Clojure isn't my cup of tea but that's not important. It's an interesting question, how much belongs under the Mahout tent? There's a tradeoff between excluding useful extensions to the project on the one hand, and becoming a spare parts bin of code of varying levels of maturity and support.
I'm inclined to see Mahout built, like any project, in layers. We've done a good job of that, with collections supporting math, supporting core, supporting examples/utils. core remains uneven, but, it's taking shape and it's to be expected at this stage that the project has lots of fragments that naturally come together or else are weeded out. So I have some concern with getting even core into better shape before considering broadening the tent to include other consumers. (We're not talking about integrating Clojure code into core right? Yeah it ends up as Java bytecode, but that's not quite the issue... it's not understandable and usable to the devs that would be using Java-based Mahout.) And so I have moderate preference for not mixing in other languages yet, just like with the talk of a C# port earlier today. I'm sure it's good code and cool and useful, and deserves support and collaboration and liaising; I'm only wondering about whether it ought be a piece of Mahout - what is the benefit, against the subtle but real drawbacks.
