with builtins; let getColour = x: elemAt x __curPos.line;
getKey = x: elemAt x __curPos.line;

them = {
  first = {
    item = "banana";
    colour = "green";
  };

  second = {
    item = "frog";
    colour = "yellow";
  };
};

__findFile = _: k: with { v = split "/" k; }; them."${head v}"."${getKey v}";

in let {
  it = [
    <first/item>
    <second/colour>
  ];
  body = "could ${head it} be ${getColour it}?";
}