[Issue 5935] Non-tuple iteration with std.range.zip

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=5935


Lutger <lutger.blijdestijn at gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |lutger.blijdestijn at gmail.co
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--- Comment #5 from Lutger <lutger.blijdestijn at gmail.com> 2011-05-09 10:18:44 PDT ---
If no language changes for range iteration and tuple unpacking will be made,
perhaps it's worth to consider a generic wrapper for this purpose as a
compromise?

I couldn't think of a good name:

auto iterUntupled(R)(R input)
    if ( isInputRange!R &&
         is( typeof( { auto x = input.front.tupleof; }() ) ) )
{

    static struct IterUntupled(R)
    {
        this(R input)
        {
            _input = input;
        }

        int opApply( int delegate( ref typeof(_input.front.tupleof) ) dg )
        {
            while( !_input.empty)
            {
                auto front = _input.front;
                if ( auto result = dg(front.tupleof) )
                    return result;
                _input.popFront();
            }
            return 0;
        }

        R _input;
    }
    return IterUntupled!R(input);
}

This will also unpack arbitrary structs and classes, is that too loose?

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