---
title: "alias vs alias_method"
description:
  "This blog discusses the differences between alias and alias_method in ruby."
canonical_url: "https://www.bigbinary.com/blog/alias-vs-alias-method"
markdown_url: "https://www.bigbinary.com/blog/alias-vs-alias-method.md"
---

# alias vs alias_method

This blog discusses the differences between alias and alias_method in ruby.

- Author: Neeraj Singh
- Published: January 8, 2012
- Categories: Ruby

It comes up very often. Should I use `alias` or `alias_method` . Let's take a
look at them in a bit detail.

## Usage of alias

```ruby
class User

  def full_name
    puts "Johnnie Walker"
  end

  alias name full_name
end

User.new.name #=>Johnnie Walker
```

## Usage of alias_method

```ruby
class User

  def full_name
    puts "Johnnie Walker"
  end

  alias_method :name, :full_name
end

User.new.name #=>Johnnie Walker
```

First difference you will notice is that in case of `alias_method` we need to
use a comma between the "new method name" and "old method name".

`alias_method` takes both symbols and strings as input. Following code would
also work.

```ruby
alias_method 'name', 'full_name'
```

That was easy. Now let's take a look at how scoping impacts usage of `alias` and
`alias_method` .

## Scoping with alias

```ruby
class User

  def full_name
    puts "Johnnie Walker"
  end

  def self.add_rename
    alias_method :name, :full_name
  end
end

class Developer < User
  def full_name
    puts "Geeky geek"
  end
  add_rename
end

Developer.new.name #=> 'Gekky geek'
```

In the above case method "name" picks the method "full_name" defined in
"Developer" class. Now let's try with `alias`.

```ruby
class User

  def full_name
    puts "Johnnie Walker"
  end

  def self.add_rename
    alias :name :full_name
  end
end

class Developer < User
  def full_name
    puts "Geeky geek"
  end
  add_rename
end

Developer.new.name #=> 'Johnnie Walker'
```

With the usage of `alias` the method "name" is not able to pick the method
"full_name" defined in `Developer`.

This is because `alias` is a keyword and it is lexically scoped. It means it
treats `self` as the value of `self` at the time the source code was read . In
contrast `alias_method` treats `self` as the value determined at the run time.

Overall my recommendation would be to use `alias_method`. Since `alias_method`
is a method defined in class `Module` it can be overridden later and it offers
more flexibility.

## Links

- [Human page](https://www.bigbinary.com/blog/alias-vs-alias-method)