Re: [Rails] why do I have to refer to my attr_accessible as self.varname?

On Dec 21, 2012, at 12:37 PM, Dan Brooking wrote:

> I posted a previous message about overriding initialize... because I was having issues setting some of the parameters. I have a Page model that has:
>
> attr_accessible :url, :title, :doc, :domain
>
> and it's called via:
>
> Page.new(:url => 'http://www.yahoo.com')
>
> Since I'm only passing in the url to new, I needed to set the other parameters. I was trying to do this via an after_initialize callback which wasn't working so tried overriding initialize... still not working.
>
> What I found out was that in my after_initialize, I was referring to title as @title which is why it was not working. I switched it to self.title and it works fine.
>
> My question is - why?

@title is an instance variable. Until you set it, it doesn't exist. Having a method on the model called title (or an accessor, or some other Rails magick) does not instantiate that method's return until and unless you ask for it by calling the method. Calling self.method_name just makes it clear which same-named method you really mean. Self is implied much of the time, but when you have all the many method_missing options available, it might not be the first one such that gets called.

Walter

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