Here are some additional PyTeal example programs:
Atomic Swap allows the transfer of Algos from a buyer to a seller in exchange for a good or service. This is done using a Hashed Time Locked Contract. In this scheme, the buyer funds a TEAL account with the sale price. The buyer also picks a secret value and encodes a secure hash of this value in the TEAL program. The TEAL program will transfer its balance to the seller if the seller is able to provide the secret value that corresponds to the hash in the program. When the seller renders the good or service to the buyer, the buyer discloses the secret from the program. The seller can immediately verify the secret and withdraw the payment.
../examples/signature/atomic_swap.py
Split Payment splits payment between tmpl_rcv1 and tmpl_rcv2 on the ratio of tmpl_ratn / tmpl_ratd.
../examples/signature/split.py
Periodic Payment allows some account to execute periodic withdrawal of funds. This PyTeal program creates an contract account that allows tmpl_rcv to withdraw tmpl_amt every tmpl_period rounds for tmpl_dur after every multiple of tmpl_period.
After tmpl_timeout, all remaining funds in the escrow are available to tmpl_rcv.
../examples/signature/periodic_payment.py
Voting allows accounts to register and vote for arbitrary choices. Here a choice is any byte slice and anyone is allowed to register to vote.
This example has a configurable registration period defined by the global state RegBegin and RegEnd which restrict when accounts can register to vote. There is also a separate configurable voting period defined by the global state VotingBegin and VotingEnd which restrict when voting can take place.
An account must register in order to vote. Accounts cannot vote more than once, and if an account opts out of the application before the voting period has concluded, their vote is discarded. The results are visible in the global state of the application, and the winner is the candidate with the highest number of votes.
../examples/application/vote.py
A reference script that deploys the voting application is below:
../examples/application/vote_deploy.py
Example output for deployment would be:
Registration rounds: 592 to 602
Vote rounds: 603 to 613
Waiting for confirmation...
Transaction KXJHR6J4QSCAHO36L77DPJ53CLZBCCSPSBAOGTGQDRA7WECDXUEA confirmed in round 584.
Created new app-id: 29
Global state: {'RegEnd': 602, 'VoteBegin': 603, 'VoteEnd': 613, 'Creator': '49y8gDrKSnM77cgRyFzYdlkw18SDVNKhhOiS6NVVH8U=', 'RegBegin': 592}
Waiting for round 592
Round 585
Round 586
Round 587
Round 588
Round 589
Round 590
Round 591
Round 592
OptIn from account: FVQEFNOSD25TDBTTTIU2I5KW5DHR6PADYMZESTOCQ2O3ME4OWXEI7OHVRY
Waiting for confirmation...
Transaction YWXOAREFSUYID6QLWQHANTXK3NR2XOVTIQYKMD27F3VXJKP7CMYQ confirmed in round 595.
OptIn to app-id: 29
Waiting for round 603
Round 596
Round 597
Round 598
Round 599
Round 600
Round 601
Round 602
Round 603
Call from account: FVQEFNOSD25TDBTTTIU2I5KW5DHR6PADYMZESTOCQ2O3ME4OWXEI7OHVRY
Waiting for confirmation...
Transaction WNV4DTPEMVGUXNRZHMWNSCUU7AQJOCFTBKJT6NV2KN6THT4QGKNQ confirmed in round 606.
Local state: {'voted': 'choiceA'}
Waiting for round 613
Round 607
Round 608
Round 609
Round 610
Round 611
Round 612
Round 613
Global state: {'RegBegin': 592, 'RegEnd': 602, 'VoteBegin': 603, 'VoteEnd': 613, 'choiceA': 1, 'Creator': '49y8gDrKSnM77cgRyFzYdlkw18SDVNKhhOiS6NVVH8U='}
The winner is: choiceA
Waiting for confirmation...
Transaction 535KBWJ7RQX4ISV763IUUICQWI6VERYBJ7J6X7HPMAMFNKJPSNPQ confirmed in round 616.
Deleted app-id: 29
Waiting for confirmation...
Transaction Z56HDAJYARUC4PWGWQLCBA6TZYQOOLNOXY5XRM3IYUEEUCT5DRMA confirmed in round 618.
Cleared app-id: 29Asset is an implementation of a custom asset type using smart contracts. While Algorand has ASAs, in some blockchains the only way to create a custom asset is through smart contracts.
At creation, the creator specifies the total supply of the asset. Initially this supply is placed in a reserve and the creator is made an admin. Any admin can move funds from the reserve into the balance of any account that has opted into the application using the mint argument. Additionally, any admin can move funds from any account's balance into the reserve using the burn argument.
Accounts are free to transfer funds in their balance to any other account that has opted into the application. When an account opts out of the application, their balance is added to the reserve.
../examples/application/asset.py
Security Token is an extension of the Asset example with more features and restrictions. There are two types of admins, contract admins and transfer admins.
Contract admins can delete the smart contract if the entire supply is in the reserve. They can promote accounts to transfer or contract admins. They can also mint and burn funds.
Transfer admins can impose maximum balance limitations on accounts, temporarily lock accounts, assign accounts to transfer groups, and impose transaction restrictions between transaction groups.
Both contract and transfer admins can pause trading of funds and freeze individual accounts.
Accounts can only transfer funds if trading is not paused, both the sender and receive accounts are not frozen or temporarily locked, transfer group restrictions are not in place between them, and the receiver's account does not have a maximum balance restriction that would be invalidated.
../examples/application/security_token.py