From: Tom Cloyd <tomcloyd@...>
Date: 2009-01-21T12:01:44+09:00
Subject: Re: cannot get attr_accessor to work

David A. Black wrote:
> Hi --
>
> On Wed, 21 Jan 2009, Tom Cloyd wrote:
>
>> David A. Black wrote:
>>> Hi --
>>>
>>> On Wed, 21 Jan 2009, Tom Cloyd wrote:
>>>
>>>> I've been staring at this for a couple of hours, and I cannot crack 
>>>> the nut. This SHOULD work, but I'm obviously screwing up. Just 
>>>> cannot see where. I'm carefully following several examples, but...I 
>>>> cannot get access to my instance variables.
>>>>
>>>> Here's a stripped down version of the code -
>>>>
>>>> # SetNet.rb
>>>>
>>>> def main
>>>> # Set up logging
>>>> run_log = Manage_log.new( 'logfile.txt' ).open
>>>> log = run_log.log
>>>> logging_now = run_log.lgg    # @logging_now = false
>>>
>>> I haven't read the rest of your code but I'll bet the problem is right
>>> there. Ruby is interpreting log and logging_now as local variables. If
>>> you want to call the methods of those names, you have to do:
>>>
>>>   self.log = run_log.log
>>>   self.logging_now = run_log.lgg
>>>
>>> Basically, given any expression that looks like this:
>>>
>>>    var = value
>>>
>>> the parser interprets var as a local variable name. So you have to add
>>> the explicit receiver to achieve the method call.
>>>
>>>
>>> David
>>>
>> David,
>>
>> Thank for your reply, but I'm puzzled by it. Doesn't the code in my 
>> previous post make it clear that I'm dealing with instance variables? 
>> The class instance initiates them, e.g., @log, and I'm trying to get 
>> that with the run_log.log call. This is NOT an attempt to call a 
>> method. I very carefully copied (I thought) the pattern I saw in 
>> several authoritative sources, but it doesn't work for me, which is 
>> nuts.
>>
>> I hope this makes sense.
>
> The code I saw was:
>
>>>> run_log = Manage_log.new( 'logfile.txt' ).open
>>>> log = run_log.log
>>>> logging_now = run_log.lgg    # @logging_now = false
>
> which are local variable assignments, and you'd mentioned
> attr_accessor, so I assumed you had attr_accessor somewhere in a part
> of the code you hadn't posted. It's a common error to do:
>
>   class C
>     attr_accessor :name
>     def initialize(name)
>       name = name        # should be @name or self.name
>     end
>   end
>
> so I surmised that that was what was going on. Oh well -- can't hurt
> to see that particular potential problem anyway :-)
>
> I'm still not sure where attr_accessor fits in.
>
>
> David
>
Sorry you got a partial copy of the code I sent. It rather sounded like 
that was what happened. I DO appreciate that you responded so quickly.  
You've certainly been very helpful to me on a number of occasions. (And 
I require that help, at times, if I'm get anything much accomplished in 
Ruby, in the time I have!).

Thanks.

Tom

-- 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tom Cloyd, MS MA, LMHC - Private practice Psychotherapist
Bellingham, Washington, U.S.A: (360) 920-1226
<< tc@tomcloyd.com >> (email)
<< TomCloyd.com >> (website) 
<< sleightmind.wordpress.com >> (mental health weblog)
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