shouting versus dotting

[Jason House]

Andrei Alexandrescu Wrote:

> Jarrett Billingsley wrote:
> > On Sun, Oct 5, 2008 at 12:06 AM, Andrei Alexandrescu
> > <SeeWebsiteForEmail at erdani.org> wrote:
> >> 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.
> >>
> >> That's why I find the choice of "!" poor. I believe it can impede to some
> >> extent acquisition of templates by newcomers, and conversely I believe that
> >> using .() can make templates more palatable. I tried using ".()" in my code
> >> and in only a couple of days it looked and felt way better to me. Based on
> >> that experience, I suggest that "!()" is dropped in favor of ".()" for
> >> template instantiation for D2.
> >>
> >> Sean's argument that "The exclamation mark signifies an assertion of sorts"
> >> is exactly where I'd want templates not to be: they should be blended in,
> >> not a hiccup from normal code. Serious effort has been, and still is, made
> >> in D to avoid shell-shocking people about use of templates, and I think
> >> ".()" would be a good step in that direction.
> > 
> > Long argument short:  I don't mind !() at all, and changing it to .()
> > seems like a pointless pedanticism.  But since you're the one
> > suggesting it, there's a very good chance of it getting into the
> > language (if it hasn't already), so there's not much use arguing
> > against it.
> 
> It won't make it unless others try it and find it palatable too. But 
> please let's try it first.
> 
> Also, I'm much less keen on introducing .() than on ousting !(), which I 
> believe was a very poor choice. So I suggest we all explore other syntax 
> choices until we find something that we can show to the world with a 
> straight face.
> 
> 
> Andrei

I have no trouble telling the world about !(). It's simple and clean. In fact, I already have told C++ folk about it when contrasting to <>.

If I had to enumerate popular choices in the order of my preferences:

1. {}
2. !()
3. :()
4. .()

The large advantage of {} is that it's a single character. 

!() has precedent going for it. IMHO, deeply nested !() should use alias statements just like deeply nested () should.

:() is about as good as !() except for ambiguity with the archaic ?: syntax and labels.

.() is just strange. It looks like template code trying to look like normal code... Kind of like how I hate manifest constants looking like enums.