Ruby 2.0 Implementation Work Begins: What is Ruby 2.0 and What’s New?

The version number goes up to 2.0 but the changes are rather small. Smaller than the ones we made in 1.9. Matz

• Cleanup syntax
• Bytecode export
• Symbol GC
• Remove Proc binding
• Macros
• Getting parse tree
• Getting source code
• Cross thread Fiber migration
• Standard Gem
• Review all standard libraries
• Remove obsolete one standard libraries
• Improve Proc#curry
• Non-blocking I/O
• Dtrace
• GC API (replaceable GC) 

http://www.rubyinside.com/ruby-2-0-implementation-work-begins-what-is-ruby-2-0-and-whats-new-5515.html