OutputRange should be infinite?

[Johannes Pfau]

Am Fri, 05 Oct 2012 17:15:44 +0200
schrieb "monarch_dodra" <monarchdodra at gmail.com>:

> A good while ago, I ran into some issues regarding output ranges. 
> (reference 
> http://forum.dlang.org/thread/xyvnifnetythvrhtcexm@forum.dlang.org)
> 
> The gist of the problem is that with "put" an OutputRange that 
> accepts a T will accept a Range!T, and a Range(Range!T) and a 
> Range!(Range(Range!T)) add infinitum.
> 
> This all works nice and well, provided the output range does not 
> ever become empty => is infinite. However, this is currently not 
> the case, and this code will blow in your face:
> 
> //--------
> auto a = new int[](1);
> auto b = new int[](2);
> assert(isOutputRange!(typeof(a), typeof(b)));
> if(!a.empty)
>     put(a, b); //Nope
> //--------
> auto a = new int[](10);
> auto b = new int[][](3, 5);
> assert(isOutputRange!(typeof(a), typeof(b)));
> if(a.length > b.length)
>      put(a, b); //Nope
> //--------

Couldn't we just fix std.range.put to check for an 'empty' property?