From: Jim Weirich <jweirich@...>
Date: 2003-06-01T06:36:53+09:00
Subject: Re: newbie questions

On Sat, 2003-05-31 at 16:45, Steven Ketcham wrote:
> I am probably confusing concepts but in C++ you can pass a parameter by reference, pointer or value. Copy constructors, 
> variable scope and  things like that are very important to track. If I pass a complex object by value to a function, the copy 
> of the object will automatically run it's destructor  when the function
> returns. This could be devasting when working with file or database handles.
> 
> How are objects handled when passed to a function with Ruby?

You have a "shoebox" mentally.  In other words, you are thinking of
variables as "showboxes" in which you put values.  This mental model
works well with C++, where a constructor is run when a shoebox
(variable) is created and a destructor is run when the shoebox is
destroyed.  Copy contructors and assigment operators all deal with the
coping of the contents of one shoebox to another.

When dealing with Ruby, forget shoeboxes.  Variables are names that are
attached (bound) to values.  Names can be rebound at will and multiple
names can be bound to any one object.

See http://www.rubygarden.org/ruby?VariablesAndObjects for a longer rant
on this topic.

-- 
-- Jim Weirich     jweirich@one.net    http://jimweirich.umlcoop.net
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"Beware of bugs in the above code; I have only proved it correct, 
not tried it." -- Donald Knuth (in a memo to Peter van Emde Boas)