From: Ed Sinjiashvili <edsin@...>
Date: 2002-06-03T13:44:59+09:00
Subject: Re: $a = 5; $b = 'a'; print $$b

Philip Mak <pmak@animeglobe.com> writes:

> And can this be done with instance variables? I'm trying to do this:
> 
> class Series
>     attr_accessor :sid, :handle, :name
>     def initialize(vals) 
>         vals.each_key { |key|
>             @(key) = vals[key] # This doesn't work; syntax error
>         }   
>     end
> end
This particular case can be rewritten either with instance_eval or
method_missing. Which is less evil is up to you.

% cat series_eval.rb
class Series
  attr_accessor :sid, :handle, :name
  def initialize(vals)
    vals.each_key { |key|
      instance_eval "@#{key} = vals[key]"
    }
  end
end

s = Series.new({"sid" => 3, "handle" => "smoon", "name" => "Sailor Moon"})
puts s.name # should print "Sailor Moon"
% 

% ruby series_eval.rb
Sailor Moon

% cat series_missing.rb
class Series
  def initialize(vals)
    @vals = vals
  end

  def method_missing (symbol, *args)
    @vals[symbol.to_s]
  end
end

s = Series.new({"sid" => 3, "handle" => "smoon", "name" => "Sailor Moon"})
puts s.name # should print "Sailor Moon"
%

% ruby series_missing.rb
Sailor Moon
%

-- Ed