Default Value

[Rick Johnson]

On Friday, June 21, 2013 8:54:50 PM UTC-5, MRAB wrote:
> On 22/06/2013 00:51, Rick Johnson wrote:
> > On Friday, June 21, 2013 5:49:51 PM UTC-5, MRAB wrote:
> > My argument has always been that mutables should not be
> > passed into subroutines as default arguments because bad
> > things can happen. [...] I also believe that a programmer
> > should not be prevented from passing mutable default
> > arguments [...]
> So, having mutables as default arguments is a bad idea,
> but a programmer should not be prevented from doing that,
> and a warning message should be printed on such occasions.

Well i'll admit that does sound like a contradiction.
Basically i meant, programmers should be *discouraged* from
passing mutables as default arguments but not *prevented*.
Of course, utilizing a stateless subroutine like i suggest,
argument mutability would not matter.

Sometimes when you're passionate about something your
explanations become so verbose as to render your idea lost
in the noise. Obviously i made that mistake here :)

In my last reply to Rotwang i explained the functionality i
seek to achieve in a set of three interactive examples.
Take a look at those and let me know what you think.

> > Why should i help the developers of this language. What have
> > they done for me?
> 
> They've developed this language, and provided it for free.
> They've even released the source code. You perceive flaws
> that you say must be fixed, but you're not going to help
> to fix them.

Agreed. And i am thankful for everyone's contributions. I
can be a bit harsh sometimes but my intention has always
been to improve Python.

> I _do_ want you to help to improve the language, and I
> don't care if you don't get it right first time. I didn't
> get it right first time when I worked on the regex module
> (I think that what I have on PyPI is my _third_ attempt!).

Well thanks for admitting you are not perfect. I know i am
not. We all had to start somewhere and anyone who believes
he knows everything is most assuredly a fool. Learning is
a perpetual process, same for software evolution.

> > You want to gain my respect? Then start engaging in honest
> > debates. Start admitting that yes, somethings about Python
> > are not only undesirable, they're just plain wrong.
> Python isn't perfect, but then no language is perfect.
> There will always be compromises, and the need to maintain
> backwards compatibility means that we're stuck with some
> "mis-features", but I think it's still worth using; I
> still much prefer it to other languages.

I understand. We can't break backwards compatibility for
everything, even breaking it for some large flaws could
cause a fatal abandonment of the language by long time
users. 

I just don't understand why i get so much hostility when i
present the flaws for discussion. Part of my intention is to
air the flaw, both for new users and old users, but a larger
intention is to discover the validity of my, or others,
possible solutions.

And even if that solution involves a fork, that is not a bad
thing. Creating a new fork and then garnering an acceptance
of the new spinoff would lead to at worse, a waste of time
and a huge learning experience, or at best, an evolution of
the language.

> > Stop calling me a troll when i am not. And not just me, stop
> > calling other people trolls too! Stop using the personal
> > attacks and straw man arguments.

Sorry. I failed to explain that this statement was meant not
directly for you but as a general statement to all members.
Sometimes i feel like my back is against the wall and i'm
fighting several foes at once. That can lead to me getting
defensive.