---
title: To self. or not to self.
teaser: How do you declare class methods in Ruby?
tags: web,ruby
author: Josh Clayton
published_on: 2009-09-11
---

![Et tu, Brute?]

[brute]: http://thoughtbot.widgetfinger.com/assets/48/original/caesar-brutus.jpg
  "Et tu, Brute?"

## Off with his head

Ruby developers have gone back and forth for ages as to whether to use `self.`
on their method calls.  Why is everyone bickering?  Can't we all just get along?

My guess is that we can't.

This argument is similar to that of the use of whitespace.  Some people are
picky while others are not; however, almost all have a very strong opinion.

## This above all: to thine own self be true

I prefer to qualify all public instance method calls with `self.`.  I'm one to
lean towards being explicit versus implicit, and `self.` helps me achieve this
goal.  This also makes coworkers (or any other individual reading the code)
aware of whether the method call is an attribute defined by ActiveRecord or a
public instance method on the class.  The reason this is an issue is because
local or block-level variables will never be prefixed with `self.` - it's much
easier on the eyes to be able to tell immediately whether you're dealing with
one or the other.

## Tempt not a desperate man

The explicitness of `self.` may be construed as line noise.  You may also be
asked why you don't use Hungarian notation.  Using `self.` isn't a naming
convention; it's defining the receiver of the message explicitly.  There's no
misconception and you're relaying intent very plainly by adding five characters.

## This is the long and short of it

```ruby
class User < ActiveRecord::Base
  before_save :sanitize_names

  def display_name
    return email if first_name.blank?
    [first_name, last_name].compact.join(" ")
  end

  protected

  def sanitize_names
    self.first_name = nil if first_name.blank?
    self.last_name = nil if last_name.blank?
  end
end
```

The result, after everything is said and done, would be:

```ruby
class User < ActiveRecord::Base
  before_save :sanitize_names

  def display_name
    return self.email if self.first_name.blank?
    [self.first_name, self.last_name].compact.join(" ")
  end

  protected

  def sanitize_names
    self.first_name = nil if self.first_name.blank?
    self.last_name = nil if self.last_name.blank?
  end
end
```

Although there may not me much of a different to the casual reader, the second
is, in my mind, worlds easier to comprehend.