From: matz@... (Yukihiro Matsumoto)
Date: 2001-01-29T17:54:33+09:00
Subject: [ruby-talk:10054] Re: difference between alias and alias_method

Hi,

In message "[ruby-talk:10053] difference between alias and alias_method"
    on 01/01/29, "Richard P. Groenewegen" <rpg@xs2all.net> writes:

|Is there a difference between these two pieces of code?  Is one of the
|two cheaper than the other?  
|
|        module Hello        |     module Hello
|          def hi            |       def hi
|            "hi"            |         "hi"
|          end               |       end
|          alias hello hi    |       alias_method :hello, :hi
|        end                 |     end               

alias is a statement, so that it's slightly faster than alias_method
which requires method lookup.

|What if hi was a very long and complicated piece of code, possibly
|taking up lots of memory?  Is this practical (given that hello will be
|a copy of hi), or is it better to say
|
|	def hello
|	  hi
|	end

this one has two differences.  (a) it does not protect `hello' from
redefinition of `hi'.  (b) it requires two method lookups.

							matz.