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Comment by xmodem | Hacker News Reader

  def sanity
    @sanity
  end

  def sanity=(val)
    @sanity = val
  end

how are those six lines not boilerplate?

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They are. (And generated behind the scenes by "attr_accessor :sanity", if you'd prefer the short version.)

The benefit everything-is-a-message is that you can swap out the implementation of sanity (or sanity=) if needed, eg.

Before:

  attr_accessor :radius, :diameter

After:

  # Refactored radius to be the new source of truth.
  def diameter
    radius * 2
  end
  
  def diameter=(val)
    self.radius = val / 2
  end

In PHP (for example), MyClass->diameter and MyClass->diameter() are completely different things. Any existing code (including code you don't control) needs updating to change references from the former to the latter when moving logic into something that was previously static.

This article is flawed by holding up those six lines in themselves as something great, but I think the point the author is trying to get across is valid.

I suppose the author was trying to be explicit for the sake of a reader unfamiliar with Ruby. The typical way to avoid that boilerplate is by using 'attr_accessor :sanity', which defines those getter and setter methods (and it is possible to implement attr_accessor or similar directly in Ruby, should you need more boilerplate-reducing helpers).

This is exactly it. I would commonly use the shorthand for something like this, but I felt that it would only deter from the point I was illustrating, which is that a couple methods can seamlessly act like a variable.

They are, which is why Ruby's Module (class comes from module) has attr_accessor method.

http://ruby-doc.org/core-1.9.3/Module.html#method-i-attr_acc...

The above can be written as

  attr_accessor :sanity

I believe it'd be idiomatic to use

  attr_accessor :sanity

  def initialize
    @sanity = 0
  end

On that note I like Go's default values for primitive types. An int sanity would be zero by default.

Edit: seeing five simultaneous posts saying the same thing makes me feel trolled a bit :)

Nah, Rails devs are just really excited to finally have their chance to shine in the HN comments ;)

You might want to participate in https://bugs.ruby-lang.org/issues/8564

  attr_accessor :sanity

Would be a neater way to write this.

  attr_accessor :sanity

attr_accessor :sanity

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