Hello, I'm searching documentation about extending Ruby to create my own 
   language.

Ruby beeing a metalanguage, it's a little confusing for me when I try to 
imagine where I should I start from...

I'm not talking about designing a compiler or a parser but only altering 
Ruby's behaviours (so, I don't want to use 
http://www.zenspider.com/ZSS/Products/CocoR/)

Thanks