There are a handful of commercial success stories with Scala, like the messaging engine behind Twitter, but not a lot.

I can definitely see how an individual or small team could build something fiendishly clever in Scala that's maybe 2,000 lines of code that does the work of 20,000 lines of code in some other language.

On the other hand, I'm not sure that systems 10x that size developed by bigger teams would succeed in Scala, and I fear for what happens when that 2,000 line Scala system falls into the hands of maintenance programmers.

    There are a handful of commercial success 
    stories with Scala

Correction: There are a handful of commercial success stories with Scala made public. There are companies trying to solve hard problems with Scala that are not necessarily interested in language advocacy.

    small team could build something fiendishly clever in
    Scala that's maybe 2,000 lines of code that does the
    work of 20,000 lines of code

I actually provoke you to pick a language, any language other than assembler, and write a piece of software with both languages, of reasonable complexity (no micro-benchmarks shit), as concise as you can.

If the source-code in Scala is at least 3 times smaller, I'll buy you a drink.

I work as a consultant in Bangalore; most of my daytime job involves reviewing projects (for code quality). I see about 8-10 projects a month (Java/.Net).

There are projects which are just bad, let's ignore those. Those which can be classified as maintainable, are well structured and object-oriented, they abstract implementations behind interfaces etc.

But, they are verbose. I could probably accomplish the same thing in about 3x less code using FP/declarative constructs.

Reminds me of Yegge's Kingdom of Nouns; it is a funny read if you haven't read it yet.

COBOL?

He made his statement in the general sense, and I responded in the general sense. I don't know scala and can't speak to it. But I've heard that exact same sentiment applied to ruby (rails, specifically). But ruby has enabled huge increases in productivity for me over php. So I can safely say that the sentiment that if one is doing something fashionable one must not care about shipping, is full of shit.

Yesterday on HN, someone from FourSquare said they have 150k lines of Scala.

http://news.ycombinator.com/item?id=2679041

Is it safe to assume that would be 300k-450k if written in Java?