From: Phrogz <gavin@...>
Date: 2006-10-17T12:45:10+09:00
Subject: Re: dynamically assigning instance variables (redux)

Bil Kleb wrote:
>   Is there a way to dynamically assign instance variables?
[...snip...]
> Actually, I'd like the assignment and make them attr_readers too.

class Foo
  def initialize( hash={} )
    hash.each{ |key,value|
      var_name = "@#{key}"
      instance_variable_set( var_name, value )
      singleton_class = class << self; self; end
      singleton_class.class_eval{
        define_method( key ){
          instance_variable_get( var_name )
        }
        define_method( "#{key}=" ){ |new_value|
          instance_variable_set( var_name, new_value )
        }
      }
    }
  end
end

f = Foo.new :name=>'whee', :age=>12
p f, f.age
#=> #<Foo:0x32b900 @age=12, @name="whee">
#=> 12
f.age=32
p f
#=> #<Foo:0x32b900 @age=32, @name="whee">