Introduce sim example

Lash/clean and doc

See merge request grassrootseconomics/sarafu-token!9

.gitignore

@@ -0,0 +1,8 @@
+build/
+dist/
+*.egg-info
+__pycache__
+*.pyc
+gmon.out
+solidity/*.json
+solidity/*.bin

python/MANIFEST.in

@@ -1 +1 @@
-include sarafu_token/data/*
+include erc20_demurrage_token/data/*

python/config/eth.ini

@@ -0,0 +1,2 @@
+[eth]
+provider=http://localhost:8545

python/config/session.ini

@@ -0,0 +1,2 @@
+[session]
+chain_spec=

python/config/token.ini

@@ -0,0 +1,8 @@
+[token]
+redistribution_period=10800
+demurrage_level=50
+supply_limit=0
+symbol=RDT
+name=Redistributed Demurraged Token
+decimals=6
+sink_address=

python/erc20_demurrage_token/__init__.py

@@ -0,0 +1,4 @@
+from .token import (
+        DemurrageToken,
+        DemurrageTokenSettings,
+        )

python/erc20_demurrage_token/data/__init__.py

@@ -0,0 +1,3 @@
+import os
+
+data_dir = os.path.realpath(os.path.dirname(__file__))

python/erc20_demurrage_token/runnable/deploy.py

@@ -0,0 +1,174 @@
+"""Deploy sarafu token
+
+.. moduleauthor:: Louis Holbrook <dev@holbrook.no>
+.. pgp:: 0826EDA1702D1E87C6E2875121D2E7BB88C2A746 
+
+"""
+
+# standard imports
+import sys
+import os
+import json
+import argparse
+import logging
+
+# external imports
+import confini
+from crypto_dev_signer.eth.signer import ReferenceSigner as EIP155Signer
+from crypto_dev_signer.keystore.dict import DictKeystore
+from chainlib.chain import ChainSpec
+from chainlib.eth.nonce import (
+        RPCNonceOracle,
+        OverrideNonceOracle,
+        )
+from chainlib.eth.gas import (
+        RPCGasOracle,
+        OverrideGasOracle,
+        )
+from chainlib.eth.connection import EthHTTPConnection
+from chainlib.eth.tx import receipt
+from chainlib.eth.constant import ZERO_ADDRESS
+
+# local imports
+from erc20_demurrage_token import (
+        DemurrageToken,
+        DemurrageTokenSettings,
+        )
+
+logging.basicConfig(level=logging.WARNING)
+logg = logging.getLogger()
+
+script_dir = os.path.dirname(__file__)
+data_dir = os.path.join(script_dir, '..', 'data')
+
+default_config_dir = os.environ.get('CONFINI_DIR', '/usr/local/share/sarafu-token')
+
+argparser = argparse.ArgumentParser()
+argparser.add_argument('-c', '--config', dest='c', type=str, default=default_config_dir, help='configuration directory')
+argparser.add_argument('-p', '--provider', dest='p', default='http://localhost:8545', type=str, help='Web3 provider url (http only)')
+argparser.add_argument('-w', action='store_true', help='Wait for the last transaction to be confirmed')
+argparser.add_argument('-ww', action='store_true', help='Wait for every transaction to be confirmed')
+argparser.add_argument('-i', '--chain-spec', dest='i', type=str, default='evm:ethereum:1', help='Chain specification string')
+argparser.add_argument('-y', '--key-file', dest='y', type=str, help='Ethereum keystore file to use for signing')
+argparser.add_argument('-v', action='store_true', help='Be verbose')
+argparser.add_argument('-vv', action='store_true', help='Be more verbose')
+argparser.add_argument('-d', action='store_true', help='Dump RPC calls to terminal and do not send')
+argparser.add_argument('--name', type=str, help='Token name')
+argparser.add_argument('--decimals', default=6, type=int, help='Token decimals')
+argparser.add_argument('--gas-price', type=int, dest='gas_price', help='Override gas price')
+argparser.add_argument('--nonce', type=int, help='Override transaction nonce')
+argparser.add_argument('--sink-address', dest='sink_address', default=ZERO_ADDRESS, type=str, help='demurrage level,ppm per minute') 
+argparser.add_argument('--supply-limit', dest='supply_limit', type=int, help='token supply limit (0 = no limit)')
+argparser.add_argument('--redistribution-period', type=int, help='redistribution period, minutes (0 = deactivate)') # default 10080 = week
+argparser.add_argument('--env-prefix', default=os.environ.get('CONFINI_ENV_PREFIX'), dest='env_prefix', type=str, help='environment prefix for variables to overwrite configuration')
+argparser.add_argument('--symbol', type=str, help='Token symbol')
+argparser.add_argument('--demurrage-level', dest='demurrage_level', type=int, help='demurrage level, ppm per minute') 
+args = argparser.parse_args()
+
+if args.vv:
+    logg.setLevel(logging.DEBUG)
+elif args.v:
+    logg.setLevel(logging.INFO)
+
+block_last = args.w
+block_all = args.ww
+
+# process config
+config = confini.Config(args.c)
+config.process()
+args_override = {
+            'TOKEN_REDISTRIBUTION_PERIOD': getattr(args, 'redistribution_period'),
+            'TOKEN_DEMURRAGE_LEVEL': getattr(args, 'demurrage_level'),
+            'TOKEN_SUPPLY_LIMIT': getattr(args, 'supply_limit'),
+            'TOKEN_SYMBOL': getattr(args, 'symbol'),
+            'TOKEN_NAME': getattr(args, 'name'),
+            'TOKEN_DECIMALS': getattr(args, 'decimals'),
+            'TOKEN_SINK_ADDRESS': getattr(args, 'sink_address'),
+            'SESSION_CHAIN_SPEC': getattr(args, 'i'),
+            'ETH_PROVIDER': getattr(args, 'p'),
+        }
+if config.get('TOKEN_NAME') == None:
+    logg.info('token name not set, using symbol {} as name'.format(config.get('TOKEN_SYMBOL')))
+    config.add(config.get('TOKEN_SYMBOL'), 'TOKEN_NAME', True)
+config.dict_override(args_override, 'cli args')
+
+if config.get('TOKEN_SUPPLY_LIMIT') == None:
+    config.add(0, 'TOKEN_SUPPLY_LIMIT', True)
+
+if config.get('TOKEN_REDISTRIBUTION_PERIOD') == None:
+    config.add(10800, 'TOKEN_REDISTRIBUTION_PERIOD', True)
+logg.debug('config loaded:\n{}'.format(config))
+
+passphrase_env = 'ETH_PASSPHRASE'
+if args.env_prefix != None:
+    passphrase_env = args.env_prefix + '_' + passphrase_env
+passphrase = os.environ.get(passphrase_env)
+if passphrase == None:
+    logg.warning('no passphrase given')
+    passphrase=''
+
+signer_address = None
+keystore = DictKeystore()
+if args.y != None:
+    logg.debug('loading keystore file {}'.format(args.y))
+    signer_address = keystore.import_keystore_file(args.y, password=passphrase)
+    logg.debug('now have key for signer address {}'.format(signer_address))
+signer = EIP155Signer(keystore)
+
+chain_spec = ChainSpec.from_chain_str(args.i)
+
+rpc = EthHTTPConnection(args.p)
+nonce_oracle = None
+if args.nonce != None:
+    nonce_oracle = OverrideNonceOracle(signer_address, args.nonce)
+else:
+    nonce_oracle = RPCNonceOracle(signer_address, rpc)
+
+gas_oracle = None
+if args.gas_price !=None:
+    gas_oracle = OverrideGasOracle(price=args.gas_price, conn=rpc, code_callback=DemurrageToken.gas)
+else:
+    gas_oracle = RPCGasOracle(rpc, code_callback=DemurrageToken.gas)
+
+dummy = args.d
+
+token_name = args.name
+if token_name == None:
+    token_name = args.symbol
+
+def main():
+    c = DemurrageToken(chain_spec, signer=signer, gas_oracle=gas_oracle, nonce_oracle=nonce_oracle)
+    settings = DemurrageTokenSettings()
+    settings.name = config.get('TOKEN_NAME')
+    settings.symbol = config.get('TOKEN_SYMBOL')
+    settings.decimals = int(config.get('TOKEN_DECIMALS'))
+    settings.demurrage_level = int(config.get('TOKEN_DEMURRAGE_LEVEL'))
+    settings.period_minutes = int(config.get('TOKEN_REDISTRIBUTION_PERIOD'))
+    settings.sink_address = config.get('TOKEN_SINK_ADDRESS')
+
+    (tx_hash_hex, o) = c.constructor(
+            signer_address,
+            settings,
+            redistribute=settings.period_minutes > 0,
+            cap=int(config.get('TOKEN_SUPPLY_LIMIT')),
+            )
+    if dummy:
+        print(tx_hash_hex)
+        print(o)
+    else:
+        rpc.do(o)
+        if block_last:
+            r = rpc.wait(tx_hash_hex)
+            if r['status'] == 0:
+                sys.stderr.write('EVM revert while deploying contract. Wish I had more to tell you')
+                sys.exit(1)
+            # TODO: pass through translator for keys (evm tester uses underscore instead of camelcase)
+            address = r['contractAddress']
+
+            print(address)
+        else:
+            print(tx_hash_hex)
+
+
+if __name__ == '__main__':
+    main()

python/erc20_demurrage_token/sim/__init__.py

@@ -0,0 +1,2 @@
+from .sim import DemurrageTokenSimulation
+from .error import TxLimitException

