Type sections

Example:

type # example demonstrating mutually recursive types
Node = ref object  # an object managed by the garbage collector (ref)
le, ri: Node     # left and right subtrees
sym: ref Sym     # leaves contain a reference to a Sym
Sym = object       # a symbol
  name: string     # the symbol's name
  line: int        # the line the symbol was declared in
  code: Node       # the symbol's abstract syntax tree

A type section begins with the type keyword. It contains multiple type definitions. A type definition binds a type to a name. Type definitions can be recursive or even mutually recursive. Mutually recursive types are only possible within a single type section. Nominal types like objects or enums can only be defined in a type section.