How would I override <=> for certain attributes of a class?
Say I have the following:
class Workout < ActiveRecord::Base # columns in db: time, weight, reps, distance end
I want to be able to sort by results, to list workouts by best time, weight, etc. But the ordering is different, because a low time is better than a high time, while a high weight is better than a low weight, etc.
Right now I'm doing a class method with an if statement like this:
def self.ranked_by(compare) if compare == :time find(:all).sort_by{|workout| workout.time}.reverse else find(:all).sort_by{|workout| workout.send(compare)} end end
That works, but it's ugly and the ugliness tends to replicate itself. I could simplify my code by overriding the <=> method for the time attribute so that I could simply do:
def self.ranked_by(compare) find(:all).sort_by{|workout| workout.send(compare)} end
But how to do that?