Reasoning behind 'self' parameter in classes?

[Robert Dailey]

On Wed, Jul 30, 2008 at 2:48 PM, Patrick Mullen <saluk64007 at gmail.com>wrote:

> Well, the linked thread gives many reasons, but as mentioned it is a
> flamewar thread.  Philosophically python is not an "object oriented"
> language per say, it has an object system, a not bolted on one I might add,
> but it doesn't force developers to use that methodology.  You can be
> functional or procedural if you'd rather.  Following this philosophy, when
> methods were designed, they were merely functions that got passed an
> instance as the first argument.  The parser followed this design choice.  As
> far as I understand it, the underlying method object is not different from a
> function argument, thus it cannot have any magic arguments built in.  The
> only magic involved is the fact that the object, when calling a method, will
> pass its instance as the first argument.
>
> I don't believe there is any chance of this changing in python 3, python 4
> is anyone's guess...
>
> This does allow some good things that come for free, like adding methods
> later, or changing functions into methods or methods into functions.  If you
> start out developing a class, but feel a class is too bulky, you can delete
> the "class" line, dedent the methods, and have a set of functions instead
> for free.  Or, if you have functions that are set up to take instances as
> their first argument already, you can bundle them up into a class very
> easily.
>
> If by "hack" you mean using features already available in the language to
> accomplish things, that kind of is what it is, and that's kind of what
> python is about.  New syntax for a new feature is uncommon, but it happens.
> New syntax that breaks old code is very uncommon, and is only now coming out
> in python 3.  And the biggest change in python 3 is to eliminate added
> syntax, such as print being a statement, and make the code reuse more python
> features rather than have every feature exist as an island.  Print being a
> function, for instance, lets you use the same syntax for it that you use for
> other functions, making everything clearer and more unified.  A common thing
> programmers might do when upgrading their code is to turn print statements
> into better logging functions - if print was a function in the first place
> this would be an easier task.
>
> Eliminating self doesn't accomplish much, and changes of this nature just
> don't get done without a good reason.  It takes away something that might be
> annoying, but doesn't add anything.  The benefits of changing have to be
> significant for a code change to break the existing syntax.  Many people are
> upset even about some of the changes in python 3, that the benefits don't
> outweight the cost of change, and most of those changes are less damaging
> than playing around with the self businss would be :)
>
> So no, self not a mysterious thing that we should never question.  Self is
> an understood thing that has been questioned very often (weekly, monthly)
> for many many years - there are not enough good reasons to bother with
> changing it, and there enough good reasons for it that it's best to keep it.
>

This is quite possibly the best explanation yet. Thank you very much for
this. You bring much insight into the feature.

You see, a lot of people I've worked with have complained about the 'self'
parameter. While this has never bothered me personally, other people find it
a "flaw in the language". I often argue with my coworkers that Python is
better than Ruby (This is of course opinionated and biased), but sometimes I
find I cannot defend python when I need to, and in the argument of 'self' I
find that to be one of those situations.

Anyway, I appreciate everyone taking the time to explain this to me. I'm
sure you guys are at the point of copy/paste of your responses on these
topics :) They're far too frequent it seems. In any case, I still appreciate
the responses. This topic can die now, I would hate to see it continue and
another flame war to start.
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