take top level /start/ .. /end/ blocks, including nested /start/ .. /end/ blocks

It's unfortunate that the level of nesting needs to be known in advance. The solution would be to replace the use of the binary flip-flop operator with the numeric flip-flop operator. Ie the operator that pre-increments every time its left hand operand is true, and post-decrements every time its right hand operand is true, stays the same otherwise, and returns the result of the calculation.

For some reason, I can't "remember" how the operator is written. Ie what should replace .. to make it numeric, not binary? Any suggestions?