From: Ryan Pavlik <rpav@...>
Date: 2003-04-26T06:32:16+09:00
Subject: Re: Persistant data

On Sat, 26 Apr 2003 05:43:03 +0900
Matt Lawrence <matt@black-bart.net> wrote:

> Ok, I've been looking at Marshal, PStore, Madelaine and mnemonic.  None of 
> them seem to provide the simple and transparent mechanism that I'm looking 
> for.
> 
> I'd like to be able to do something like:
> 
> 	arr = PersistantArray.use("<filename>")
> 	hash = PersistentHash.use("<filename>")
> 
<snip> 

If you can hang on for a day or so, I'll release Mephle on Monday.
I just added the ability to write non-networked apps a few nights ago,
along with a SQLite storage driver.

What's Mephle?  Well, let's get to the part you want:

    s = String.new_on(:volume, "abc")

What did this do?  's' is now a String object stored in the volume
:volume (which is just a tag, see next), implicitly on $SERVER (more on
that later).

A volume is just a tag for a storage driver.  You can add a
SQLiteStorage, which stores everything in a single file.  (Also
included is MySQLStorage, which stores stuff in a MySQL db; useful for
larger apps.)

There is a "virtual directory" structure, so you can do this, too:

    s = String.new_on("/strings/my_string", :default, "abcd")

Later, you can recover it by doing the following:

    s = retrieve("/strings/my_string", :default)

The nice part is---just like you want---no worry about file formats, and
it's all transparent.  It's even better than PersistantArray, though,
because _any_ given type can be persisted.  (Marshal is used
internally.)

Of course, this is just a small portion of what Mephle provides; you
also get nice network transparency:

    $C = Mephle::Driver::TCPConnection("remotehost.com", 9000)
    $C.open

    s = Get($C, :default, "/strings/my_string")

Now 's' is a remote reference.  It will act and behave exactly like a
String, except any method calls happen on the remote object.  Even
exceptions will be thrown across the network. :-)

There are other nifty things too, like class_ and method_info
(code-accessible documentation), HTML widget library, automatic
interface generation for objects, and others.  (Don't worry, this is
_not_ tied to HTML, but it does have extensive web interface support.)

Interested? ;)

-- 
Ryan Pavlik <rpav@users.sf.net>

"These monkeys of which you speak... are they mentally
 deficient by human or monkey standards?" - 8BT