From: Kent Dahl <kentda@...>
Date: 2002-09-27T21:01:59+09:00
Subject: Re: object attributes list

William Djaja Tjokroaminata wrote:
> class Customer
>         attr_reader :Customerid, :city
>         def initialize
>                 @Customerid = 123
>                 @city = 'abc'
>         end
> end
> 
> c = Customer.new
> 
> hash = {}
> c.instance_variables.each do |var|
>         var = var.slice (1...(var.length))
>         val = eval "c.#{var}"
>         hash[var] = val
> end
> hash.each_key {|key| puts "\"#{key}\" => \"#{hash[key]}\""}

This works wonders as long as 
1) all instance variables are exposed with a reader
2) no method has the name of an instance variable and does anything
different from returning the variable. 

I'd be more inclined to do something like this (mercilessly refactored
from the above):
<CODE>
class Customer
        attr_reader :Customerid, :city
        def initialize
                @Customerid = 123
                @city = 'abc'
	        @secret = 'hush hush'
        end
	def secret
	  "[confidential]"
	end
end

c = Customer.new

class Object
  def instance_variables_to_hash
    result = {}
    self.instance_variables.each do |var|
      result[var] = eval var
    end
    result
  end
end

hash = c.instance_variables_to_hash
hash.each_key {|key| puts "\"#{key}\" => \"#{hash[key]}\""}
</CODE>

Not sure this will work too well when we get truely private instance
variables (i.e. protected from subclasses... Will they also be protected
from superclasses?)

-- 
(\[ Kent Dahl ]/)_    _~_    __[ http://www.stud.ntnu.no/~kentda/ ]___/~
 ))\_student_/((  \__d L b__/  NTNU - graduate engineering - 5. year  )
( \__\_�|�_/__/ ) _)Industrial economics and technological management(
 \____/_�_\____/ (____engineering.discipline_=_Computer::Technology___)