python/erc20_demurrage_token/sim/error.py

@@ -0,0 +1,2 @@
+class TxLimitException(RuntimeError):
+    pass

python/erc20_demurrage_token/sim/sim.py

@@ -0,0 +1,257 @@
+# standard imports
+import logging
+
+# external imports
+from chainlib.chain import ChainSpec
+from chainlib.eth.unittest.ethtester import create_tester_signer
+from chainlib.eth.unittest.base import TestRPCConnection
+from chainlib.eth.tx import (
+        receipt,
+        Tx,
+        )
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.gas import (
+        OverrideGasOracle,
+        Gas,
+        )
+from chainlib.eth.address import to_checksum_address
+from chainlib.eth.block import (
+        block_latest,
+        block_by_number,
+        block_by_hash,
+        )
+from crypto_dev_signer.keystore.dict import DictKeystore
+from crypto_dev_signer.eth.signer import ReferenceSigner as EIP155Signer
+from hexathon import (
+        strip_0x,
+        add_0x,
+        )
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+from erc20_demurrage_token.sim.error import TxLimitException
+
+logg = logging.getLogger(__name__)
+
+
+class DemurrageTokenSimulation:
+
+    def __init__(self, chain_str, settings, redistribute=True, cap=0, actors=1):
+        self.chain_spec = ChainSpec.from_chain_str(chain_str)
+        self.accounts = []
+        self.keystore = DictKeystore()
+        self.signer = EIP155Signer(self.keystore)
+        self.eth_helper = create_tester_signer(self.keystore)
+        self.eth_backend = self.eth_helper.backend
+        self.gas_oracle = OverrideGasOracle(limit=100000, price=1)
+        self.rpc = TestRPCConnection(None, self.eth_helper, self.signer)
+        for a in self.keystore.list():
+            self.accounts.append(add_0x(to_checksum_address(a)))
+        settings.sink_address = self.accounts[0]
+
+        self.actors = []
+        for i in range(actors):
+            idx = i % 10
+            address = self.keystore.new()
+            self.actors.append(address)
+            self.accounts.append(address)
+
+            nonce_oracle = RPCNonceOracle(self.accounts[idx], conn=self.rpc)
+            c = Gas(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle, gas_oracle=self.gas_oracle)
+            (tx_hash, o) = c.create(self.accounts[idx], address, 100000 * 1000000)
+            self.rpc.do(o)
+            o = receipt(tx_hash)
+            r = self.rpc.do(o)
+            if r['status'] != 1:
+                raise RuntimeError('failed gas transfer to account #{}: {} from {}'.format(i, address, self.accounts[idx]))
+            logg.debug('added actor account #{}: {}'.format(i, address))
+
+        o = block_latest()
+        r = self.rpc.do(o)
+        self.last_block = r
+        self.start_block = self.last_block
+
+        o = block_by_number(r)
+        r = self.rpc.do(o)
+        self.last_timestamp = r['timestamp']
+        self.start_timestamp = self.last_timestamp
+        nonce_oracle = RPCNonceOracle(self.accounts[0], conn=self.rpc)
+
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.constructor(self.accounts[0], settings, redistribute=redistribute, cap=cap)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        if (r['status'] != 1):
+            raise RuntimeError('contract deployment failed')
+        self.address = r['contract_address']
+
+        o = c.decimals(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        self.decimals = c.parse_decimals(r)
+
+        self.period_seconds = settings.period_minutes * 60
+
+        self.last_block += 1
+        self.last_timestamp += 1
+        self.period = 1
+        self.period_txs = []
+        self.period_tx_limit = self.period_seconds - 1
+        self.sink_address = settings.sink_address
+
+        logg.info('intialized at block {} timestamp {} period {} demurrage level {} sink address {} (first address in keystore)'.format(
+                self.last_block,
+                self.last_timestamp,
+                settings.period_minutes,
+                settings.demurrage_level,
+                settings.sink_address,
+                )
+            )
+
+        self.eth_helper.disable_auto_mine_transactions()
+
+        self.caller_contract = DemurrageToken(self.chain_spec)
+        self.caller_address = self.accounts[0]
+
+
+    def __check_limit(self):
+        if self.period_tx_limit == len(self.period_txs):
+            raise TxLimitException('reached period tx limit {}'.format(self.period_tx_limit))
+
+
+    def __check_tx(self, tx_hash):
+        o = receipt(tx_hash)
+        rcpt = self.rpc.do(o)
+        if rcpt['status'] == 0:
+            raise RuntimeError('tx {} (block {} index {}) failed'.format(tx_hash, self.last_block, rcpt['transaction_index']))
+        logg.debug('tx {} block {} index {} verified'.format(tx_hash, self.last_block, rcpt['transaction_index']))
+
+
+    def get_now(self):
+        o = block_latest()
