Initial ARC-4 support

 Co-authored-by: Daniel McGregor <[email protected]>
 Co-authored-by: Tristan Menzel <[email protected]>

examples/TEALScript/auction/README.md

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+Port of Beaker auction contract to TEALScript. Original source: https://github.com/algorand-devrel/beaker-auction/tree/7e1fe62b852c0d819954a931f10cf39d841cbc02 
+
+

examples/TEALScript/auction/auction.algo.ts

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+import { Contract } from '../../src/lib/index';
+
+// eslint-disable-next-line no-unused-vars
+class Auction extends Contract {
+  previousBidder = GlobalStateKey<Address>();
+
+  auctionEnd = GlobalStateKey<uint64>();
+
+  previousBid = GlobalStateKey<uint64>();
+
+  asaAmt = GlobalStateKey<uint64>();
+
+  asa = GlobalStateKey<Asset>();
+
+  claimableAmount = LocalStateKey<uint64>();
+
+  createApplication(): void {
+    this.auctionEnd.value = 0;
+    this.previousBid.value = 0;
+    this.asaAmt.value = 0;
+    this.asa.value = Asset.zeroIndex;
+
+    // Use zero address rather than an empty string for Account type safety
+    this.previousBidder.value = globals.zeroAddress;
+  }
+
+  optIntoAsset(asset: Asset): void {
+    /// Only allow app creator to opt the app account into a ASA
+    verifyTxn(this.txn, { sender: globals.creatorAddress });
+
+    /// Verify a ASA hasn't already been opted into
+    assert(this.asa.value === Asset.zeroIndex);
+
+    /// Save ASA ID in global state
+    this.asa.value = asset;
+
+    /// Submit opt-in transaction: 0 asset transfer to self
+    sendAssetTransfer({
+      assetReceiver: this.app.address,
+      xferAsset: asset,
+      assetAmount: 0,
+    });
+  }
+
+  startAuction(startingPrice: uint64, length: uint64, axfer: AssetTransferTxn): void {
+    verifyTxn(this.txn, { sender: globals.creatorAddress });
+
+    /// Ensure the auction hasn't already been started
+    assert(this.auctionEnd.value === 0);
+
+    /// Verify axfer
+    verifyTxn(axfer, { assetReceiver: this.app.address });
+
+    /// Set global state
+    this.asaAmt.value = axfer.assetAmount;
+    this.auctionEnd.value = globals.latestTimestamp + length;
+    this.previousBid.value = startingPrice;
+  }
+
+  private pay(receiver: Account, amount: uint64): void {
+    sendPayment({
+      receiver: receiver,
+      amount: amount,
+    });
+  }
+
+  optInToApplication(): void {}
+
+  // eslint-disable-next-line no-unused-vars
+  bid(payment: PayTxn): void {
+    /// Ensure auction hasn't ended
+    assert(globals.latestTimestamp < this.auctionEnd.value);
+
+    /// Verify payment transaction
+    verifyTxn(payment, {
+      sender: this.txn.sender,
+      amount: { greaterThan: this.previousBid.value },
+    });
+
+    /// Set global state
+    this.previousBid.value = payment.amount;
+    this.previousBidder.value = payment.sender;
+
+    /// Update claimable amount
+    this.claimableAmount(this.txn.sender).value = payment.amount;
+  }
+
+  claimBids(): void {
+    const originalAmount = this.claimableAmount(this.txn.sender).value;
+    let amount = originalAmount;
+
+    /// subtract previous bid if sender is previous bidder
+    if (this.txn.sender === this.previousBidder.value) amount = amount - this.previousBid.value;
+
+    this.pay(this.txn.sender, amount);
+    this.claimableAmount(this.txn.sender).value = originalAmount - amount;
+  }
+
+  claim_asset(asset: Asset): void {
+    assert(globals.latestTimestamp > this.auctionEnd.value);
+
+    /// Send ASA to previous bidder
+    sendAssetTransfer({
+      assetReceiver: this.previousBidder.value,
+      xferAsset: asset,
+      assetAmount: this.asaAmt.value,
+      assetCloseTo: this.previousBidder.value,
+    });
+  }
+
+  deleteApplication(): void {
+    sendPayment({
+      receiver: globals.creatorAddress,
+      closeRemainderTo: globals.creatorAddress,
+      amount: 0,
+    });
+  }
+}

