From: Sergey Volkov <gm.vlkv@...>
Date: 2006-05-11T23:31:53+09:00
Subject: Re: plz help with binding

----- Original Message ----- 
From: <benjohn@fysh.org>
Sent: Thursday, May 11, 2006 6:08 AM
Subject: Re: plz help with binding


>> here is my solution, if you are interested,
>> now you can get rid of instance variables in your Ruby code :)
>
> :) Doesn't this still suffer from the previous problem though? The
> "variable" is stored per class, rather than per instance?

Do you mean singleton class?
If so, then it's the same as per instance.
But I need even more - variable stored per add_loc call, I thought I made 
it, here is how:

v = ini is executed every time add_loc is called, so every time new binding 
for local variable v is created, which is referenced in accessor methods;
I can move assignment out of module_eval scope, result is the same:
#
module M
    def add_loc name, reader_only=false, ini=nil
        skl = class << self ; self ; end
        v = ini # create new local variable binding
        skl.module_eval{
           define_method name.to_sym, lambda{ v } # reader
           define_method "#{name}=".to_sym, lambda{ |a| v = a } unless 
reader_only
        }
    end
end
#
class CC ; include M ; end
ca = CC.new
ca.add_loc :pocket, true, [] # array, reader only
ca.add_loc :bag
ca.pocket << 10
ca.bag = :book
#
cb = CC.new
cb.add_loc :address_book, true, {} # hash, reader only
cb.add_loc :bag
cb.address_book["me"] = "my address"
cb.bag = :apple
#
p [ca.pocket, ca.bag]
p [cb.address_book, cb.bag]
---------- Capture Output ----------
[[10], :book]
[{"me"=>"my address"}, :apple]
> Terminated with exit code 0.

what am I missing here?