+        r = self.rpc.do(o)
+        o = block_by_number(r, include_tx=False)
+        r = self.rpc.do(o)
+        return r['timestamp']
+
+
+    def get_minutes(self):
+        t = self.get_now()
+        return int((t - self.start_timestamp) / 60)
+
+
+    def get_start(self):
+        return self.start_timestamp
+
+
+    def get_period(self):
+        return self.period
+
+    def get_demurrage_modifier(self):
+        o = self.caller_contract.demurrage_amount(self.address, sender_address=self.caller_address)
+        r = self.rpc.do(o)
+        return float(self.caller_contract.parse_demurrage_amount(r) / (10 ** 38))
+
+
+    def from_units(self, v):
+        return v * (10 ** self.decimals)
+
+
+    def mint(self, recipient, value):
+        self.__check_limit()
+        nonce_oracle = RPCNonceOracle(self.accounts[0], conn=self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle, gas_oracle=self.gas_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], recipient, value)
+        self.rpc.do(o)
+        self.__next_block()
+        self.__check_tx(tx_hash)
+        self.period_txs.append(tx_hash)
+        logg.info('mint {} tokens to {} - {}'.format(value, recipient, tx_hash))
+        return tx_hash
+
+
+    def transfer(self, sender, recipient, value):
+        nonce_oracle = RPCNonceOracle(sender, conn=self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle, gas_oracle=self.gas_oracle)
+        (tx_hash, o) = c.transfer(self.address, sender, recipient, value)
+        self.rpc.do(o)
+        self.__next_block()
+        self.__check_tx(tx_hash)
+        self.period_txs.append(tx_hash)
+        logg.info('transfer {} tokens from {} to {} - {}'.format(value, sender, recipient, tx_hash))
+        return tx_hash
+
+
+    def balance(self, holder, base=False):
+        o = None
+        if base:
+            o = self.caller_contract.base_balance_of(self.address, holder, sender_address=self.caller_address)
+        else:
+            o = self.caller_contract.balance_of(self.address, holder, sender_address=self.caller_address)
+        r = self.rpc.do(o)
+        return self.caller_contract.parse_balance_of(r)
+
+
+    def __next_block(self):
+        hsh = self.eth_helper.mine_block()
+        o = block_by_hash(hsh)
+        r = self.rpc.do(o)
+
+        for tx_hash in r['transactions']:
+            o = receipt(tx_hash)
+            rcpt = self.rpc.do(o)
+            if rcpt['status'] == 0:
+                raise RuntimeError('tx {} (block {} index {}) failed'.format(tx_hash, self.last_block, rcpt['transaction_index']))
+            logg.debug('tx {} (block {} index {}) verified'.format(tx_hash, self.last_block, rcpt['transaction_index']))
+
+        logg.debug('now at block {} timestamp {}'.format(r['number'], r['timestamp']))
+
+
+    def next(self):
+        target_timestamp = self.start_timestamp + (self.period * self.period_seconds)
+        logg.debug('warping to {}, {} from start'.format(target_timestamp, target_timestamp - self.start_timestamp))
+        self.last_timestamp = target_timestamp 
+
+        self.eth_helper.time_travel(self.last_timestamp)
+        self.__next_block()
+
+        o = block_by_number(self.last_block)
+        r = self.rpc.do(o)
+        self.last_block = r['number']
+        block_base = self.last_block
+        
+
+        nonce_oracle = RPCNonceOracle(self.accounts[2], conn=self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle, gas_oracle=self.gas_oracle)
+        (tx_hash, o) = c.change_period(self.address, self.accounts[2])
+        self.rpc.do(o)
+
+        for actor in self.actors:
+            nonce_oracle = RPCNonceOracle(actor, conn=self.rpc)
+            c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle, gas_oracle=self.gas_oracle)
+            (tx_hash, o) = c.apply_redistribution_on_account(self.address, actor, actor)
+            self.rpc.do(o)
+
+        nonce_oracle = RPCNonceOracle(self.sink_address, conn=self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle, gas_oracle=self.gas_oracle)
+        (tx_hash, o) = c.apply_redistribution_on_account(self.address, self.sink_address, self.sink_address)
+        self.rpc.do(o)
+        self.__next_block()
+
+        o = block_latest()
+        self.last_block = self.rpc.do(o)
+
+        o = block_by_number(self.last_block)
+        r = self.rpc.do(o)
+        for tx_hash in r['transactions']:
+            o = receipt(tx_hash)
+            rcpt = self.rpc.do(o)
+            if rcpt['status'] == 0:
+                raise RuntimeError('demurrage step failed on block {}'.format(self.last_block))
+
+        self.last_timestamp = r['timestamp']
+        logg.debug('next concludes at block {} timestamp {}, {} after start'.format(self.last_block, self.last_timestamp, self.last_timestamp - self.start_timestamp))
+        self.period += 1
+        self.period_txs = []
+
+        return (self.last_block, self.last_timestamp)

