From: Robert Klemme <shortcutter@...>
Date: 2007-05-22T22:00:13+09:00
Subject: Re: bug in ruby

On 22.05.2007 14:53, Brian Candler wrote:
> On Tue, May 22, 2007 at 09:41:03PM +0900, sairam MP wrote:
>> class Foo
>>   attr_accessor :bar
>>
>>
>>   def foo
>>     self.bar = 1
>>
>>
>>     if false
>>       bar = 2        # never executed
>>     end
>>
>>
>>     p self.bar       # prints 1
>>     p bar            # prints nil
>>   end
>> end
> 
> This is a bug in your understanding of the language, not in the language
> itself. You've not said exactly what you think it *should* do instead of
> what it does, so it's hard to give an answer tailored to improving your
> understandly.
> 
> But briefly: an assignment like "bar = 2" is seen at the time the program is
> *parsed* and means that an unqualified "bar" is treated as a local variable
> from that point onwards until the end of that scope. Whether or not it is
> actually *executed* makes no difference.
> 
> When you write "self.bar" or "self.bar=" you are explicitly making a method
> call to a method "bar" or "bar=" on the current object; this is never
> treated as a local variable.
> 
> If you write "bar" by itself, this is treated as a method call on the
> current object *unless* an assignment of the form "bar = x" has been seen by
> the parser earlier in the scope.

Additional reference material:

http://www.ruby-doc.org/docs/ProgrammingRuby/html/language.html#UO

Kind regards

	robert