Contract Name:
Vyper_contract
Contract Source Code:
File 1 of 1 : Vyper_contract
# @version 0.2.8
from vyper.interfaces import ERC20
implements: ERC20
event Transfer:
sender: indexed(address)
receiver: indexed(address)
value: uint256
event Approval:
owner: indexed(address)
spender: indexed(address)
value: uint256
name: public(String[64])
symbol: public(String[32])
decimals: public(uint256)
balanceOf: public(HashMap[address, uint256])
allowances: HashMap[address, HashMap[address, uint256]]
totalSupply: public(uint256)
COL: constant(address) = 0xC76FB75950536d98FA62ea968E1D6B45ffea2A55
DEAD: constant(address) = 0x000000000000000000000000000000000000dEaD
RATIO: constant(uint256) = 100 # 1 DUCK equals 100 COL
@external
def __init__():
self.name = 'Unit Protocol'
self.symbol = 'DUCK'
self.decimals = 18
@external
def quack():
"""
Migrate and burn COL for DUCK. Quack quack.
"""
cols: uint256 = ERC20(COL).balanceOf(msg.sender)
ducks: uint256 = cols / RATIO
assert ERC20(COL).transferFrom(msg.sender, DEAD, cols) # dev: not approved
self.totalSupply += ducks
self.balanceOf[msg.sender] += ducks
log Transfer(ZERO_ADDRESS, msg.sender, ducks)
@view
@external
def allowance(owner: address, spender: address) -> uint256:
return self.allowances[owner][spender]
@external
def transfer(receiver: address, amount: uint256) -> bool:
assert receiver not in [self, ZERO_ADDRESS]
self.balanceOf[msg.sender] -= amount
self.balanceOf[receiver] += amount
log Transfer(msg.sender, receiver, amount)
return True
@external
def transferFrom(owner: address, receiver: address, amount: uint256) -> bool:
assert receiver not in [self, ZERO_ADDRESS]
self.balanceOf[owner] -= amount
self.balanceOf[receiver] += amount
if owner != msg.sender and self.allowances[owner][msg.sender] != MAX_UINT256:
self.allowances[owner][msg.sender] -= amount
log Approval(owner, msg.sender, self.allowances[owner][msg.sender])
log Transfer(owner, receiver, amount)
return True
@external
def approve(spender: address, amount: uint256) -> bool:
self.allowances[msg.sender][spender] = amount
log Approval(msg.sender, spender, amount)
return True
@external
def burn(amount: uint256):
self.totalSupply -= amount
self.balanceOf[msg.sender] -= amount
log Transfer(msg.sender, ZERO_ADDRESS, amount)