mutable default parameter problem [Prothon]

[Christian Tismer]

Mark Hahn wrote:

...

> 2) Evaluate the default expression once at each call time when the default
> value is needed.  The default expression would be evaluated in the context
> of the function definition (like a closure).

> Comments?   How much Python code would these different proposals break?

I think not so very much.
The default mutable parameters have been abused to keep
class-like state. Default parameters in general have also been
used to speed up object lookup on certain speed contests.

Both usages are obsolete, since the same effect can be
achieved with a local function sitting in a scope,
from where it can use mutables it it needs to.

So I don't see many remaining advantages, and I think it is
a good idea to make the defaults less sticky.

+1 for 2)

ciao - chris

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