[ruby-core:47078] Re: [ruby-trunk - Feature #6840] YAML tag method

On Wed, Aug 08, 2012 at 09:52:15PM +0900, trans (Thomas Sawyer) wrote:
> 
> Issue #6840 has been updated by trans (Thomas Sawyer).
> 
> 
> As I stated before, for my use case, I do *not* want users to use a support library. In fact, it's not just want, its a requirement. This format must be inter-operable. It doesn't mater if the user is programming in Perl, Python, Javascript or any other language. They need to be able to access the information just as readily. I'm not about to write a library for each possible language. The same holds for Ruby.
> 
> The "foo" type is a very specific YAML specification. If the user simply knows the name and version of the spec then they know what to expect. That's the most important thing. Any "Foo" library I write to support "foo" is just a convenience if it suites the purposes of the specifications user. But usually it will not, and should not. 
> 
> But this isn't really about my specific use case. There is a more fundamental issue here. Having to define a global handler upfront makes it impossible to handle the incoming information dynamically. It is one thing to make something difficult, it's another to make it impossible.

You're welcome to access the AST and translate yourself:

    require 'psych'
    
    Psych.parse_stream("---\n- !foo/2 omg\n- zomg") do |ast|
      ast.each do |node|
        if node.tag
          p [:tag, node.tag, node.to_ruby]
        else
          p [node.class, :notag, node.to_ruby]
        end
      end
    end

You can be as dynamic as you want here.

> I realize it sucks to add core methods, but in this case its really a feature that's needed.

Sorry, I'm not convinced.

-- 
Aaron Patterson
http://tenderlovemaking.com/