import std.experimental.all;

​

void main()

{

    enum needles = [

        ["dub+", "RegistryPackageSupplier"],

        ["mvn+", "M2RegistryPackageSupplier"],

    ];

    string url = "mvn+";

    switch (url.startsWith(aliasSeqOf!(map!(a => a[0])(needles))))

    {

        foreach (uint i, el; aliasSeqOf!needles)

            case i + 1:

                mixin("writeln(`new " ~ el[1] ~ "(URL(url[" ~ el[0].length.to!string

                    ~ " .. $]))`); return;");

        default:

            "default".writeln;

    }

}