mapchain

[crazymonkyyy]

dlang/phobos#10808 (comment)

auto sumtypechain(Rs...)(Rs rs){
    //alias E=SumType!(staticMap!(ElementType,Rs));
    alias E=SumType!(NoDuplicates!(staticMap!(ElementType,Rs)));//snar this requirment is bad design
    return mapchain!(a=>E(a))(rs);
}

unittest{
    sumtypechain("abc",[1,2,3],iota(0,100),[13.37,4.20]).writeln;
}

combining ranges with an overloaded function that happen to return the same type if implemented at this abstraction level, trivializes the problem, where otherwise its a nightmare