Create contracts

Questions Features & Bugs
1

How can I create two contracts at the same time?

2

Hi, @Tinglei_Zhang! Welcome to the forums.

I think “How can I create two contracts at the same time?” could also be asked as “How can I create two contracts within the same transaction?” Let us know if you have something else in mind.

Here is an example:

    choice Split : [AssetId]
      controller owner
      do
        asset1 <- create this with name = name <> "1"
        asset2 <- create this with name = name <> "2"
        return [asset1, asset2]

You can test the example yourself using the Asset template created by daml new TwoContracts. If you additionally exercise that choice within the script, you can see the transaction TX 3 that created the two assets:

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image1126×592 64.4 KB

Not that you would generally split a TV! :grinning:

Does that address your question?

FullCode 
module Main where

import Daml.Script

type AssetId = ContractId Asset

template Asset
  with
    issuer : Party
    owner  : Party
    name   : Text
  where
    ensure name /= ""
    signatory issuer
    observer owner

    choice Give : AssetId
      with
        newOwner : Party
      controller owner
      do create this with
           owner = newOwner

    choice Split : [AssetId]
      controller owner
      do
        asset1 <- create this with name = name <> "1"
        asset2 <- create this with name = name <> "2"
        return [asset1, asset2]


setup : Script AssetId
setup = script do
-- user_setup_begin
  alice <- allocatePartyWithHint "Alice" (PartyIdHint "Alice")
  bob <- allocatePartyWithHint "Bob" (PartyIdHint "Bob")
  aliceId <- validateUserId "alice"
  bobId <- validateUserId "bob"
  createUser (User aliceId (Some alice)) [CanActAs alice]
  createUser (User bobId (Some bob)) [CanActAs bob]
-- user_setup_end

  aliceTV <- submit alice do
    createCmd Asset with
      issuer = alice
      owner = alice
      name = "TV"

  bobTV <- submit alice do
    exerciseCmd aliceTV Give with newOwner = bob

  backToAlice <- submit bob do
    exerciseCmd bobTV Give with newOwner = alice
  
  [asset1, asset2] <- submit alice do
    exerciseCmd backToAlice Split

  return asset1
1 Like