Nested ternary/conditional operator does not work?

I have a .jsx script that works well until it reaches this line:

return arguments.length === 1 ? r instanceof rgb ? rbg(r.r, r.g, r.b) : rgb_parse() : rgb(r, g, b);

The code is valid JavaScript but does not run in the ExtendScript Toolkit. Do I have to replace all of these blocks with if/else statements or is there another solution?