Repository navigation
PPX: Support open variants #40
Description
Sometimes there are type definitions like this:
type status = [> `Foo | `Bar ]
let handle_status (status : status) : string =
match status with
| `Foo -> "It's Foo!"
| `Bar -> "It's Bar!"
| _ -> "Unknown status."This is useful because this code is "future compatible", meaning a server could add new cases without the client crashing, or the other way around.
Would be nice to support it in melange-json PPX.
Activity
[-]Support open variants[/-][+]PPX: Support open variants[/+]anmonteiro commentedon Nov 28, 2024
in
[> `Foo | `Bar ]there's a type variable like there's a type variable in'a StringMap.t. it would be even nicer to provide the function for'aas well to complete the printing :)andreypopp commentedon Nov 28, 2024
I was referring to this .atd's open enum feature https://atd.readthedocs.io/en/latest/atdgen.html#field-open-enum which works either for poly or regular variants.
andreypopp commentedon Nov 28, 2024
Hm... wondering what's the motivation for this restriction.
anmonteiro commentedon Nov 28, 2024
probably a small optimization? if you don't allocate + create all ints + one string for the one with payload, you save a little bit?