From: Chris Irish <chris.irish@...>
Date: 2005-12-03T05:38:41+09:00
Subject: Re: Make a symbol represent a method?

Jacob Fugal wrote:

>On 12/2/05, Chris Irish <chris.irish@libertydistribution.com> wrote:
>  
>
>>I just read a FAQ page online about Ruby symbols and someone mentions this
>>
>>Also, the entirely realistic reasoning for using symbols: If you
>>are going to refer to a method name, use a symbol. Because by
>>defining the method, the symbol exists anyway.
>>
>>Can someone show me an example of this?  Is this referring to the method
>>of a class?
>>    
>>
>
>It simply comes down to this. When you define a method the method
>definition is saved away and connected to a lookup table for the
>object you defined the message on. The key into that lookup table? A
>symbol representing the method's name. So if I define:
>
>  def hello
>    puts "Hello, world!"
>  end
>
>The body is complied into a Method object, and that Method object is
>then attached to the current self (Kernel, is you're not in anything
>else) with the symbol :hello as the key. After defining the above, try
>this:
>
>  send(:hello)
>
>Anytime you make a method call, it's essentially just an invocation of
>send with the method name and arguments as paramenters. (Well, it's a
>little more complicated, but that's why I said "essentially".)
>
>Anyways, the point of the quote from the FAQ is that just be defining
>the method hello, the symbol :hello already exists, since it's used to
>index the receiver's method table. So, if you're going to be passing
>the method name around (common with metaprogramming), you save by
>using the already existing :hello symbol, instead of creating a new
>"hello" String object.
>
>I hope that makes sense...
>
>Jacob Fugal
>
>  
>
K.... I get it
One more thing, Can I use the symbol to call a method and pass arguments 
to it?  Or is it just a reference to the methods name so that's not 
possible?