gistfile1.nim

type
  parbiter = object
   swappedcoll: bool
   a,b: pshape
  pshape = ptr object

#/ Return the colliding shapes involved for this arbiter.
#/ The order of their cpSpace.collision_type values will match
#/ the order set when the collision handler was registered.
proc getShapes*(arb: PArbiter, a, b: var PShape) {.inline.} =
  if arb.swappedColl.bool:
    a = arb.b
    b = arb.a
  else:
    a = arb.a
    b = arb.b

#/ A macro shortcut for defining and retrieving the shapes from an arbiter.
#define CP_ARBITER_GET_SHAPES(arb, a, b) cpShape *a, *b; cpArbiterGetShapes(arb, &a, &b);
template getShapes*(arb: PArbiter, name1, name2: expr): stmt {.immediate.} =
  var name1, name2: PShape
  getShapes(arb, name1, name2)


var
  arb: PArbiter
  a,b: PShape
getshapes(arb,a,b)