Support ability to define top level record types which are respected in enum

[matiwinnetou]

Consider the following code:

type BidDatum {
  bidder: VerificationKeyHash, bid: Lovelace
}

type Datum {
  // there will always be seller identified by their wallet pub key hash
  seller: VerificationKeyHash,
  // seller sets min amount to bid
  min_bid: Lovelace,
  // seller sets deadline after which no more bids are accepted and an action can be closed
  deadline: POSIXTime,
  // the asset that is being auctioned (NFT + ADA lovelace)
  for_sale: Value,
  // initially highest_bid will be None, which means there are no bids yet
  highest_bid: Option<BidDatum>
}

type Redeemer {
  Close
  Bid { bidder: VerificationKeyHash, bid: Lovelace }
}

I am unhappy about this code from Don't Repeat Yourself principle (DRY). I need to define exactly the same type: BidDatum only because I cannot define Bid outside of the scope of Redeemer. This is far from ideal albeit of course it can work like this but ergonomics and DRY suffers.

I want to be able not to have to define embedded Bid something like this:

type Bid {
  bidder: VerificationKeyHash, bid: Lovelace
}

type Datum {
  // there will always be seller identified by their wallet pub key hash
  seller: VerificationKeyHash,
  // seller sets min amount to bid
  min_bid: Lovelace,
  // seller sets deadline after which no more bids are accepted and an action can be closed
  deadline: POSIXTime,
  // the asset that is being auctioned (NFT + ADA lovelace)
  for_sale: Value,
  // initially highest_bid will be None, which means there are no bids yet
  highest_bid: Option<Bid
}

type Redeemer {
  Close
  Bid
}

[rvcas]

I'm not sure which language supports that

I would do this

type Redeemer {
  Close
  PlaceBid(Bid)
 }

you will be pattern matching regardless

when rdmr is {
  Close -> todo
  PlaceBid(bid) -> todo
}

[matiwinnetou]

I need to experiment with this and will provide feedback. Again it is not that current code I have doesn't compile, it is about ergonomics improvements.