C++

[Sean Kelly]

David Medlock wrote:
> Its adherents rarely surprise me anymore.
> 
> Read my post on LTU and snk_kid's response:
> http://lambda-the-ultimate.org/node/1583#comment-19266
> 
> I am not trying to single him out, but the responses are pretty common 
> in my (arguably anectdotal) experience.
> 
> C++ is getting X in next version...
> Using boost/somelib we can do X...
> GC/Feature N will be great for C++ but for language Y its slow...
> 
> Sigh.
> 
> Its funny when people bring up libraries to make their points.

Not for C++.  For better or worse, a primary design goal of C++ was keep 
as much as possible out of the language definition by supporting user 
defined types that are indistinguishable from built-in types.  So a 
valid comparison to C++ must necessarily include what can be done in 
library code.

That said, I don't agree with many of snk_kid's observations.  D *does* 
support implicit template instantiation, for example.  The compiler 
implementation is just incomplete.  As for concepts, I do think they 
would be useful in D but I think they're less necessary than in C++ 
because D has static if and static assert.  Also, you can inherit from 
template type parameters as far as I know.

As for boost::function--it's a horrible bit of code and is far more 
awkward to use than delegates (particularly anonymous delegates) but it 
works pretty well aside from all that.  However, snk_kid doesn't address 
the idea that inner functions (ie. delegates) have access to local stack 
data, or that actually defining a new boost::function is nothing at all 
like defining a plain old function--it's obviously a class-based hack.

Meta logic is much the same... it's possible in C++ but is far more 
awkward.  And C++ obviously doesn't support strings or decimal numbers 
as template value parameters.  Not to mention aliases.

I think one problem is that some people just look at the spec to learn 
about the language, and the spec is quite sparse in places.  I don't 
think it mentions implicit template instantiation, and mention of some 
other features is hard to find.

> Walter you have your work cut out for you.
> Like most things in IT, the human/political issues outweigh the 
> technical ones.

Always.  But as long as D remains in development and isn't supplanted by 
some magic new language with all of D's features *and* a My Little Pony 
(tm) then it will have users.  Particularly with GDC available for the 
non-Windows folks.


Sean