From: "trans.  (T. Onoma)" <transami@...>
Date: 2004-11-15T22:44:18+09:00
Subject: Re: OpenStruct#update ?

On Monday 15 November 2004 07:38 am, Robert Klemme wrote:
| "Florian Gross" <flgr@ccan.de> schrieb im Newsbeitrag
| news:2vrj8eF2oj365U1@uni-berlin.de...
|
| > trans. (T. Onoma) wrote:
| > > Sure. Okay first, basically what I was doing, given object o and data
|
| in hash
|
| > > h:
| > >
| > >     h.each do |k,v|
| > >       o.instance_variable_set("@#{k}", v)
| > >       o.instance_eval <<-EOS
| > >         def #{k}; @#{k}; end
| > >         def #{k}=(x); @#{k}=x; end
| > >       EOS
| > >     end
| >
| > h.each do |k,v|
| >    class << o; self; end.send(:attr_accessor, k)
| >    o.k = v
| > end
|
| Are you sure, this works?  IMHO this is more efficient:

Actually the example is pulled inside out from the real method I use which is 
a method of class Object (where it does work). So no the above probably 
doesn't work as give --but was just intended to give approx. notion of what 
I'm doing.

| class << o; self; end.send(:attr_accessor, *h.keys)
| h.each do |k,v|
|    o.send("#{k}=", v)
| end
|
| But it would be even better to check for existing methods in order to not
| overwrite existing methods:
|
| cl = class << o; self; end
| im = cl.instance_methods
| h.each do |k,v|
|    cl.send(:attr_reader, k) unless im.include?(k.to_s)
|    cl.send(:attr_writer, k) unless im.include?("#{k}=")
|    o.send("#{k}=", v)
| end

I'm not sure I want that. Hmm... It's a sticky issue depending largely on the 
particular use case. I think it makes sense for general use, so yes --I'll 
add something like that, thanks. Should it raise an error instead? 

But in the context of an OpenStruct, no. OpenStruct focus is on data.

T.