Re: C# 7 Features - Tuples

[Lodovico Giaretta via Digitalmars-d]

On Monday, 5 September 2016 at 15:43:43 UTC, Nick Treleaven wrote:

Another solution is to support out argument declarations, as they are a more general feature. These could then be used as follows:

Tuple!(int, string) fn();
void unpack(T...)(Tuple!T, out T decls); // new phobos function

fn().unpack(int i, string s);

I think a combination of tuple slicing and unpack() overloads could allow ignoring leading or trailing tuple fields.

We can already (almost do that):

========================================================
import std.stdio, std.typecons;

void unpack(T...)(Tuple!T tup, out T decls)
{
        static if (tup.length > 0)
        {
                decls[0] = tup[0];
                tuple(tup[1..$]).unpack(decls[1..$]);
        }
}

void main()
{
        auto t = tuple(1, "a", 3.0);
        int i;
        string s;
        double d;
        t.unpack(i, s, d);
        writeln(i);
        writeln(s);
        writeln(d);
}
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