From: Justin Collins <justincollins@...>
Date: 2009-02-18T05:57:19+09:00
Subject: Re: Marshal.dump fails on extended OpenStruct

Justin Collins wrote:
> Justin Collins wrote:
>> synergism wrote:
>>> If I subclass OpenStruct and extend the subclass, I cannot
>>> Marshal.dump it.  This is apparently because ostruct.rb has its own
>>> custom marshal_dump / marshal_load that only cares about what's in
>>> @table:
>>>
>>>   def marshal_dump
>>>     @table
>>>   end
>>>   def marshal_load(x)
>>>     @table = x
>>>     @table.each_key{|key| new_ostruct_member(key)}
>>>   end
>>>
>>> Is there no way to fix this in ostruct.rb to allow my 'bad' example
>>> below to work?
>>>
>>> require 'pp'
>>> require 'ostruct'
>>>
>>> case ARGV.first
>>>     when /bad/i,nil
>>>         class C < OpenStruct
>>>             def initialize
>>>                 super()
>>>                 @var=123
>>>             end
>>>         end
>>>     when /good/i
>>>         class C
>>>             def initialize
>>>                 @struct=OpenStruct.new
>>>                 @var=123
>>>             end
>>>
>>>             def method_missing method,*args,&block
>>>                 @struct.send method,*args,&block
>>>             end
>>>         end
>>> end
>>>
>>> c=C.new
>>> c.a=:a
>>> pp c
>>> puts 'c.a=%s ' %  c.a
>>> puts 'c var=%s' % c.instance_variable_get('@var')
>>> x=Marshal.load(Marshal.dump(c))
>>>
>>> pp x
>>> puts 'x.a=%s ' %  x.a
>>> puts 'x var=%s' % x.instance_variable_get('@var')
>>>
>>>   
>>
>>
> Let me try that again:
>
> require 'ostruct'
> require 'pp'
>
> class C < OpenStruct
>
>  def initialize *args
>    super
>   @var = 123
>  end   def marshal_dump
>    [@table, Hash[self.instance_variables.map { |v| [v, 
> self.instance_variable_get("#{v}")] }]]
>  end   def marshal_load x
>    @table = x[0]
>    @table.each_key{|key| new_ostruct_member(key)}
>    x[1].each do |k,v|
>      self.instance_variable_set("#{k}", v) unless k.to_sym == :table
>    end
>  end
> end
>
> c=C.new
> c.a=:a
> pp c
> puts 'c.a=%s ' %  c.a
> puts 'c var=%s' % c.instance_variable_get('@var')
> x=Marshal.load(Marshal.dump(c))
>
> pp x
> puts 'x.a=%s ' %  x.a
> puts 'x var=%s' % x.instance_variable_get('@var')
>

I give up. I don't know why the formatting is all weird.

-Justin