[tempguy9999]

5 mins looking at https://stackoverflow.com/questions/26317325/can-someone-exp... I think I'm getting it. Ops accumulated and composed until they actually have to be evaluated. That's very interesting indeed, thanks, and I'll spend a couple of hours on it.

However, I was using my my example exactly as an example; I was after a symbolic manips app.

The issue of the cost of naively compiled functional languages matters to me as bad performance will kill a good thing.