Cannot use Int as Datum property type

[tdiesler]

Area

[] Plutus Foundation Related to the GHC plugin, Haskell-to-Plutus compiler, on-chain code

Summary

When I use Int as property type in a Datum like this ...

data PayoutDatum = PayoutDatum {
    pdEpoch :: Int,
    pdActive :: Bool,
    pdPayout :: Integer,
    pdRemaining :: Integer
  } deriving Show

I get ...

src/Astor/Payout.hs:46:1: error:
    • No instance for (PlutusTx.IsData Int)
        arising from a use of ‘PlutusTx.toData’
    • In the expression: PlutusTx.toData arg_a96t
      In the second argument of ‘PlutusTx.Constr’, namely
        ‘[PlutusTx.toData arg_a96t, PlutusTx.toData arg_a96u,
          PlutusTx.toData arg_a96v, PlutusTx.toData arg_a96w]’
      In the expression:
        (PlutusTx.Constr 0)
          [PlutusTx.toData arg_a96t, PlutusTx.toData arg_a96u,
           PlutusTx.toData arg_a96v, PlutusTx.toData arg_a96w]
   |
46 | PlutusTx.unstableMakeIsData ''PayoutDatum
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Could you perhaps clarify the restrictions on data types in Datum properties?

[ghost]

That's because Plutus uses unbounded integers and there is no point in supporting Int with additional conversions. You can just use Integer.

[tdiesler]

merci

[effectfully]

How about providing a dummy IsData Int instance throwing a TypeError telling the user to use Integer instead?

[ghost]

@effectfully sounds great! I've opened a PR.