Reducing template constraint verbosity? [was Re: Slides from my ACCU Silicon Valley talk]

[Jonathan M Davis]

On Wednesday, December 15, 2010 05:16:29 Steven Schveighoffer wrote:
> On Wed, 15 Dec 2010 04:34:53 -0500, Daniel Murphy
> 
> <yebblies at nospamgmail.com> wrote:
> > "Patrick Down" <pat at codemoon.com> wrote in message
> > news:ie8kei$1gdg$1 at digitalmars.com...
> > 
> >> Would it help to allow 'else' and 'else if' on the template constraints?
> >> 
> >> void foo(R)(R r) if(isRandomAccessRange!R)
> >> {...}
> >> else if(isInputRange!R)
> >> {...}
> >> 
> >> This could basically be translated into two specializations like this:
> >> 
> >> void foo(R)(R r) if(isRandomAccessRange!R) {...}
> >> void foo(R)(R r) if(isInputRange!R && !isRandomAccessRange!R) {...}
> > 
> > You can sorta already do this...
> > 
> > template foo(R)
> > {
> > 
> >     static if (isRandomAccessRange!R)
> >     
> >         foo(R r) {}
> >     
> >     else static if (isInputRange!R)
> >     
> >         foo(R r) {}
> >     
> >     else
> >     
> >         static assert(0, "R must be at least an input range");
> > 
> > }
> 
> The compiler doesn't treat this the same:
> 
> 1. no ifti
> 2. if no branches accept the R type, it tries another template.

By the way, what does IFTI stand for?

- Jonathan M Davis