Ruby 1.9

The speaker, Matz, the creator of Ruby, is introduced at a public talk that will be recorded and shared on YouTube. The audience includes local user groups and external participants. Matz mentions that Google developers are not allowed to use Ruby but expresses interest in their work. He plans to discuss Ruby 1.9, its features, and the language's versioning strategy, which includes a stable version (1.8), a bleeding edge version (1.9), and an innovation bait version (2.0/2.1).

Matz details the incompatibilities introduced in Ruby 1.9, such as changes to block parameters, strings no longer being enumerable, and the handling of Unicode with M17N. He explains the rationale behind these changes, emphasizing the shift towards local variable scope in blocks and the abandonment of strings as enumerable sequences. Matz also highlights new features in Ruby 1.9, including the integration of Unicode support and the introduction of enumerators for more explicit control over iteration.

Matz discusses the enhancements in Ruby 1.9, including the introduction of a new virtual machine called YARV, which stands for Yet Another Ruby VM. YARV is a bytecode interpreter optimized for Ruby, developed by Koichi Sasada. It has significantly improved the performance of Ruby, with core performance improvements ranging from 2 to 50 times faster, depending on the benchmark. However, Matz notes that while the core interpreter is faster, overall program performance improvements are less dramatic due to unchanged libraries and garbage collection.

Matz reflects on the essence of Ruby, which he describes as a combination of the language itself, its community, and various implementations. He expresses pride in the Ruby community, which is known for being friendly and productive. Matz also acknowledges the existence of multiple Ruby implementations, such as MRI, YARV, JRuby, and IronRuby, which have emerged over the years, enhancing the language's versatility and performance across different platforms.

Matz addresses the timing of Ruby's major releases, often coinciding with Christmas, explaining it as a personal choice to have a break after intense work. He also discusses the future of Ruby, including the ongoing work on Ruby 1.9 and the anticipation of Ruby 2.0. Matz hints at the themes of scalability and innovation that will drive the development of Ruby 2.0.

The session concludes with a Q&A, where Matz answers questions about the compatibility of features between Ruby versions, the reasons behind the choice of release dates, and the process of establishing an official Ruby specification through collaboration with the JRuby and Ruby Nous communities. He also touches on the topic of Call/cc, a feature not included in Ruby 1.9 due to its complexity and potential for misuse.

Matz explains Ruby's internal string representation, emphasizing the use of raw byte sequences to avoid encoding conversion issues. He discusses the challenges and efficiency considerations of accessing characters by numeric index in UTF-8 encoded strings, acknowledging potential inefficiencies in certain operations like string reversal but suggesting that Ruby's approach provides a balance that works well in most cases.

During the Q&A, Matz is asked about the implementation of named parameters in Ruby 2.0. He confirms that named parameters will be introduced but clarifies that they will be simpler compared to Python's implementation. Matz describes the syntax for named parameters and how they will be distinguished from hash arguments in the function call syntax.

In the final part of the Q&A, Matz addresses the uncertainty around the exact syntax for Ruby 2.0's features, suggesting that the community will have to wait and see. He wraps up the session with a reminder of the joy and satisfaction that the Ruby language aims to bring to programmers around the world.