A DAML model showcasing conjunction choices https://medium.com/daml-driven/introducing-conjunction-choices-911cadc98623

PaintHouse.daml

-- Copyright (c) 2019 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
-- SPDX-License-Identifier: Apache-2.0

daml 1.2
module PaintHouse where

template PaintHouse with
    owner : Party
    painter : Party
    cleaner : Party
    price : Decimal
  where
    signatory [owner, painter, cleaner]


template PaintHouseProposal with
    owner : Party
    painter : Party
    cleaner : Party
    price : Decimal
  where
    signatory owner

    controller [painter, cleaner] can
      PaintHouseProposal_Accept : ContractId PaintHouse
        do
          create PaintHouse with owner; painter; cleaner; price


template PainterCleanerRelationship with
    painter : Party
    cleaner : Party
    threshold : Decimal
  where
    signatory [painter, cleaner]

    controller painter can
      nonconsuming AcceptPaintHouse : ContractId PaintHouse with
          cid : ContractId PaintHouseProposal
        do
          paintHouseProposal <- fetch cid
          assert (paintHouseProposal.painter == painter)
          assert (paintHouseProposal.cleaner == cleaner)
          assert (paintHouseProposal.price >= threshold)
          exercise cid PaintHouseProposal_Accept


template PainterCleanerProposal with
    painter : Party
    cleaner : Party
    threshold : Decimal
  where
    signatory painter

    controller cleaner can
      PainterCleanerProposal_Accept : ContractId PainterCleanerRelationship
        do
          create PainterCleanerRelationship with painter; cleaner; threshold


demo = scenario do
  alice <- getParty "Alice"
  bob <- getParty "Bob"
  carl <- getParty "Carl"

  painterCleanerProposal <- submit bob do
    create PainterCleanerProposal with
      painter = bob
      cleaner = carl
      threshold = 500.0
  painterCleanerRelationship <- submit carl do
    exercise painterCleanerProposal PainterCleanerProposal_Accept

  paintAlicesHouseProposal <- submit alice do
    create PaintHouseProposal with
      owner = alice
      painter = bob
      cleaner = carl
      price = 1000.0
  submit bob do
    exercise painterCleanerRelationship AcceptPaintHouse with
      cid = paintAlicesHouseProposal

  donna <- getParty "Donna"
  eric <- getParty "Eric"

  paintDonnasHouseProposal1 <- submit donna do
    create PaintHouseProposal with
      owner = donna
      painter = bob
      cleaner = eric
      price = 1000000.0
  submitMustFail bob do
    exercise painterCleanerRelationship AcceptPaintHouse with
      cid = paintDonnasHouseProposal1
  submitMustFail bob do
    exercise paintDonnasHouseProposal1 PaintHouseProposal_Accept

  paintDonnasHouseProposal2 <- submit donna do
    create PaintHouseProposal with
      owner = donna
      painter = bob
      cleaner = bob
      price = 1500000.0
  submit bob do
    exercise paintDonnasHouseProposal2 PaintHouseProposal_Accept