From: SonOfLilit <sonoflilit@...>
Date: 2007-02-18T23:34:34+09:00
Subject: Re: Instance variable exists?

aur-sarafs-computer:~ aursaraf$ ri Object#instance_variable_get -T
------------------------------------------- Object#instance_variable_get
     instance_variable_get(ivarname)
------------------------------------------------------------------------
     (no description...)
aur-sarafs-computer:~ aursaraf$ ruby -v
ruby 1.8.5 (2006-12-04 patchlevel 2) [i686-darwin8.8.1]


On 2/18/07, George Ogata <george.ogata@gmail.com> wrote:
> Hi Detief, Aur,
>
> On 2/19/07, SonOfLilit <sonoflilit@gmail.com> wrote:
> > On 2/18/07, Detlef Reichl <detlef.reichl@gmx.org> wrote:
> > > Hi,
> > >
> > > what is the preferred way to see if an object already includes a
> > > instance variable?
> > >
> > > for now i do something like:
> > >
> > > @my_object.instance_variables.include? "var_name"
> > >
> > Hi,
> >
> > AFAIK it's the only way.
>
> There's also:
>
>   obj.instance_eval{defined?(@foo)}
>
> As you're hopefully aware, though, it's probably not particularly
> straightforward because it's discouraged in general.  Peeking at an
> object's instance variables is kinda intruding on its privacy.  There
> are some valid uses to be sure, but usually I think you're better off
> providing accessors for anything of interest outside the object.
>
> > Question: Why does Object#instance_varialbe_get have no documentation?
> > It's behaviour isn't that clear in cases like
>
> Where are you looking?  "ri instance_variable_get" gives me docs.
>
> Regards,
> George.
>
>