These are some thoughts about the design of a F# library to serialize partially abstract finite tree-shaped data.

Basis

See the considerations in bonsai.

Practical considerations

• tuples
  • struct tuples MS doc: treat as normal tuples
• arrays
  • immutable arrays RFC: treat as array
  • multidimensional arrays MS doc: treat as array of arrays
• sequences: are not data and therefore forbidden
  • although in practice sequences over immutable containers seem to be reiterable, there is no guarantee on the .NET level for this
• discriminated unions MS doc: treat as variants
  • unit equals type void
    • has no value
    • must be special cased and map to the empty tuple
  • option<'a>
    • None has value null
    • this must be special cased
  • list<'a>: is a recursive DU (variant)
    • can not be treated with normal machinery
    • special case and treat as immutable array<'a>
    • treat as immutable Array 'a
    • recursiveness check for DUs
  • enums: should automatically represent as the underlying integer type MS doc
• records
  • anonymous records MS doc: treat as records
  • structures MS doc: treat as records
• std lib containers (optional default representation)
  • Map<'k, 'v> as array<'k * 'v>
  • Set<'a> as array<'a>