Portability: Linux and Windows at least I hope. What about mobile phones, did anyone succeed in getting it to run there? Yes. There is quite some movement about Scala on Android. As for J2ME, I saw something in that respect, but not much. There is some code pertaining to J2ME on the source code repository. … Read more
I’ve done pretty extensive development in Ruby and Groovy (as well as a little Jython using Grinder as a load testing tool). Of the 3, I prefer Groovy the most. I like the closure syntax the best and I think that it has the tightest integration in how it works with other java classes on … Read more
Clojure is always compiled. The Clojure compiler produces Java byte code, which is typically then JIT-compiled to native code by the JVM. The thing that can be confusing is the dynamic and interactive nature of Clojure that means you can invoke the compiler at run-time if you want to. This is all part of the … Read more
You should scope your concurrency appropriately using structured concurrency. Your coroutines can leak if you don’t do this. In your case, scoping them to the processing of a single message seems appropriate. Here’s an example: /* I don’t know Kafka, but let’s pretend this function gets * called when you receive a new message */ … Read more
A partial function is a function that is valid for only a subset of values of those types you might pass in to it. For example: val root: PartialFunction[Double,Double] = { case d if (d >= 0) => math.sqrt(d) } scala> root.isDefinedAt(-1) res0: Boolean = false scala> root(3) res1: Double = 1.7320508075688772 This is useful … Read more
From what I understand, virtualenv enables you to have separate library installation paths, effectively separate “virtual” Python installations. Java doesn’t have the concept of a “system-wide installed” library(*): It always searches the classpath for the libraries to be loaded. Since the classpath can be (and needs to be!) defined for each application, each application can … Read more
tl;dr Summary: Particularly this proposal says that to implement this feature in the language the additional JVM support will be required. When they say “required”, they mean “required in order to be implemented in such a way that it is both performant and interoperable between languages”. So how this feature is implemented without additional support … Read more
If you include the parentheses in the definition you can optionally omit them when you call the method. If you omit them in the definition you can’t use them when you call the method. scala> def foo() {} foo: ()Unit scala> def bar {} bar: Unit scala> foo scala> bar() <console>:12: error: Unit does not … Read more
You may want to investigate Frege. Quoting from that page: “Frege is a non-strict, pure functional programming language in the spirit of Haskell.” “Frege programs are compiled to Java and run in a JVM.” Based on a brief perusal of the language specification, Frege looks to be nearly a Haskell clone. Perhaps the phrase “in … Read more
I would also recommend ASM, but have a look at Jasmin, I used it (or, rather, had to use it) for a university project, and it worked quite well. I wrote a lexer-parser-analyzer-optimizer-generator combination for a programing language using Java and Jasmin, so it was generating JVM Code. I uploaded the code here; the interesting … Read more