Return multiple dynamic contracts

Questions
1

Hi Team,

Here is my choice


   choice AcceptRequest : (ContractId VendorRequest,ContractId CC_INFO or ContractId LOAN_INFO or ContractId BASIC_INFO or None )
     with 
       name: Optional Text
       pan : Optional Text
       date_of_birth : Optional Date
       address : Optional Text
       income : Optional Decimal
       credit_score : Optional Int
       employment_history : Optional Text
       bankruptcy_history : Optional Text
       debt_to_income_ratio : Optional Decimal
       phone_number : Optional Text
       employment_information : Optional Text
       credit_history : Optional Text
       assets : Optional Text
       liabilities : Optional Text
       collateral : Optional Text
       loan_type : Optional Text
       loan_amount : Optional Decimal
       interest_rate : Optional Decimal
       term : Optional Int
       status : Optional Text
       date_created : Optional Date
       date_updated : Optional Date  
     controller recipient
      do
       assert(recipient /= sender)
       assert(response == "" )
       a<-create this with
         sender = sender
         recipient = recipient
         response = "Request accepted" 

       if requestType == "CC_INFO"
         then do b<-create CC_INFO with name = name,pan = pan,dateOfBirth = date_of_birth,address = address, income = income, creditScore = credit_score,employmentHistory = employment_history,bankruptcyHistory = bankruptcy_history,debtToIncomeRatio = debt_to_income_ratio, owner1=recipient,owner2=sender 
                 pure(a,b)
         else  
           if (requestType == "LOAN_INFO") 
             then
               do b<- create LOAN_INFO with   name = name, pan = pan,date_of_birth = date_of_birth,address = address,phone_number = phone_number,employment_information = employment_information,credit_history = credit_history,assets = assets, liabilities = liabilities, collateral = collateral, loan_type = loan_type, loan_amount = loan_amount, interest_rate = interest_rate, term = term, status = status,date_created = date_created,date_updated = date_updated
                  pure(a,b)
             else  
               if requestType == "BASIC_INFO" 
                 then do b<- create BASIC_INFO with name = name, pan = pan , dob = date_of_birth,address = address, owner1=recipient,owner2=sender
                         pure(a,b)
                  else 
                    do pure(None)

I want to return

VendorRequest and (CC_INFO or LOAN_INFO or BASIC_INFO ) based on the request type

None - if the request type does not match either CC_INFO or LOAN_INFO or BASIC_INFO
please help me to resolve on returning the Contracts

Thanks in advance :slight_smile:

2

You may be better off with three separate choices here.

If you really want to go down this path, here are a few comments.

First off, you can simplify your if chain at the end by using a case instead:

case requestType of
  "CC_INFO" -> do ...
  "LOAN_INFO" -> do ...
  "BASIC_INFO" -> do ...
  _ -> pure None

That would read better than chained if-then-else in my opinion.

Second, if you’re going to use these strings as dispatch mechanisms, you may want to define a data type for them, to prevent typos. Something like:

data InformationRetrieval = CC_INFO | LOAN_INFO | BASIC_INFO | NO_INFO

Depending on your use-case, it’s entirely possible that you won’t need the NO_INFO case, e.g. if you put it there just to make the compiler happy but you never expect a valid request to supply another value than these three.

Lastly, you seem to be confused about your return types here. The four branches of your conditional seem to return four different types. That is not possible in Daml. What you can do for these situations is to create a wrapper type that has all four types as variants, something like:

data AcceptResult
 = wrap_CC_INFO (ContractId CC_INFO)
 | wrap_LOAN_INFO (ContractId LOAN_INFO)
 | wrap_BASIC_INFO (ContractId BASIC_INFO)
 | wrap_NOTHING

then your choice can always return a result of type AcceptResult.