Question

I have a few places in my code where I have nested objects, but can’t guarantee they will always be set.

This could give me an ruby undefined method for nil:NilClass

puts obj1.obj2.obj3.obj4.to_s

This check is ugly and repetitive:

if(obj1 && obj1.obj2 && obj1.obj2.obj3 && obj1.obj2.obj3.obj4)
  puts obj1.obj2.obj3.obj4.to_s
end

Is there a concise way to write, if anything is nil just silently fail?

Answer 1

My version of try:

class Object
  def try(*args, &block)
    if args.empty? and block_given?
      begin
        instance_eval &block
      rescue NameError => e
        puts e.message + ' ' + e.backtrace.first
      end
    elsif respond_to?(args.first)
      send(*args, &block)
    end
  end
end

So then instead of this long expression:

obj1.try(:obj2).try(:obj3).try(:obj4).to_s

you can do this:

obj1.try{ obj2.obj3.obj4.to_s }

UPDATE:
Made it a little cleaner