python/erc20_demurrage_token/token.py

@@ -0,0 +1,378 @@
+# standard imports
+import os
+import logging
+
+# external imports
+from chainlib.eth.tx import (
+        TxFactory,
+        TxFormat,
+        )
+from chainlib.hash import keccak256_string_to_hex
+from chainlib.eth.contract import (
+        ABIContractEncoder,
+        ABIContractType,
+        abi_decode_single,
+        )
+from chainlib.eth.constant import ZERO_ADDRESS
+from chainlib.jsonrpc import jsonrpc_template
+from eth_erc20 import ERC20
+from hexathon import (
+        add_0x,
+        strip_0x,
+        )
+
+# local imports
+from erc20_demurrage_token.data import data_dir
+
+logg = logging.getLogger(__name__)
+
+
+class DemurrageTokenSettings:
+
+    def __init__(self):
+        self.name = None
+        self.symbol = None
+        self.decimals = None
+        self.demurrage_level = None
+        self.period_minutes = None
+        self.sink_address = None
+
+
+class DemurrageToken(ERC20):
+
+    __abi = {}
+    __bytecode = {}
+    valid_modes = [
+                'MultiNocap',
+                'SingleNocap',
+                'MultiCap',
+                'SingleCap',
+                ]
+
+    def constructor(self, sender_address, settings, redistribute=True, cap=0, tx_format=TxFormat.JSONRPC):
+        if int(cap) < 0:
+            raise ValueError('cap must be 0 or positive integer')
+        code = DemurrageToken.bytecode(multi=redistribute, cap=cap>0)
+        enc = ABIContractEncoder()
+        enc.string(settings.name)
+        enc.string(settings.symbol)
+        enc.uint256(settings.decimals)
+        enc.uint256(settings.demurrage_level)
+        enc.uint256(settings.period_minutes)
+        enc.address(settings.sink_address)
+        if cap > 0:
+            enc.uint256(cap)
+        code += enc.get()
+        tx = self.template(sender_address, None, use_nonce=True)
+        tx = self.set_code(tx, code)
+        return self.finalize(tx, tx_format)
+
+
+    @staticmethod
+    def gas(code=None):
+        return 3500000
+
+
+    @staticmethod
+    def __to_contract_name(multi, cap):
+        name = 'DemurrageToken'
+        if multi:
+            name += 'Multi'
+        else:
+            name += 'Single'
+        if cap:
+            name += 'Cap'
+        else:
+            name += 'Nocap'
+        logg.debug('bytecode name {}'.format(name))
+        return name
+
+
+    @staticmethod
+    def abi(multi=True, cap=False):
+        name = DemurrageToken.__to_contract_name(multi, cap)
+        if DemurrageToken.__abi.get(name) == None:
+            f = open(os.path.join(data_dir, name + '.json'), 'r')
+            DemurrageToken.__abi[name] = json.load(f)
+            f.close()
+        return DemurrageToken.__abi[name]
+
+
+    @staticmethod
+    def bytecode(multi=True, cap=False):
+        name = DemurrageToken.__to_contract_name(multi, cap)
+        if DemurrageToken.__bytecode.get(name) == None:
+            f = open(os.path.join(data_dir, name + '.bin'), 'r')
+            DemurrageToken.__bytecode[name] = f.read()
+            f.close()
+        return DemurrageToken.__bytecode[name]
+
+
+    def add_minter(self, contract_address, sender_address, address, tx_format=TxFormat.JSONRPC):
+        enc = ABIContractEncoder()
+        enc.method('addMinter')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.address(address)
+        data = enc.get()
+        tx = self.template(sender_address, contract_address, use_nonce=True)
+        tx = self.set_code(tx, data)
+        tx = self.finalize(tx, tx_format)
+        return tx
+
+
+    def remove_minter(self, contract_address, sender_address, address, tx_format=TxFormat.JSONRPC):
+        enc = ABIContractEncoder()
+        enc.method('removeMinter')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.address(address)
+        data = enc.get()
+        tx = self.template(sender_address, contract_address, use_nonce=True)
+        tx = self.set_code(tx, data)
+        tx = self.finalize(tx, tx_format)
+        return tx
+
+
+    def mint_to(self, contract_address, sender_address, address, value, tx_format=TxFormat.JSONRPC):
+        enc = ABIContractEncoder()
+        enc.method('mintTo')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.typ(ABIContractType.UINT256)
+        enc.address(address)
+        enc.uint256(value)
+        data = enc.get()
+        tx = self.template(sender_address, contract_address, use_nonce=True)
+        tx = self.set_code(tx, data)
+        tx = self.finalize(tx, tx_format)
+        return tx
+
+
+    def to_base_amount(self, contract_address, value, sender_address=ZERO_ADDRESS):
+        o = jsonrpc_template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('toBaseAmount')
+        enc.typ(ABIContractType.UINT256)
+        enc.uint256(value)
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        return o
+
+
+    def remainder(self, contract_address, parts, whole, sender_address=ZERO_ADDRESS):
+        o = jsonrpc_template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('remainder')
+        enc.typ(ABIContractType.UINT256)
+        enc.typ(ABIContractType.UINT256)
+        enc.uint256(parts)
+        enc.uint256(whole)
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        return o
+
+
+    def redistributions(self, contract_address, idx, sender_address=ZERO_ADDRESS):
