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Comment by nopal | Hacker News Reader

I'm sure it does, but I can write the same class in C# just as easily:

    class Person
    {
        public int Sanity { get; set; }
    
        public Person()
        {
            Sanity = 50;
        }
    }

And to call it:

    var programmer = new Person();
    programmer.Sanity += 1000000;
    Console.WriteLine(programmer.Sanity);

I don't see much difference between Person.new and new Person();.

What are the real ways in which it will knock my socks off? I'm honestly asking. Even though I program C# at work, I'm very interested in the advantages of other languages.

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Getters and setters that have no logic are pointless. In Go I would write:

    type Person struct {
        Sanity int
    }
    
    func NewPerson() *Person {
        return &Person{Sanity: 50}
    }

This is good enough 90% of the time (and faster), but if I was writing a library package and I wanted to care about protecting with some logic and care about my export signature:

    type Person interface {
    	Sanity()
    	SetSanity(val int)
    }
    
    type person struct {
    	sanity int
    }
    
    func NewPerson() Person {
        return &person{sanity: 50}
    }
    
    func (p *person) Sanity() {
    	return p.sanity
    }
    
    func (p *person) SetSanity(val int) {
    	if val > SOME_FOO1 && val < SOME_FOO2 {
    		p.sanity = val	
    	}
    }

And with C# 4 dynamics you can even pull off that method_missing routine.

Same with Scala - http://eranation.roughdraft.io/5962848

Ruby really is a great language. The author just posted a poor example that is frankly NOT idiomatic Ruby. The proper way to create a getter and setter method on an instance variable is like so:

  class Person
    attr_accessor :sanity

    def initialize
      @sanity = 50
    end
  end

All the attr_* class methods do is define precisely the instance methods the author wrote by hand. Indeed, if attr_reader, attr_writer, and attr_accessor weren't part of Ruby's Module class you could write them yourself, like so: https://gist.github.com/jfarmer/6b4deeb8bcfbe030f876

If using an "eval" method seems smelly to you, you can achieve the same result in pure Ruby using define_method, instance_exec, and instance_variable_get. There are good practical reasons to use module_eval, though.

Regardless, I think the author's point was more that there's nothing "special" about getters and setters in Ruby. They're just plain ol' methods. As a class of methods we write them often enough that we've also defined a higher-order method that takes an instance variable name as input and dynamically defines those getters and setters on the underlying object.

We wouldn't "lose" anything by not having attr_reader and friends, though. Our code would just be slightly more verbose.

>Regardless, I think the author's point was more that there's nothing "special" about getters and setters in Ruby. They're just plain ol' methods.

Ah, that's a good point. That seems to be a more accurate interpretation of what the author was trying to express.

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