1) In what context would you need this? I haven't really missed them myself so asking where you'd need to use them :)
2) Something like this:
player.distanceTravelled = y
.. create object enemy at (player.x - x, player.y)
.. player.distanceTralled = 0
Depending on how your player moves you'll need to add into distanceTravelled every tick.
2)Thanks, that solves it.
1) I don't really 'need' this but it would be better if I could use it in mathematical expressions, such as finding all the even numbers between certain intervals.