+        o = jsonrpc_template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('redistributions')
+        enc.typ(ABIContractType.UINT256)
+        enc.uint256(idx)
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        return o
+
+
+    def account_period(self, contract_address, address, sender_address=ZERO_ADDRESS):
+        o = jsonrpc_template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('accountPeriod')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.address(address)
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        return o
+
+
+    def to_redistribution_period(self, contract_address, redistribution, sender_address=ZERO_ADDRESS):
+        o = jsonrpc_template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('toRedistributionPeriod')
+        enc.typ(ABIContractType.BYTES32)
+        enc.bytes32(redistribution)
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        return o
+
+
+    def to_redistribution_participants(self, contract_address, redistribution, sender_address=ZERO_ADDRESS):
+        o = jsonrpc_template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('toRedistributionParticipants')
+        enc.typ(ABIContractType.BYTES32)
+        enc.bytes32(redistribution)
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        return o
+
+
+    def to_redistribution_supply(self, contract_address, redistribution, sender_address=ZERO_ADDRESS):
+        o = jsonrpc_template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('toRedistributionSupply')
+        enc.typ(ABIContractType.BYTES32)
+        enc.bytes32(redistribution)
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        return o
+
+
+    def to_redistribution_demurrage_modifier(self, contract_address, redistribution, sender_address=ZERO_ADDRESS):
+        o = jsonrpc_template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('toRedistributionDemurrageModifier')
+        enc.typ(ABIContractType.BYTES32)
+        enc.bytes32(redistribution)
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        return o
+
+
+    def base_balance_of(self, contract_address, address, sender_address=ZERO_ADDRESS):
+        o = jsonrpc_template()
+        o['method'] = 'eth_call'
+        enc = ABIContractEncoder()
+        enc.method('baseBalanceOf')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.address(address)
+        data = add_0x(enc.get())
+        tx = self.template(sender_address, contract_address)
+        tx = self.set_code(tx, data)
+        o['params'].append(self.normalize(tx))
+        o['params'].append('latest')
+        return o
+
+
+    def apply_demurrage(self, contract_address, sender_address):
+        return self.transact_noarg('applyDemurrage', contract_address, sender_address)
+
+
+    def change_period(self, contract_address, sender_address):
+        return self.transact_noarg('changePeriod', contract_address, sender_address)
+
+
+    def apply_redistribution_on_account(self, contract_address, sender_address, address, tx_format=TxFormat.JSONRPC):
+        enc = ABIContractEncoder()
+        enc.method('applyRedistributionOnAccount')
+        enc.typ(ABIContractType.ADDRESS)
+        enc.address(address)
+        data = enc.get()
+        tx = self.template(sender_address, contract_address, use_nonce=True)
+        tx = self.set_code(tx, data)
+        tx = self.finalize(tx, tx_format)
+        return tx
+       
+
+    def actual_period(self, contract_address, sender_address=ZERO_ADDRESS):
+        return self.call_noarg('actualPeriod', contract_address, sender_address=sender_address)
+
+
+    def period_start(self, contract_address, sender_address=ZERO_ADDRESS):
+        return self.call_noarg('periodStart', contract_address, sender_address=sender_address)
+
+
+    def period_duration(self, contract_address, sender_address=ZERO_ADDRESS):
+        return self.call_noarg('periodDuration', contract_address, sender_address=sender_address)
+
+
+    def demurrage_amount(self, contract_address, sender_address=ZERO_ADDRESS):
+        return self.call_noarg('demurrageAmount', contract_address, sender_address=sender_address)
+
+
+    def supply_cap(self, contract_address, sender_address=ZERO_ADDRESS):
+        return self.call_noarg('supplyCap', contract_address, sender_address=sender_address)
+
+
+    @classmethod
+    def parse_actual_period(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_period_start(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_period_duration(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_demurrage_amount(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_remainder(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_to_base_amount(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+    
+    @classmethod
+    def parse_redistributions(self, v):
+        return abi_decode_single(ABIContractType.BYTES32, v)
+
+
+    @classmethod
+    def parse_account_period(self, v):
+        return abi_decode_single(ABIContractType.ADDRESS, v)
+
+
+    @classmethod
+    def parse_to_redistribution_period(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_to_redistribution_item(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)
+
+
+    @classmethod
+    def parse_supply_cap(self, v):
+        return abi_decode_single(ABIContractType.UINT256, v)

