From: David Masover <ninja@...>
Date: 2009-03-04T20:47:07+09:00
Subject: Re: Compiling a Ruby app

Rick DeNatale wrote:
> On Tue, Mar 3, 2009 at 5:09 AM, David Masover <ninja@slaphack.com> wrote:
>
>   
>> Sharagoz -- wrote:
>>
>>     
>>> My second concern is protecting source code.
>>> I realize that everything that can be compiled can also be decompiled,
>>>
>>>
>>>       
>> That is not entirely true. Or rather, it can be "decompiled", all right,
>> but not into anything resembling the original source code.
>>     
>
>
> Actually closer than you might think:
>
> require 'rubygems'
> require 'ruby2ruby'
>   

I was speaking of compiled languages in general. As a trivial example, a 
common C optimization is to inline functions which are below a certain 
size. Now, when decompiling, how do I know what was inlined, and what 
really should be duplicate code?

Oh, and not all compiled versions preserve debugging symbols, meaning 
any code that isn't actually part of an external API is likely 
completely without comments, variable names, method names, etc...

Now, Ruby tends to be much more dynamic, meaning less of the code can be 
discarded by the compiler. But that doesn't mean it will look like you 
expect. For example:

class Foo
  %w(one two three four five).each_with_index do |name, index|
    define_method(name) { index + 1 }
  end
end

puts Ruby2Ruby.translate Foo

produces:

class Foo < 
Object                                                             
  def 
five                                                                     
    (index + 
1)                                                                
  
end                                                                           


  def four
    (index + 1)
  end

  def one
    (index + 1)
  end

  def three
    (index + 1)
  end

  def two
    (index + 1)
  end
end

Completely out of order, I have no idea what "index" means in that 
context, and it only bears a vague resemblance to the source code used.