Performance of (unit enters region)

// C++ >> ABSTRACT Jass
// :)

loop
    // for every alive unit, u
    set x=GetUnitX(u)
    set y=GetUnitY(u)
    // This would be the unit actually moving; through its movement speed.
    call UpdateUnitPosition(u)
    // This would be the region check...
    // It would check if the units old position was outside/inside; then compare to if it is outside/inside now.
    call ForEveryRegionCheckIfEntered(u,x,y)
endloop

// Understandable?

  // This is an idéa for a script. A desperate try to provide my thoughts.
  // I too do realise that the script in its current shape don't do much.

  // This is a function that would be run periodically

function RegionCheckLoop takes nothing returns nothing
  // For each unit in MyOwnUnitGroup do
  // where u is the EnumUnit()

  set i=GetUnitUserData(u)
  set oldX=udg_oldX[i]
  set oldY=udg_oldY[i]
  set x=GetUnitX(u)
  set y=GetUnitY(u)

  // If point(oldX;oldY) is not within the region but point(x,y) is, do "unit entered region" actions...
  // Checks and actions (no, I'm not writing it all out)
  // lots o' fun code...
  // Finally:

  set udg_oldX[i]=x
  set udg_oldY[i]=y

endfunction