A nice way to step into 2012

[Don]

On 30.12.2011 07:36, Andrei Alexandrescu wrote:
> On 12/30/11 12:25 AM, Derek wrote:
>> On Fri, 30 Dec 2011 16:22:49 +1100, Don <nospam at nospam.com> wrote:
>>
>>
>>> Some names are better than others. But are they part of the API?
>>> That's the issue.
>>
>> Yes, that is an issue.
>>
>>> Often, parameter names (such as in sin(x)) are arbitrary and
>>> meaningless. This is fundamental: the parameter names are arbitrary in
>>> mathematics.
>>
>> Why is that? I just assumed that it was because mathematicians did a lot
>> of repetitive handwriting and thus brevity was important to them.
>
> Well one non-partisan opinion (in any direction) is I've recently played
> with e.g. Python's POpen
> (http://docs.python.org/library/subprocess.html#subprocess.Popen). It's
> quite comfy to be able to say stdout=somefile, stderr=somefile instead
> of enumerating arguments and relying on order to make them sensible.
>
> Using such functions is not math, but is part of writing programs.

There are definitely cases when you can create a much nicer API, when 
you can use named parameters. This is particularly true of flags, and 
where there are default parameters.
But I think that (a) it's not _all_ functions; and (b) you probably want 
to use named parameters consistently. I think it would be poor form to 
write these two lines in the same module:

  Popen(args, None, None, somefile, somefile);
  Popen(args, stdout : somefile, stderr : somefile);

so in the particular example of Popen, I think *requiring* all those 
parameters to be named in all calls wouldn't be a bad thing. Dunno if 
that's true in general though.

Note that in C/C++ you can easily create a header file where the 
parameters aren't named. But that isn't really available in D.
So there isn't even an opt-out mechanism.

I think: there are cases when named parameters are beneficial. There are 
cases where they are detrimental.
Is it possible to get the first, without the second, and without much 
complexity?
(I'm thinking of something like, a colon before the parameter name means 
the name is part of the API).