public Union4 <A, B, C, D> Select <A, B, C, D>(Func <I0, A> f0, Func <I1, B> f1, Func <I2, C> f2, Func <I3, D> f3) => Match(i0 => Union4 <A, B, C, D> .From0(f0(i0)), i1 => Union4 <A, B, C, D> .From1(f1(i1)), i2 => Union4 <A, B, C, D> .From2(f2(i2)), i3 => Union4 <A, B, C, D> .From3(f3(i3)));
public Union4 <II0, II1, II2, II3> Map <II0, II1, II2, II3>(Func <I0, II0> f0, Func <I1, II1> f1, Func <I2, II2> f2, Func <I3, II3> f3) =>
Match(
x => Union4 <II0, II1, II2, II3> .From0(f0(x)),
x => Union4 <II0, II1, II2, II3> .From1(f1(x)),
x => Union4 <II0, II1, II2, II3> .From2(f2(x)),
x => Union4 <II0, II1, II2, II3> .From3(f3(x)));