DA.Set on JSON-API

Hi Team,

I am seeing in some templates DA.Set is being used in “with” block. May I know what is the right way to incorporate this inside the payload in JSON-API (say in Postman using v1/create)? I have tried an empty [] but it doesn’t work.

Thanks in advance.

kc

See REST JSON Specification - #2 by cocreature for the same question.

As mentioned in there, the :json command in daml repl is very useful for finding the JSON encoding of a given value:

daml> import qualified DA.Set as Set
daml> :json Set.fromList [1,2,3]
{"map":[[1,{}],[2,{}],[3,{}]]}

Hi @cocreature ,

Thanks for your prompt response! It saves my day.

cheers,
kc

We should add this to the doc here:

https://docs.daml.com/json-api/lf-value-specification.html#genmap

To me a small code example would help, so adding one here. If you have a template like:

template Foo
  with
    issuer : Party
    owners : Set.Set Party

Then the JSON will be:

  "payload": {
    "issuer": "<party_name>::<hash>",
    "owners": {
      "map": [
        [
          "<party_name>::<hash>",
          {}
        ],
        [
         "<party_name>::<hash>",
          {}
        ]
      ]
    }
  }