From: Brian Candler <B.Candler@...>
Date: 2003-03-17T22:54:41+09:00
Subject: Re: ANN: Madeleine 0.1

On Mon, Mar 17, 2003 at 07:00:35AM +0900, Anders Bengtsson wrote:
> This is the first release of Madeleine. Later releases will have
> features like transparent command generation and clustering, but for
> now the focus is a simple and well-designed implementation of the
> basics.

This is beautiful.

Small suggestion: take class 'Marshal' as a parameter. Then you can choose a
different Marshal-type class like 'YAML'. Although right now YAML is slow,
this would give a language-independent database which you could even edit
with 'vi' (great for data recovery). It might end up containing a lot of
spaces, but it should gzip very well.

Note to WHY: please can we have a YAML::dump(object [,IO]) method, for
symmetry with Marshal?

For testing I just replaced 'Marshal' with 'YAML', added the following:

require 'yaml'
module YAML
  def self.dump(obj,stream)
    stream.write(obj.to_yaml)
  end
end

This gives a database which looks like this:

$ cat dictionary-base/000000000000000000001.snapshot 
--- !ruby/object:Dictionary 
data: 
  foo: the opposite of bar
  bar: the opposite of foo

and a logfile like this:

$ cat dictionary-base/000000000000000000001.command_log 
--- !ruby/object:Addition 
key: baz
value: the opposite of foobar

Having such readable files could go a long way towards addressing the
resistance which may arise towards treating your entire database of (say)
a million customer records as a single opaque binary blob...

Cheers,

Brian.

P.S. Another note to WHY: the last line of YAML output doesn't seem to
contain a trailing newline, which is just a slight nuisance.