How can I use UFCS for a loop

[Tim via Digitalmars-d-learn]

Hi all,

How can I change the following to a more D-like approach by using 
UFCS?

double[3] result;
Json json = res.readJson;
for(int i = 0; i < json.length; i++){
    result[i] = json[i].to!double;
}

I'd prefer to do something like:

result = res.readJson[].map!(to!double);