dropping parentheses on template instantiation

[Ary Borenszweig]

Andrei Alexandrescu escribió:
> Denis Koroskin wrote:
>> On Sun, 05 Oct 2008 22:18:26 +0400, Andrei Alexandrescu 
>> <SeeWebsiteForEmail at erdani.org> wrote:
>>
>>> I just realized something different. After making an informal review 
>>> of some code, I saw that a large percentage of template 
>>> instantiations only need ONE argument.
>>>
>>> This makes me think, with the old "!" notation, parentheses could be 
>>> dropped entirely without prejudice:
>>>
>>> auto covariance = Matrix!real(n, n);
>>> auto normalized = SparseVector!double(n);
>>>
>>> and so on.
>>>
>>> To the unbridled joy of the enemies of the Sad Pirate, the dot won't 
>>> work for template instantiation because without the parentheses it 
>>> DOES engender ambiguity.
>>>
>>> Now say we take the following route:
>>>
>>> 1) We find something different from shouting
>>>
>>> 2) We drop the parentheses for 1 argument
>>>
>>> That sounds like a possible winner. In this case the "#" becomes 
>>> considerably more attractive, in fact very attractive exactly because 
>>> it looks unlike any letter:
>>>
>>> auto covariance = Matrix#real(n, n);
>>> auto normalized = SparseVector#double(n);
>>>
>>> Ideas?
>>>
>>>
>>> Andrei
>>>
>>> P.S. The Sad Pirate is the emoticon
>>>
>>> .(
>>>
>>> It doesn't have an eye and is sad, too.
>>
>> Just to clarify things: Do you propose moving the first template 
>> argument outside of the parentheses *or* ditching them iff there is 
>> only one parameter? I mean, what does the original code look like, 
>> because there is ambiguaty in your statement (to me):
> 
> Ditch parens if there's only one argument. In that case the extra 
> character becomes an enabling asset, not a liability.
> 
>> const int n = 42;
>> auto covariance = Matrix!(real, n, n); <-> auto covariance = 
>> Matrix#real(n,n);
>>
>> *or*
>>
>> auto covariance = Matrix!(real)(n, n); <-> auto covariance = 
>> Matrix#real(n,n);
> 
> The latter.
> 
>> Other than that Vector at real or Vector#real both sound good!
> 
> I agree. In fact "Vector at real" sounds like a good way of talking 
> about templates instead of "Vector instantiated with real". One reason 
> for which I think "this" is a poor choice (as opposed to e.g. "self") is 
> that it's very hard to talk about it.

I like Vector at real. Also: HashMap@(Key, Value) looks nice to me. The 
only thing is that in spanish keboards, I have to do alt-gr + Q to get 
one @ :-P