shouting versus dotting

dsimcha dsimcha at yahoo.com
Sat Oct 4 21:25:03 PDT 2008


== Quote from Andrei Alexandrescu (SeeWebsiteForEmail at erdani.org)'s article
> 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.
> Andrei

Personally, I think that ".()" looks a little too much like a normal
function/method call.  The "!()" syntax looks just different enough to make it
easy to keep straight in my head that stuff with the "!" is a compile-time
construct and stuff without it can be evaluated at runtime.



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