Pyteal Extensions

Additional useful operations for Python

Available Operations

• MulDiv64: calculate m1*m2/d with no overflow on multiplication (TEAL 3+)
• Uint64Array: for when you need convenient integer arrays.
• Mul128, FastExp: Optimize operations that take uints and output bytes (big ints)
• Min, Max: calculate minimum/maximum of 2 expressions, without using slots or evaluating arguments more than once (TEAL 4+)
• LazyAnd, LazyOr: lazily evaluate arguments in And/Or operation
• SaturatingAdd, SaturatingSub: saturating addition/subtraction
• AutoLoadScratchVar: more convenient way to use scratch variables. Removes the need to use .load() everytime, adds .increment() method.
• Inner Transactions: simplified making of inner transactions
  • MakeInnerPaymentTxn, MakeInnerAssetTransferTxn and more!
  • MakeInnerGroupTxn to execute inner atomic group transactions
• SerializeIntegers, DeserializeIntegers, DeserializeIntegersToSlots: serialize/deserialize integers to/from bytes
• GlobalState, LocalState, GlobalStateArray, LocalStateArray, GlobalStateArray2D, LocalStateArray2D: easily access global/local state

State manipulation

GlobalState and LocalState allow for manipulating global and local state respectively. They both have the same interface.

from pyteal import App, Bytes, Int, Seq, TealType
from pytealext import LocalState

user_counter = LocalState("UC", TealType.uint64)
program = Seq(
    # increment using pyteal local state
    App.localPut(Int(0), Bytes("UC"), App.localGet(Int(0), Bytes("UC")) + Int(1)),
    # increment using put/get
    user_counter.put(user_counter.get() + Int(1)),
    # increment using add_assign
    user_counter.add_assign(Int(1))
    # decrement
    user_counter.sub_assign(Int(1))
)

Want to simulate arrays in the global state? Use GlobalStateArray and LocalStateArray. Technically, the indexes can be any uint64 value and don't have to be sequential. Each array element takes one slot in the local/global state.

from pyteal import Assert, For, Int, Return, ScratchVar, Seq
from pytealext import LocalStateArray

user_counters = LocalStateArray("Counters")
    i = ScratchVar()
    accumulator = ScratchVar()
    program = Seq(
        user_counters[0].put(Int(10)),
        user_counters[0].add_assign(Int(1)),
        user_counters[0].sub_assign(Int(2)),
        Assert(user_counters[0].get() == Int(9)),
        # set some other indexes
        user_counters[1].put(Int(9)),
        user_counters[2].put(Int(9)),
        # Indexes can also be accessed with Exprs
        accumulator.store(Int(0)),
        For(i.store(Int(0)), i.load() < Int(3), i.store(i.load() + Int(1))).Do(
            accumulator.store(accumulator.load() + user_counters[i.load()].get())
        ),
        Return(accumulator.load() == Int(27)),
    )

Example usage

Example usage for LazyAnd:

from pyteal import Gtxn, TxnType, Bytes, Int
from pytealext import LazyAnd

# Evaluate fields of some transaction but don't panic if an argument down the line would panic
validation = LazyAnd(
    Gtxn[0].type_enum() == TxnType.ApplicationCall,
    Gtxn[0].application_args.length() == Int(1),
    Gtxn[0].application_args[0] == Bytes("AX"),
)

Installation

pip install pytealext

Testing

pytest

Created by Łukasz Ptak and Paweł Rejkowicz