Nim boilerplate

[aEverr]

your concepts are wrong, saying that
    
    
    type CircleShape = concept a
      a.r
      buildCircleProps(a)
    
    
    Run

means that for anything to match CircleShape, it must already have a 
buildCircleProps defined for it. if you do not want that, you remove the 
buildnnnn() lines and then it will compile properly without the boilerplate.