ScalaSTM is hardly experimental. Its reference implementation is based on CCSTM, which has been around for a while now. CCSTM was built by Nathan Bronson, who s

ScalaSTM is hardly experimental. Its reference implementation is based on CCSTM, which has been around for a while now. CCSTM was built by Nathan Bronson, who spent a good chunk of his working life building several transactional memory systems for use in the financial industry. Now he's at Stanford Pervasive Parallelism Lab, where he's built CCSTM and is part of the ScalaSTM expert group. I would have no qualms using ScalaSTM in production today. Whether it is or isn't shipped with the "base library" seems like a red herring. Scala, today, supports the language features necessary to support ScalaSTM. Whether that's packaged and distributed with the language seems superfluous. I never said Clojure won't let you use Actors. I said Clojure won't let you do things it considers to be wrong (e.g., mutable state shared between threads). Like I said, this blog post was a comparison between Actors and STM, and I would have been more interested in seeing a comparison between Clojure's STM and ScalaSTM.