From: "trans.  (T. Onoma)" <transami@...>
Date: 2004-11-15T07:19:55+09:00
Subject: Re: OpenStruct#update ?

On Sunday 14 November 2004 04:27 pm, David A. Black wrote:
| > Why so conservative? So they don't overwrite standard object methods? I
| > wondered why accessors weren't used. I suppose a hash is faster too. Hek,
| > maybe '@' itself should be hash and forget about it ;)
|
| I'm assuming so.  Actually here's what happens if you try:
|
|   irb(main):020:0> o = OpenStruct.new
|   => <OpenStruct>
|   irb(main):021:0> o.class = 1
|   => 1
|   irb(main):022:0> o.class
|   => OpenStruct

Ouch. I think that may be a bit too conservative. It's better that someone can 
shoot themselves in the foot rather than having someone else do it for them. 
I just got stung with:

  require 'yaml'

  q = YAML.load %Q{
  ---
  x: 10  
  y: 20
  ...
  }

  o = OpenStruct.new( q )

  o.instance_eval { x }  #=> 10
  o.instance_eval { y }  #=> nil


| > | But I'm also not sure what you need to do that you can't do.  The
| > | OpenStruct object should let you add values indefinitely.
| >
| > This is what I mean:
| >
| >   o = OpenStruct.new( foo_hash )
| >
| >   # later ...
| >
| >   o.update( bar_hash )
| >
| > The reason is because I am modifying and using the object on the fly.
|
| It's easy to write:
|
|   o = OpenStruct.new({ :a => 1 })
|   def o.update(h); h.each {|k,v| send("#{k}=",v)}; end
|   o.update({ :a => 2})
|   p o.a
|
|   # =>  2

Cool. although I prefer to build it in. I looked at the ostruct.rb code. Very 
simple. All the "safety" logic is in #method_missing, so this is fine:

require 'ostruct'
class OpenStruct
  # Insert/update hash data on the fly.
  def update( hash )
    if hash
      for k,v in hash
        @table[k.to_sym] = v
      end
    end
  end
end

Seems a reasonable addition to standard lib, yes?

Thanks,
T.