Phobos - breaking existing code

[bearophile via Digitalmars-d]

weaselcat:

> On Sunday, 30 November 2014 at 23:16:14 UTC, bearophile wrote:
>> ...
>> I suggested to make that variable i an immutable by default.
>
> I suggest everything be made immutable by default ;)

Currently D doesn't have a keyword as "mut" or "mutable" so if 
you make the foreach variable immutable by default, you have some 
troubles when (rarely) you want a mutable foreach index (you need 
an auxiliary variable, and you have to type it manually, because 
if you use "auto" you get another immutable again).

But for the general case of all the variables, this breaks all 
the D2 code, so you can't do that (but I don't know why this 
change wasn't done in the D1->D2 transition), and I think Walter 
doesn't like things like pragma(strict) to be put beside the 
module name to denote modules where variables are const/immutable 
by default. So I didn't even discuss this impossible option.

Bye,
bearophile