examples/TEALScript/auction/contract.py

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+from algopy import (
+    ARC4Contract,
+    AssetTransferTransaction,
+    CreateInnerTransaction,
+    Global,
+    Local,
+    PaymentTransaction,
+    Transaction,
+    TransactionType,
+    UInt64,
+    arc4,
+    subroutine,
+)
+from algopy._reference import Asset
+
+
+class Auction(ARC4Contract):
+    def __init__(self) -> None:
+        self.auction_end = UInt64(0)
+        self.previous_bid = UInt64(0)
+        self.asa_amount = UInt64(0)
+        self.asa = Asset(0)
+        # Use zero address rather than an empty string for Account type safety
+        self.previous_bidder = Global.zero_address()
+        self.claimable_amount = Local(UInt64)
+
+    @arc4.abimethod
+    def opt_into_asset(self, asset: Asset) -> None:
+        # Only allow app creator to opt the app account into a ASA
+        assert Transaction.sender() == Global.creator_address(), "Only creator can opt in to ASA"
+        # Verify a ASA hasn't already been opted into
+        assert self.asa.asset_id == 0, "ASA already opted in"
+        # Save ASA ID in global state
+        self.asa = asset
+
+        # Submit opt-in transaction: 0 asset transfer to self
+        CreateInnerTransaction.begin()
+        CreateInnerTransaction.set_type_enum(TransactionType.AssetTransfer)
+        CreateInnerTransaction.set_fee(UInt64(0))  # cover fee with outer txn
+        CreateInnerTransaction.set_asset_receiver(Global.current_application_address())
+        CreateInnerTransaction.set_xfer_asset(asset.asset_id)
+        CreateInnerTransaction.submit()
+
+    @arc4.abimethod
+    def start_auction(
+        self, starting_price: arc4.UInt64, length: arc4.UInt64, axfer: AssetTransferTransaction
+    ) -> None:
+        assert (
+            Transaction.sender() == Global.creator_address()
+        ), "auction must be started by creator"
+
+        # Ensure the auction hasn't already been started
+        assert self.auction_end == 0, "auction already started"
+
+        # Verify axfer
+        assert (
+            axfer.asset_receiver == Global.current_application_address()
+        ), "axfer must transfer to this app"
+
+        # Set global state
+        self.asa_amount = axfer.asset_amount
+        self.auction_end = Global.latest_timestamp() + length.decode()
+        self.previous_bid = starting_price.decode()
+
+    @arc4.abimethod
+    def opt_in(self) -> None:
+        pass
+
+    @arc4.abimethod
+    def bid(self, pay: PaymentTransaction) -> None:
+        # Ensure auction hasn't ended
+        assert Global.latest_timestamp() < self.auction_end, "auction has ended"
+
+        # Verify payment transaction
+        assert pay.sender == Transaction.sender(), "payment sender must match transaction sender"
+        assert pay.amount > self.previous_bid, "Bid must be higher than previous bid"
+
+        # set global state
+        self.previous_bid = pay.amount
+        self.previous_bidder = pay.sender
+
+        # Update claimable amount
+        self.claimable_amount[Transaction.sender()] = pay.amount
+
+    @arc4.abimethod
+    def claim_bids(self) -> None:
+        original_amount = self.claimable_amount[Transaction.sender()]
+
+        amount = original_amount
+
+        # subtract previous bid if sender is previous bidder
+        if Transaction.sender() == self.previous_bidder:
+            amount -= self.previous_bid
+
+        CreateInnerTransaction.begin()
+        CreateInnerTransaction.set_type_enum(TransactionType.Payment)
+        CreateInnerTransaction.set_fee(UInt64(0))  # cover fee with outer txn
+        CreateInnerTransaction.set_receiver(Transaction.sender())
+        CreateInnerTransaction.set_asset_amount(amount)
+        CreateInnerTransaction.submit()
+
+        self.claimable_amount[Transaction.sender()] = original_amount - amount
+
+    @arc4.abimethod
+    def claim_asset(self, asset: Asset) -> None:
+        assert Global.latest_timestamp() > self.auction_end, "auction has not ended"
+
+        # Send ASA to previous bidder
+        CreateInnerTransaction.begin()
+        CreateInnerTransaction.set_type_enum(TransactionType.AssetTransfer)
+        CreateInnerTransaction.set_fee(UInt64(0))  # cover fee with outer txn
+        CreateInnerTransaction.set_asset_receiver(self.previous_bidder)
+        CreateInnerTransaction.set_xfer_asset(asset.asset_id)
+        CreateInnerTransaction.set_asset_amount(self.asa_amount)
+        CreateInnerTransaction.set_asset_close_to(self.previous_bidder)
+        CreateInnerTransaction.submit()
+
+    @subroutine
+    def delete_application(self) -> None:
+        CreateInnerTransaction.begin()
+        CreateInnerTransaction.set_type_enum(TransactionType.Payment)
+        CreateInnerTransaction.set_fee(UInt64(0))  # cover fee with outer txn
+        CreateInnerTransaction.set_receiver(Global.creator_address())
+        CreateInnerTransaction.set_close_remainder_to(Global.creator_address())
+        CreateInnerTransaction.submit()
+
+    def clear_state_program(self) -> bool:
+        return True