Re: Help me write "saveAll"

[Timon Gehr]

On 12/21/2012 06:01 PM, monarch_dodra wrote:

There are a lot of algorithms in std.algorithm that operate on
"foo(Range, Needles...)(Range range, Needles needles)".

Needles can be anything, in particular, either an "element" or a "range".

The thing is that every now and then, you want to save the entirety of
(the ranges) inside needles. EG, I want to be able to write:
foo(range, needles.saveAll);

I'm having trouble. I did two iterations:

//----
auto saveAll(Ranges...)(Ranges ranges) @property
{
     auto ret = ranges;
     foreach (Index, Type; Ranges)
         static if (isForwardRange!Type)
             ret[Index] = ranges[Index];
     return ret;
}
//----
This doesn't work, because: Error: functions cannot return a tuple
So that's that.
...

Use a phobos tuple?

return tuple(ret)

The caller can use .expand.