DIP6: Attributes

[Denis Koroskin]

On Wed, 05 Aug 2009 07:20:38 +0400, Benji Smith <dlanguage at benjismith.net>  
wrote:

> Frank Benoit wrote:
>> Andrei Alexandrescu schrieb:
>>> Ary Borenszweig wrote:
>>>> call!(foo)(5, "hello")
>>>>
>>>> with varaidic args?
>>> Well some don't like to need to remember the order of arguments.
>>>
>>> Andrei
>>  Assigning the argument by name instead of order has two other benefits,
>> i can think of...
>> 1. on the call side, it is documented for what the given values are  
>> used.
>> 2. it may be possible to let all parameters have default values and for
>> example just give a value for the last parameter. This is not possible
>> with just the parameter order.
>
> But these aren't issues with reflection. These are just the same  
> function calling rules applied elsewhere in the language:
>
> 1) If you want to call a function: you must know its name.
>
> 2) If you want to pass parameters: you must know the correct order.
>
> I can't imagine a circumstance where someone uses reflection to call a  
> function and knows how to create the correct set of arguments, but  
> doesn't know what order to put them in.
>
> --benji


They are mostly used with optional parameters:

void foo(int x = -1, int y = 42, bool b = false);

foo(b: true);