From: Reginald Tan <redge.tan@...>
Date: 2011-04-27T15:08:40+09:00
Subject: Re: including Enumerable in PStore

Christopher Dicely wrote in post #995252:
> On Tue, Apr 26, 2011 at 6:34 PM, Reginald Tan <redge.tan@gmail.com>
> wrote:
>> I want pstore to be able to do same thing. I've included Enumerable but
>> I do have to implement the each method which I dont know how to go
>> about. Any suggestions? Thanks
>
> It looks like, during a transaction, the content of a PStore is
> represent by a Hash in the instance variable @table, so you if you
> want the PStore to act like a Hash, something like this should work:
>
> class PStore
>   def each &blk
>     in_transaction
>     @table.each &blk
>   end
> end
>
> (If you call this without a block, it looks like you get an enumerator
> over the state of the store as of the transaction it was captured in,
> which can be used outside of that transaction, and that could be
> useful for some things.)
>
> Obviously, this is exploiting details of the implementation rather
> than the public interface, so it's at more risk of getting broken in a
> new version of the library than would be an approach that relies only
> on the public interface.

Thanks. I didnt realized before that opening up a class would give you 
access to instance variables as well. I tried to access the table 
variable before using self.table but there was no getter method defined 
for it so I had a bit of trouble.

Good catch on - being able to get enum and use it outside transaction.

Btw, I find having to do everything in transaction quite annoying and 
tedious. Do you see any better way of implementing it instead of always 
passing a block to transaction()?

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