PyTeal subroutine example.py

from pyteal import *


@Subroutine(TealType.uint64)
def factorial_iterative(n):
    """Compute and return n! using loops

    n! = n * (n - 1) * (n - 2) * ... * 1
    """
    i = ScratchVar(TealType.uint64)
    product = ScratchVar(TealType.uint64)

    return Seq(
        product.store(Int(1)),
        For(i.store(Int(1)), i.load() <= n, i.store(i.load() + Int(1))).Do(
            product.store(product.load() * i.load())
        ),
        Return(product.load()),
    )


@Subroutine(TealType.uint64)
def factorial_recursive(n):
    """Compute and return n! using recursion

    n! = n * (n - 1) * (n - 2) * ... * 1
    """
    return Seq(
        # 0! == 1! == 1
        If(n <= Int(1)).Then(Return(Int(1))),
        Return(n * factorial_recursive(n - Int(1))),
    )


def approval_program():

    on_call = Seq(
        App.globalPut(
            Bytes("iterative factorial of 6"), factorial_iterative(Int(6))
        ),  # 720
        App.globalPut(
            Bytes("recursive factorial of 6"), factorial_recursive(Int(6))
        ),  # 720
        Approve(),
    )

    is_creator = Return(Txn.sender() == Global.creator_address())

    program = Cond(
        [Txn.on_completion() == OnComplete.NoOp, on_call],
        [
            Or(
                Txn.on_completion() == OnComplete.OptIn,
                Txn.on_completion() == OnComplete.CloseOut,
            ),
            Reject(),
        ],
        [
            Or(
                Txn.on_completion() == OnComplete.UpdateApplication,
                Txn.on_completion() == OnComplete.DeleteApplication,
            ),
            is_creator,
        ],
    )

    return program


def clear_state_program():
    return Approve()


if __name__ == "__main__":
    with open("demo_approval.teal", "w") as f:
        compiled = compileTeal(approval_program(), mode=Mode.Application, version=4)
        f.write(compiled)

    with open("demo_clear_state.teal", "w") as f:
        compiled = compileTeal(clear_state_program(), mode=Mode.Application, version=4)
        f.write(compiled)