In Ocaml, you cannot have the same label in different types, see the example
below where
point_2d hides point_3d.

How do people normally code around this restriction? One solution is using
objects, but what other solutions are there? Can 'Polymorphic variants'
solve this?

Also, I am a bit curious why it doesn't help to type explicitely, i.e. to
write
let x:point_3d={x=10.;y=20.;z=30.} ???

/mattias


type point_3d = {
    x:float;
    y:float;
    z:float;
  }

type point_2d = {
    x:float;
    y:float;
  }

# {x=10.;y=20.;z=30.};;
Characters 0-19:
The record field label z belongs to the type point_3d
but is here mixed with labels of type point_2d
# {x=10.;y=20.};;
- : point_2d = {x=10.000000; y=20.000000}