C++ guys hate static_if?

[deadalnix]

On Thursday, 14 March 2013 at 23:52:59 UTC, Nick Sabalausky wrote:
> On Thu, 14 Mar 2013 17:54:52 -0400
> Andrei Alexandrescu <SeeWebsiteForEmail at erdani.org> wrote:
>>
>> it's not like we claim to support input ranges and
>> then call .save against them.
>
> Although this is getting OT, we do kind of do that in a way:
>
> It's very common for a range to be a struct rather than a 
> class. In
> fact, std.range/algorithm has generally been considered to work
> better with struct ranges with class ranges being a secondary 
> thought.
>
> And yet, due the the nature of structs, all it takes to 
> effectively
> ".save" an InputRange (or at least attempt to) is this:
>
> struct MyInputRange {...}
> void foo(R)(R r) if(isInputRange!R) {
>     auto s = r;
> }
> ...
> foo(MyInputRange());
>
> That implicitly does the equivalent of ".save" on a mere 
> InputRange
> *twice*. The result, of course, is completely dependent on the 
> input
> range in question.

Passing range by value is completely undefined, which is IMO a 
big weak spot of ranges.