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To: python-list@python.org
From: Mark Lawrence <breamoreboy@yahoo.co.uk>
Subject: Re: Building CPython
Date: Sat, 16 May 2015 00:27:58 +0100
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Xref: csiph.com comp.lang.python:90697

On 15/05/2015 23:44, Marko Rauhamaa wrote:
> BartC <bc@freeuk.com>:
>
>> What /is/ a method lookup? Is it when you have this:
>>
>>   A.B()
>>
>> and need to find whether the expression A (or its class or type) has a
>> name B associated with it? (And it then needs to check whether B is
>> something that can be called.)
>>
>> If so, does that have to be done using Python's Dict mechanism? (Ie.
>> searching for a key 'B' by name and seeing if the object associated
>> with it is a method. That does not sound efficient.)
>
> That is a general feature among high-level programming languages. In
> Python, it is even more complicated:
>
>   * first the object's dict is looked up for the method name
>
>   * if the method is not found (it usually isn't), the dict of the
>     object's class is consulted
>
>   * if the method is found (it usually is), a function object is
>     instantiated that delegates to the class's method and embeds a "self"
>     reference to the object to the call
>
> IOW, two dict lookups plus an object construction for each method call.
>
>
> Marko
>

As a picture paints a thousand words is anybody aware of a site or sites 
that show this diagramatically, as I think I and possibly others would 
find it far easier to grasp.

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence