genpyteal 1.0.1

Generate PyTeal with normal Python

genpyteal

Converts Python to PyTeal. Your mileage will vary depending on how much you deviate from the examples. Its quite easy to get an error by doing something not supported. However, it often still outputs useful PyTeal that you can then fix up.

Installation

pip3 install genpyteal or pip install genpyteal

Warning: The scripts have python3 in them because that is what works on my system. It only works with Python 3. There might be some system where it needs to say python instead. If so, maybe just pull the code from the github repo to change it?

Usage

To generate PyTeal:

genpyteal thescript.py

To generate PyTeal and do syntax highlighting (requires pygmentize and boxes to be installed):

genpyteal thescript.py | niceout

To generate PyTeal and then TEAL:

genteal thescript.py

To show the AST (FST) of a Python program (uses RedBaron .help(), and requires ipython installed):

showast thescript.py

Supported constructs

statement list (= Seq), integer const ( = Int(n)), if/else, while, print (= Log), + ( = Concat(str1, str2) ), True/False (= 1/0), and/or/not ... (maybe something I am forgetting).

Details

You can use a subset of Python. For scratch variables, you will need to initialize them at the beginning of a function, such as x = 0 or s = "tom". It uses that to determine the type. Sometimes you may need to specify Bytes or Int still. Integer/string literals get Int/Bytes added automatically. You can use print instead of Log.

Name the main function app to indicate a stateful application contract, or sig for a LogicSig contract.

For transaction fields, you can leave off the parenthesis, e.g. Txn.sender instead of Txn.sender().

It will assume functions return uint64 unless you specify @bytes or there is no return, which will automatically insert @Subroutine(TealType.none)

If you want to print a number in the log, you can use the numtostr function I made:

from lib import util

def app():
  print("Your number is " + util.numtostr(100))

The best explanation is just to show the examples.

Examples

examples/bool.py

def app():
  amt = 15
  return amt > 10 and amt < 20 or amt == 0

examples/callscratch.py

def g(x):
    return 3

def f(n):
    return g(n)

def app():
    x = f(30)
    name = "Bob"
    print(name)
    return 100

examples/checkgroup.py

PAYTO = Addr('6ZHGHH5Z5CTPCF5WCESXMGRSVK7QJETR63M3NY5FJCUYDHO57VTCMJOBGY')
FEE = 10 * 1000000
ZERO = Global.zero_address()

def no_close_to(i):
  Assert( Gtxn[i].close_remainder_to == ZERO )

def no_rekey(i):
  Assert( Gtxn[i].rekey_to == ZERO )

def verify_payment(i):
  Assert( Gtxn[i].receiver == PAYTO and
          Gtxn[i].amount == Int(FEE) and
          Gtxn[i].type_enum == TxnType.Payment )

def app():
  Assert( Global.group_size == 2 )

  no_close_to(1)
  no_rekey(1)

  verify_payment(1)

  App.globalPut('lastPaymentFrom', Gtxn[1].sender)
  Approve()

examples/ifseq.py

def foo(b):
  x = b

def app():
  foo(10)
  if 1 == 1:
    return 1
  else:
    return 0

examples/inner.py

def pay(amount: uint64, receiver: bytes):
    Begin()
    SetFields({
        TxnField.type_enum: TxnType.Payment,
        TxnField.sender: Global.current_application_address,
        TxnField.amount: amount,
        TxnField.receiver: receiver
        })
    Submit()

def app():
    pay(10, Addr('6ZHGHH5Z5CTPCF5WCESXMGRSVK7QJETR63M3NY5FJCUYDHO57VTCMJOBGY'))
    result = 0
    if Txn.first_valid > 1000000:
        result = 1
    return result

examples/strargs.py

def app():
  name = ""
  name = Txn.application_args[0]
  age = Btoi(Txn.application_args[1])
  if age > 65:
    print("User " + name + " is at retirement age.")
    return 1
  else:
    print("User " + name + " is still young.")
    return 0

examples/swap.py

"""Atomic Swap"""

alice = Addr("6ZHGHH5Z5CTPCF5WCESXMGRSVK7QJETR63M3NY5FJCUYDHO57VTCMJOBGY")
bob = Addr("7Z5PWO2C6LFNQFGHWKSK5H47IQP5OJW2M3HA2QPXTY3WTNP5NU2MHBW27M")
secret = Bytes("base32", "2323232323232323")
timeout = 3000
ZERO_ADDR = Global.zero_address()

def sig(
    tmpl_seller=alice,
    tmpl_buyer=bob,
    tmpl_fee=1000,
    tmpl_secret=secret,
    tmpl_hash_fn=Sha256,
    tmpl_timeout=timeout,
):
    fee_cond = Txn.fee < Int(tmpl_fee)
    is_payment = Txn.type_enum == TxnType.Payment
    no_closeto = Txn.close_remainder_to == ZERO_ADDR
    no_rekeyto = Txn.rekey_to == ZERO_ADDR
    safety_cond = is_payment and no_rekeyto and no_closeto

    recv_cond = (Txn.receiver == tmpl_seller) and (tmpl_hash_fn(Arg(0)) == tmpl_secret)
    esc_cond = (Txn.receiver == tmpl_buyer) and (Txn.first_valid > Int(tmpl_timeout))

    return (fee_cond and safety_cond) and (recv_cond or esc_cond)

examples/usenumtostr.py

from lib import util

def app():
  print("The best number is " + util.numtostr(42))
  return True

examples/whilecallif.py

from lib import util

def proc(n):
  return n * 2

def acceptable(n, target):
  if n >= target:
    print("Acceptable. Diff is " + util.numtostr(n - target))
    return True
  else:
    return False

def app():
  total = 1
  i = 0
  while not acceptable(total, Btoi(Txn.application_args[0])):
    total = proc(total)
    i += 1
  return i

examples/whilesum.py

def app():  
  totalFees = 0
  i = 0
  while i < Global.group_size:
    totalFees = totalFees + Gtxn[i].fee
    i = i + 1
  return 1

lib/util.py

@bytes
def numtostr(num):
  out = "             "
  i = 0
  digit = 0
  n = num
  done = False
  while not done:
    digit = n % 10
    out = SetByte(out, 12-i, digit+48)
    n = n / 10		
    if n == 0: done = True
    i = i + 1
  return Extract(out, 12 - i + 1, i)