This started out as a calculator but is becoming more and more like a full blown functional language interpreter.

Check the manual for more information. You can download the jar file and you will be able to run it as a standalone program. I have it for the 'caclulator' button on my keyboard, but then I would.

You are missing out - get Java

If you don't want to read the manual, try these examples to get you started:

isPrime 1234657

asin 4; sin (asin 4)

4 $ in £; 7 henry * 12 yards; 1 millifortnight in minutes

fun fact 0 = 1 | fact n = n * fact (n-1); fact 100; fact 1000

fun factTailRec n = let fun f(0,acc) = acc | f(n,acc) = f(n-1,n*acc) in f(n,1) end; factTailRec 100; factTailRec 1000