python/examples/sim.py

@@ -0,0 +1,76 @@
+# standard imports
+import logging
+
+# local imports
+from erc20_demurrage_token import DemurrageTokenSettings
+from erc20_demurrage_token.sim import DemurrageTokenSimulation
+
+logging.basicConfig(level=logging.WARNING)
+logg = logging.getLogger()
+
+decay_per_minute = 0.000050105908373373 # equals approx 2% per month
+
+# parameters for simulation object
+settings = DemurrageTokenSettings()
+settings.name = 'Simulated Demurrage Token'
+settings.symbol = 'SIM'
+settings.decimals = 6
+settings.demurrage_level = int(decay_per_minute*(10**40))
+settings.period_minutes = 10800 # 1 week in minutes
+chain = 'evm:foochain:42'
+cap = sim.from_units(10 ** 12) # 1 tn token units, with 6 decimal places
+
+# instantiate simulation
+sim = DemurrageTokenSimulation(chain, settings, redistribute=True, cap=cap, actors=10)
+
+# name the usual suspects
+alice = sim.actors[0]
+bob = sim.actors[1]
+carol = sim.actors[2]
+
+# mint and transfer (every single action advances one block, and one second in time)
+sim.mint(alice, sim.from_units(100)) # 10000000 tokens
+sim.mint(bob, sim.from_units(100))
+sim.transfer(alice, carol, sim.from_units(50))
+
+# check that balances have been updated
+assert sim.balance(alice) == sim.from_units(50)
+assert sim.balance(bob) == sim.from_units(100)
+assert sim.balance(carol) == sim.from_units(50)
+
+# advance to next redistribution period
+sim.next()
+
+# inspect balances
+print('alice balance: demurraged {:>9d} base {:>9d}'.format(sim.balance(alice), sim.balance(alice, base=True)))
+print('bob balance:   demurraged {:>9d} base {:>9d}'.format(sim.balance(bob), sim.balance(bob, base=True)))
+print('carol balance: demurraged {:>9d} base {:>9d}'.format(sim.balance(carol), sim.balance(carol, base=True)))
+
+
+# get times
+minutes = sim.get_minutes()
+start = sim.get_now()
+timestamp = sim.get_start()
+period = sim.get_period()
+print('start {} now {} period {} minutes passed {}'.format(start, timestamp, period, minutes))
+
+
+contract_demurrage = 1 - sim.get_demurrage_modifier()    # demurrage in percent (float)
+frontend_demurrage = ((1 - decay_per_minute) ** minutes / 100)   # corresponding demurrage modifier (float)
+demurrage_delta = contract_demurrage - frontend_demurrage      # difference between demurrage in contract and demurrage calculated in frontend
+
+alice_checksum = 50000000 - (50000000 * frontend_demurrage) + (200000000 * frontend_demurrage) # alice's balance calculated with frontend demurrage
+print("""alice frontend balance {}
+alice contract balance {}
+frontend demurrage {}
+contract demurrage {}
+demurrage delta {}""".format(
+    alice_checksum,
+    sim.balance(alice),
+    frontend_demurrage,
+    contract_demurrage,
+    demurrage_delta),
+)
+
+balance_sum = sim.balance(alice) + sim.balance(bob) + sim.balance(carol)
+print('sum of contract demurraged balances {}'.format(balance_sum))

