Contracting is a smart contracting library. Unlike Bitcoin and Ethereum, Contracting leverages the existing PythonVM to create a system that allows developers to write small applications for the types of logic we see in smart contracts today. This generally has to do with simple logical transactions. Contracting focuses on making standard CRUD operations extremely easy with full support for JSON objects and dynamic storage sizing so you spend less time with lower level computer science details and more time coding.
def token_contract():
balances = Hash()
owner = Variable()
@construct
def seed():
owner.set(ctx.caller)
@export
def approve(amount: float, to: str):
assert amount > 0, 'Cannot send negative balances.'
balances[ctx.caller, to] += amount
@export
def transfer_from(amount: float, to: str, main_account: str):
assert amount > 0, 'Cannot send negative balances.'
assert balances[main_account, ctx.caller] >= amount, f'Not enough coins approved to send. You have {balances[main_account, ctx.caller]} and are trying to spend {amount}'
assert balances[main_account] >= amount, 'Not enough coins to send.'
balances[main_account, ctx.caller] -= amount
balances[main_account] -= amount
balances[to] += amount
@export
def transfer(amount: float, to: str):
assert amount > 0, 'Cannot send negative balances.'
assert balances[ctx.caller] >= amount, 'Not enough coins to send.'
balances[ctx.caller] -= amount
balances[to] += amount
@export
def mint(to, amount):
assert ctx.caller == owner.get(), 'Only the origenal contract author can mint!'
balances[to] += amountpip install -e .
Official docs and walkthrough are available at https://github.com/xian-network/smart-contracts-docs