fsharp record in discriminated union

Question

I was trying this construct:

type Tree<'a> =
| Leaf 
| Node of { value:'a ; left:Tree<'a> ; right:Tree<'a> }

But f# does not seem to support this (strange). But then how to do this with a separate record type, one then gets stuck in a circular dependency.

Answer 1

Use the keyword and to deal with circular dependencies:

type Rec<'a> = { value:'a ; left:Tree<'a> ; right:Tree<'a> }

and Tree<'a> =
| Leaf 
| Node of Rec<'a>