shouting versus dotting

[Chris R. Miller]

Ary Borenszweig wrote:
> Andrei Alexandrescu escribió:
>> The problem I see with "!" as a template instantiation is not 
>> technical. I write a fair amount of templated code and over years the 
>> "!" did not grow on me at all. I was time and again consoled by Walter 
>> than one day that will happen, but it never did. I also realized that 
>> Walter didn't see a problem with it because he writes only little 
>> template code.
>>
>> I didn't have much beef with other oddities unique to D. For example, 
>> I found no problem accommodating binary "~" and I was wondering what 
>> makes "!" different. I was just looking at a page full of templates 
>> and it looked like crap.
>>
>> One morning I woke up with the sudden realization of what the problem 
>> was: the shouting.
>>
>> In C, "!" is used as a unary operator. That may seem odd at first, but 
>> it nevers follows a word so it's tenuous to associate it with the 
>> natural language "!". In D, binary "!" _always_ follows a word, a 
>> name, something coming from natural language. So the conotation with 
>> exclamation jumps at you.
> 
> I was thinking about in which other way templates could be specified... 
> Most of the other symbols already have a meaning as binary operator. And 
> it also would be nice to have an opening and closing symbols, like <> in 
> Java, C++, etc.

I remember reading that Walter specifically rejected that idea because 
it became ambiguous with bitshift operations.  In my time with Java, I 
saw many of these:

public class Foo<Bar<o extends ArrayList>> { ... }

When instantiated in code the >> at the end of the template declaration 
does become very ambiguous with a bitshift.

> Can't {} be used for that? For example:
> 
> List{int} someList;
> 
> void foo{T}(T val) {
> }
> 
> It seems more quiet. :-)

I rejected that idea when I was searching for counterproposals because 
it conflicts with the code-block syntax.  The existing () is much less 
ambiguous, since when you encounter two sets of parenthesis it must be a 
template.  If it were multiplication it would require the explicit * 
binary operator.

The !() syntax seems to serve only as a heads up that it's a template. 
Otherwise (as far as I can tell) a simple foo(int)(bar, baaz) would work 
just as well as foo!(int)(bar, baaz).