From: Brad Phelan <phelan@...>
Date: 2006-12-20T17:40:08+09:00
Subject: Re: Discovering the number of return arguments requested.


> 
> Actually it is not immediately GC'ed.  And when Ruby runs on a JVM then 
> short lived objects are definitively nothing to worry about.  Read here 
> for example:
> http://www-128.ibm.com/developerworks/library/j-jtp01274.html?ca=dnt-54
> 

Nice article. I remember reading stuff about Java and memory management
back in my Java programming days. The copying generation collector would 
work well with Ruby but does escape analysis work?

The Java example given in the article is

void doSomething() {
   Point p = someObject.getPosition();
   System.out.println("Object is at (" + p.x, + ", " + p.y + ")");
}

...

Point getPosition() {
   return new Point(myX, myY);
}

and the Ruby version would be

def do_something
    p = some_object.get_position
    puts "Object is at #{p.x}, #{p.y}"
end

The article makes the point that the optimizer can
surmise that p is thrown away because it is used only
to get it's attributes. However in Ruby p.x and p.y
are not public attributes but messages which could
result in absolutely anything happening with the
reference to the object in p.

One day I keep promising myself to peek inside the
Ruby interpreter and figure out how it all works. I
am sure that is where all the fun is at if I only
had the time.

Cheers

B