python/requirements.txt

@@ -1,2 +1,3 @@
-chainlib~=0.0.1a7
-crypto-dev-signer~=0.4.13rc2
+chainlib~=0.0.3rc3
+eth-erc20~=0.0.9a4
+crypto-dev-signer~=0.4.14b3

python/sarafu_token/runnable/legacy/deploy.py

@@ -1,133 +0,0 @@
-"""Deploys Sarafu token
-
-.. moduleauthor:: Louis Holbrook <dev@holbrook.no>
-.. pgp:: 0826EDA1702D1E87C6E2875121D2E7BB88C2A746 
-
-"""
-
-# SPDX-License-Identifier: GPL-3.0-or-later
-
-# standard imports
-import sys
-import os
-import json
-import argparse
-import logging
-import time
-from enum import Enum
-
-# third-party imports
-import web3
-from crypto_dev_signer.eth.signer import ReferenceSigner as EIP155Signer
-from crypto_dev_signer.keystore import DictKeystore
-from crypto_dev_signer.eth.helper import EthTxExecutor
-
-logging.basicConfig(level=logging.WARNING)
-logg = logging.getLogger()
-
-logging.getLogger('web3').setLevel(logging.WARNING)
-logging.getLogger('urllib3').setLevel(logging.WARNING)
-
-script_dir = os.path.dirname(__file__)
-data_dir = os.path.join(script_dir, '..', '..', 'data')
-
-
-argparser = argparse.ArgumentParser()
-argparser.add_argument('-p', '--provider', dest='p', default='http://localhost:8545', type=str, help='Web3 provider url (http only)')
-argparser.add_argument('-w', action='store_true', help='Wait for the last transaction to be confirmed')
-argparser.add_argument('-ww', action='store_true', help='Wait for every transaction to be confirmed')
-argparser.add_argument('-e', action='store_true', help='Treat all transactions as essential')
-argparser.add_argument('-i', '--chain-spec', dest='i', type=str, default='Ethereum:1', help='Chain specification string')
-argparser.add_argument('-y', '--key-file', dest='y', type=str, help='Ethereum keystore file to use for signing')
-argparser.add_argument('--name', dest='n', default='Giftable Token', type=str, help='Token name')
-argparser.add_argument('--symbol', dest='s', default='GFT', type=str, help='Token symbol')
-argparser.add_argument('--decimals', dest='d', default=18, type=int, help='Token decimals')
-argparser.add_argument('--minter', action='append', type=str, help='Minter to add')
-argparser.add_argument('--sink-address', type=str, help='Sink address (if not set, signer address is used)')
-argparser.add_argument('--abi-dir', dest='abi_dir', type=str, default=data_dir, help='Directory containing bytecode and abi (default: {})'.format(data_dir))
-
-argparser.add_argument('-v', action='store_true', help='Be verbose')
-argparser.add_argument('taxlevel_minute', type=int, help='Tax level per minute in ppm')
-argparser.add_argument('period_minutes', type=int, help='Redistribution period, in minutes')
-args = argparser.parse_args()
-
-if args.v:
-    logg.setLevel(logging.DEBUG)
-
-block_last = args.w
-block_all = args.ww
-
-w3 = web3.Web3(web3.Web3.HTTPProvider(args.p))
-
-signer_address = None
-keystore = DictKeystore()
-if args.y != None:
-    logg.debug('loading keystore file {}'.format(args.y))
-    signer_address = keystore.import_keystore_file(args.y)
-    logg.debug('now have key for signer address {}'.format(signer_address))
-signer = EIP155Signer(keystore)
-
-chain_pair = args.i.split(':')
-chain_id = int(chain_pair[1])
-
-helper = EthTxExecutor(
-        w3,
-        signer_address,
-        signer,
-        chain_id,
-        block=args.ww,
-    )
-#g = ERC20TxFactory(signer=signer, gas_oracle=gas_oracle, nonce_oracle=nonce_oracle, chain_id=chain_id)
-
-
-def main():
-
-    f = open(os.path.join(args.abi_dir, 'RedistributedDemurrageToken.json'), 'r')
-    abi = json.load(f)
-    f.close()
-
-    f = open(os.path.join(args.abi_dir, 'RedistributedDemurrageToken.bin'), 'r')
-    bytecode = f.read()
-    f.close()
-
-    sink_address = args.sink_address
-    if sink_address == None:
-        sink_address = signer_address
-
-    c = w3.eth.contract(abi=abi, bytecode=bytecode)
-    (tx_hash, rcpt) = helper.sign_and_send(
-            [
-                c.constructor(args.n, args.s, args.d, args.taxlevel_minute, args.period_minutes, sink_address).buildTransaction
-                ],
-            force_wait=True,
-            )
-    logg.debug('tx hash {} rcpt {}'.format(tx_hash, rcpt))
-
-    address = rcpt.contractAddress
-    logg.debug('token contract mined {} {} {} {}'.format(address, args.n, args.s, args.d, args.taxlevel_minute, args.period_minutes, sink_address))
-    c = w3.eth.contract(abi=abi, address=address)
-
-    balance = c.functions.balanceOf(signer_address).call()
-    logg.info('balance {}: {} {}'.format(signer_address, balance, tx_hash))
-
-    if args.minter != None:
-        for a in args.minter:
-            if a == signer_address:
-                continue
-            (tx_hash, rcpt) = helper.sign_and_send(
-                [
-                    c.functions.addMinter(a).buildTransaction,
-                    ],
-                    )
-            logg.debug('minter add {} {}'.format(a, tx_hash))
-
-    if block_last:
-        helper.wait_for()
-
-    print(address)
-
-    sys.exit(0)
-
-
-if __name__ == '__main__':
-    main()

