A Brainf*** interpreter written in K. You know, the language that goes like this:
+ increment value at tape pointer - decrement value at tape pointer < decrement tape pointer > increment tape pointer [ jump to the matching right bracket is the value at the tape pointer is 0 ] jump to the matching left bracket is the value at the tape pointer is not 0 . print the value at the tape pointer , read a character from the screen
This interpreter is by no means fast...but it works. Pretty well, too, except that I didn't implement the , character because, as far as I know, reading a single character isn't possible with K2 unless you resort to C extensions. This is written for Kona and K2, NOT kdb+ 3. It will NOT run under kdb+ 3 (if you figure out how without using q, let me know!).
The whole thing is (without comments and blank lines) 378 characters (358 if you remove unnecessary newlines).