> But there's a bigger question: ever since I started writing web apps, I've heard the mantra "keep no state on the server". Arc's continuation or closure thing looks like it's totally breaking the rules. "What about scalability!!", as we say in javaland. So someone's got it all wrong, and why doesn't Hacker News fall over more often?
As far as I know Hacker News is only one server. Presumably it's pretty well tuned, and besides, there may be lots of hackers there, but I'm sure the readership is much less than, say, friendster, which I'm sure has to solve larger scalability problems.
This may also very well be the reason why Yahoo rewrote Viaweb ^^
> the server needs to store 30 separate closures
Closures are cheap ^^. For example in arc2c, a closure has one cell (cell=4 bytes for 32bit, 8 bytes for 64bit) for type, one cell for length, one cell for function, and one additional cell for each captured variable. Often the captured variables are just one or two, so on a 64-bit system you're looking at 40 bytes for each closure.
On the other hand a string might take up just as much space, and would result in not-so-clear code.
