Also, I'm curious how their database stacks up: what's it better/worse at? It seems like magic for a program so small to do so much so well. I'd like to know what the tradeoffs are. (Either that or move to their universe.)
K is super-great at vector operations; element-wise addition between two lists of equal length, for example; more powerfully, mapping lists to functions.
The DB stuff we were doing were columnar databases, so it was incredibly fast at doing data analysis and correlations. Not so fast at adding single rows, but if you wanted to take a list of transactions and compare things day-over-day, or do sophisticated statistical operations, you simply had to write a line or two, and watch it take multiple million-element lists and give you an answer in milliseconds. I'm still pretty convinced it was voodoo magic.
When I used it, there was a pretty hefty license fee, but there's a trial version which limits the amount of memory it will use, but can still do quite a bit to give you a sense of the speed (as long as you're doing it right). Remember, no stinkin' loops!
I was kind of afraid you would say that. I wish they'd open-source it.
It's such a pity that Peter Seibel didn't include Arthur Whitney in Coders at Work. I suggested him, IIRC, but he didn't get in. As far as I'm concerned he belongs in the top echelon. Here is what Roger Hui, the J guy and no slouch, said (I love this story):
Someone once asked Peggy Lee who she thought was the best jazz singer. Her answer was, You mean besides Ella? Likewise, the answer to the question Who's the best programmer? is Besides Arthur?
Edit: maybe if I'd included that in my suggestion to Seibel it would have helped :)
It sounds like a total disaster, but after about two weeks (which is a long-ass time to learn a language), everything made perfect sense, and I really enjoyed using it for the rest of the time. It's very powerful and fast to execute, and after you get the hang of it, it's fast to write, too.