FoldOverParties.daml

module FoldOverParties where

import DA.Action

template ContractB
  with
    p : Party
    data1 : Text
    data2 : Text
  where
    signatory p

template ContractA
  with
    p : Party
    keyData : Text
    data1 : Text
    data2 : Text
  where
    signatory p
    key (p, keyData) : (Party, Text)
    maintainer key._1


template T
  with
    p : Party
    keyData : Text
  where
    signatory p
    choice CollabResult : ContractId ContractB
      with
        parties : [Party]
      controller p
      do let data1 = ""; data2 = ""
         let process (data1, data2) party = do
               (cid, someData) <- fetchByKey @ContractA (p, keyData)
               pure if someData.p == party
                 then (someData.data1, data2)
                 else (data1, someData.data2)
         (data1, data2) <- foldlA process ("", "") parties
         create ContractB with data1, data2, p