From: Bill Guindon <agorilla@...>
Date: 2005-03-07T16:49:43+09:00
Subject: Re: YAML to objects - how?

On Mon, 7 Mar 2005 07:46:42 +0900, Joel VanderWerf
<vjoel@path.berkeley.edu> wrote:
> Bill Guindon wrote:
> > Do I need the colons before the field names?  I'm not doing that now.
> 
> Oh, not at all. I just did that because I tend to use symbols rather
> than strings when I am describing attr_accessors and the like. But you
> can use strings for better readability in the yaml file.
> 
> > I'll give that a shot, was wondering if there was a way to auto create
> > objects from the YAML load, but yeah, I could loop through them and do
> > it that way.  I'll see how it goes.
> 
> If you want to autocreate, you can use the syntax for defining the class
> of objects, but the YAML file will look messier. You can see how it will
> look by creating some objects in ruby code, and them calling #to_yaml on
> them. F'rexample:
> 
>    require 'yaml'
> 
>    class C
>      attr_accessor :x
>    end
> 
>    c = C.new
>    c.x = {:foo => ["bar"] }
> 
>    puts c.to_yaml
> 
> The output is
> 
> --- !ruby/object:C
> x:
>    :foo:
>      - bar
> 
> If you YAML.load this, it will create an instance of C.
> 
> Alternately  maybe there is some hook in the YAML parser that lets you
> say "instantiate all hashes with objects of class C", but that seems
> problematic if you use hashes elsewhere in the data.
> 
> Another option is to extend the YAML parser to recognize some custom
> types that have less cumbersome syntax than "!ruby/object:YourClass".
> You can find examples in yaml/types.rb in your ruby lib dir.

I ended up going with your first suggestion (after getting a slightly
firmer grasp of YAML).  The alternatives seem to carry too high a
price for "auto" object creation.

In the long term, I hope that changes, in the short term, looping
through what I have will work fine.

Thx for you input.

-- 
Bill Guindon (aka aGorilla)