From: Phlip <phlip2005@...>
Date: 2008-02-10T03:14:56+09:00
Subject: Re: IRHG -- Dumping T-Nodes

Charles Thornton wrote:

> I have been looking a 'rubynode' .
> 
> The problem is I don't have a clear idea of the
> actual structure of the AST.
> 
> I assume that their is a tree structure of Nodes

Yep. For some, the tree is simply a transliteration of the input. 'if x then y 
end' turns into an 'if' node with leaves containing a condition, a 'then' node, 
and an 'else' node. (So does ? : , by the way!)

For others Ruby statements, the tree is deep and sick. For example, all the 
arguments of a function, and some of its local variables, are packed up into a 
node called "scope", where they don't exactly match their location in the source.

Pull down these files and play with them:

   http://phlip.svnrepository.com/svn/yar_wiki/lib/assert_2_0.rb
   http://phlip.svnrepository.com/svn/yar_wiki/lib/ruby_reflector.rb
   http://phlip.svnrepository.com/svn/yar_wiki/test/assert_2_0_test.rb
   http://phlip.svnrepository.com/svn/yar_wiki/test/ruby_reflector_test.rb

They should, roughly, how to disassemble a transformed list of RubyNode objects 
back into a rough form of Ruby source. To see a tree of nodes in action, add pp 
node to any of the functions like def _if, and run all the tests.

-- 
   Phlip