From: Hal Fulton <hal9000@...>
Date: 2004-03-30T03:15:08+09:00
Subject: Re: YAML and initializers

why the lucky stiff wrote:
>> 1. Have you given any thought to preserving comments in  yaml files?
>> E.g., I read in an entire file, modify some stuff, and write it out
>> again -- any practical way to keep the comments?
> 
> Okay, yeah.  It's one of those things I'd like to have, but there hasn't 
> been a big demand for it.  Truly: I'm not too excited about coding it 
> in.  But I could really use it as well.

I understand about not looking forward to coding it.

I've been trying to figure out ways to approach it, and I fear it might
not be practical at all in the general case.

I considered a scheme where I did a to_yaml *twice*, storing the yaml in
a string. This seemed fruitless.

I thought of a template kind of thing, where objects would simply have
their yaml stuck into the text. This also hurts my head.

Then I started thinking of the potential difficulties. Suppose you
load 100 objects, and then dump 101. That seems doable; you just stick
the last one on the end.

But what if you try to put a new object in the middle? How do you
associate comments with yaml lines so that they can be kept together
correctly? How does it even 'know' that a particular object goes with
a particular chunk of text?

Here's a thought. What if you attached singleton methods to each object
that had comments, like #pre_yaml and #post_yaml? These would return
the comment block before and after (whatever that means) the yaml code.
There could also be a hash or something that associated data item names
with their trailing comments.

But this is sheer speculation.


Cheers,
Hal