Pretty please: Named arguments

[Steven Schveighoffer]

On Mon, 28 Feb 2011 13:51:56 -0500, Jonathan M Davis <jmdavisProg at gmx.com>  
wrote:

> I'm not entirely against named arguments being in D, however I do think  
> that any
> functions that actually need them should be refactored anyway. So,  
> ultimately,
> I'm not sure that they're really all that useful. I'm sure that they'd  
> be useful
> upon occasion, but if you actually need them, then your function is  
> taking too
> many arguments.
>
> In actuality, if I were to vote on whether named arguments should be in  
> the
> language, I would definitely vote against it (I just plain don't want  
> the code
> clutter, and they strike me as a crutch to avoid writing functions with  
> good
> signatures in spite of their usefulness in some situations), but I can  
> see why
> some people might want them.

Although I am not strongly for named arguments, I think they would be a  
definite improvement.

Bearophile brought up one of the strongest cases for them:

foo(int width, int height) {}

Seems simple enough, I don't see how you have "too many arguments", but  
the call looks like this:

foo(123, 456);

So, looking at this call, can you tell which is width and which is  
height?  I've seen some libs that use width and height do height first  
also.  I usually have to go look up the API every time I'm reading/writing  
one of these.

But this is perfectly clear and resists API changes/differences:

foo(width: 123, height: 456);

The cool part about this is, named arguments are not required -- you can  
always just not use them.  But when you do use them, the code becomes much  
clearer.

-Steve