From: Pat Maddox <pergesu@...>
Date: 2006-05-09T06:24:51+09:00
Subject: Re: Question about instance_eval

On 5/8/06, Pat Maddox <pergesu@gmail.com> wrote:
> On 5/8/06, James Edward Gray II <james@grayproductions.net> wrote:
> > On May 8, 2006, at 3:30 PM, Pat Maddox wrote:
> >
> > > t.instance_eval { foo = 'foo' }
> >
> > Ruby will always see the above as a local variable declaration.
> > There is no way around that.
> >
> > > I also know that t.instance_eval { @foo => 'foo' } would work in this
> > > case.  However, I'm trying to set a Rails attribute, so I have to go
> > > through the method accessor.
> >
> > You've showed one way to handle it.  Another is the use
> > write_attribute(), if we are talking about ActiveRecord.
> >
> > James Edward Gray II
> >
> >
>
> Can I call pass in an object to instance_eval?  Let me show you the
> full class...
>
>
> class ScenarioGenerator
>   def initialize
>     @rules = []
>   end
>
>   def add_rule(&r)
>     @rules << r
>   end
>
>   def generate
>     s = Scenario.new
>     num_players = 0
>     @rules.each do |r|
>       r.call(s)
>     end
>
>     s.create_players(num_players) if num_players > 0
>     s
>   end
> end
>
> The reason I went to r.call(s) is so that I can do
> g = ScenarioGenerator.new
> g.add_rule { |s| s.sb = 200 }
>
> s then becomes the Scenario that I created.
>
> However I want to be able to modify num_players with a rule, so I need
> instance_eval.  I still need to be able to pass in the Scenario object
> though.  How could I do that?
>
> Pat
>
>

Apparently I can't do that, so I changed the design up a bit so that I
could do {|s| s.num_opponents = 3}.

Thanks for the help James and Justin, I really appreciate it.

Pat