default behavior for all the other cases."
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      1. POHow to handle & return both properties AND functions missing in a Python class using the __getattr__ function?
      1. USsansjoe
    3. COOr just as good, return attribute not found for property requests, but handle function requests.
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      1. USsansjoe
 

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