Flag proposal

[Lars T. Kyllingstad]

On Fri, 10 Jun 2011 18:16:14 -0500, Andrei Alexandrescu wrote:

> On 6/10/11 6:03 PM, Dmitry Olshansky wrote:
>> On 11.06.2011 0:58, Andrei Alexandrescu wrote:
>>> On 6/10/11 3:30 PM, Nick Sabalausky wrote:
>>>> I really see Flag more as a way to try to rationalize avoiding adding
>>>> named
>>>> parameters to the language.
>>>
>>> There are fights that I believe are important and others that I think
>>> are less so. I find name parameters nice to have but more in the
>>> second category. There's just so much stuff that's more important.
>>>
>>>> And yes, the legibility of "foo(Flag!"param".yes,
>>>> Flag!"otherParam".no);",
>>>
>>> Fair point. I figured this should be easier:
>>>
>>> foo(yes!"param", no!"otherParam");
>>
>> I think this looks not half bad and does not require change in the
>> language.
>> Still yes.param and no.param might be easier on the eyes, though IMO it
>> should look more like just param and no.param. e.g.
>> StopWatch(autoStart);
>> StopWatch(no!autoStart); // or no.autoStart
> 
> Ask, and ye shall receive.
> 
> https://github.com/andralex/phobos/
commit/801ccc96ce56827cd0d0b608895269bdccba4330

I'm sold. :)

To add my 2 cents to the "named arguments" debate, I can't believe people 
are still asking for this.  At this point in D's development, adding such 
would be a major language change, and there really shouldn't be any more 
of those.  I mean, D2 supposedly went stable almost a year ago!  If/when 
work starts on D3, we can get back to it.

In the mean time, I think Flag!"param" with the new Yes/No types nicely 
solves a common case of code duplication in Phobos.  It is not, nor do I 
think Andrei intended it to be, a general attempt to emulate named 
parameters.

-Lars