how return false or value?

[ingo]

some of my procs can have no result so I'd like them to return false or a 
value. For now I have
    
    
    proc lintersect(p1, p2, p3, p4: Vec2, segments=false): (bool, Vec2) =
    .
    if parallel
      return (false, vec2(0,0))
    .
    .
    return (true, vec2(x,y))
    
    
    Run
    
    
    proc findCentre(d1, p1, p2,: Vec2): Vec2 =
      let
        p11 = p1+vec2(-d1.x, d1.y)
        p22 = p2+d1
        c = lintersect(p1,p11,p2,p22)
      if c[0]==true:
        result = c[1]
    
    
    Run

echo findCentre results in (0,0), a value, even if c[0] = false. Do I have to 
keep carrying the (bool, vec2) tuple along or is there a way to return None, 
False ...?