kdb-tick

I agree with you, though in the q world people tend to take it to the extreme, like packing a whole function into a single line rather than a single screen. Here's a ticker plant standard script from KX themselves; I personally find this density makes it harder to read, and when reading it I put it into my text editor and split semicolon-separated statements onto different lines: https://github.com/KxSystems/kdb-tick/blob/master/tick.q E.g. one challenge I've had was generating a magic square on a single line; for odd-size only, I wrote: ms:{{[(m;r;c);i]((.[m;(r;c);:;i],:),$[m[s:(r-1)mod n;d:(c+1) mod n:#:[m]];((r+1)mod n;c);(s;d)])}/[((x;x)#0;0;x div 2);1+!:[x*x]]0}; / but I don't think that's helping anyone

Not a large K program, but a company I used to work for maintains a large, open source q framework https://github.com/AquaQAnalytics/TorQ which is used in many large investment banks and hedgefunds. Funnily enough, the framework is actually a more expansive version of a tick system developed by Kx (the company that makes kdb) https://github.com/KxSystems/kdb-tick The Kx one is incredibly concise. When I first started working with it, it took me a while to figure out what was going on. The larger K/q programs get, the more they tend to look like "normal" code, but you still see a lot of these clever one liners hidden away in there.