python/setup.cfg

@@ -1,12 +1,15 @@
 [metadata]
-name = sarafu-token
-version = 0.0.1a2
+name = erc20-demurrage-token
+version = 0.0.1b1
 description = ERC20 token with redistributed continual demurrage
 author = Louis Holbrook
 author_email = dev@holbrook.no
 url = https://gitlab.com/grassrootseconomics/sarafu-token
 keywords =
 	ethereum
+	blockchain
+	cryptocurrency
+	erc20
 classifiers =
 	Programming Language :: Python :: 3
 	Operating System :: OS Independent
@@ -24,18 +27,15 @@ licence_files =
 include_package_data = True
 python_requires = >= 3.6
 packages =
-	sarafu_token
-	sarafu_token.runnable.legacy
-install_requires =
-	chainlib~=0.0.1a7
-	crypto-dev-signer~=0.4.13rc2
-	web3==5.12.2
+	erc20_demurrage_token
+	erc20_demurrage_token.runnable
+	erc20_demurrage_token.data
 
 [options.package_data]
 * =
- 	data/RedistributedDemurrageToken.bin
- 	data/RedistributedDemurrageToken.json
+ 	data/DemurrageToken*.bin
+ 	data/DemurrageToken*.json
 
 [options.entry_points]
 console_scripts =
-	sarafu-token-deploy = sarafu_faucet.runnable.legacy.deploy:main
+	erc20-demurrage-token-deploy = erc20_demurrage_token.runnable.deploy:main

python/setup.py

@@ -1,5 +1,24 @@
 from setuptools import setup
 
+requirements = []
+f = open('requirements.txt', 'r')
+while True:
+    l = f.readline()
+    if l == '':
+        break
+    requirements.append(l.rstrip())
+f.close()
+
+test_requirements = []
+f = open('test_requirements.txt', 'r')
+while True:
+    l = f.readline()
+    if l == '':
+        break
+    test_requirements.append(l.rstrip())
+f.close()
+
+
 setup(
         package_data={
             '': [
@@ -7,4 +26,6 @@ setup(
                 ],
             },
         include_package_data=True,
+        install_requires=requirements,
+        tests_require=test_requirements,
         )

python/test.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+set -e
+
+export PYTHONPATH=.
+
+modes=(MultiNocap MultiCap SingleCap SingleNocap)
+for m in ${modes[@]}; do
+	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_period.py
+	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_basic.py
+done
+
+modes=(MultiCap SingleCap)
+for m in ${modes[@]}; do
+	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_cap.py
+done
+
+modes=(SingleCap SingleNocap)
+for m in ${modes[@]}; do
+	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_single.py
+done
+
+modes=(MultiCap MultiNocap)
+for m in ${modes[@]}; do
+	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_pure.py
+	ERC20_DEMURRAGE_TOKEN_TEST_MODE=$m python tests/test_redistribution.py
+done
+
+set +e

python/test_requirements.txt

@@ -0,0 +1,3 @@
+#web3==5.12.2
+eth_tester==0.5.0b3
+py-evm==0.3.0a20

python/tests/base.py

@@ -0,0 +1,213 @@
+# standard imports
+import logging
+import os
+
+# external imports
+from chainlib.eth.unittest.ethtester import EthTesterCase
+from chainlib.eth.tx import (
+        receipt,
+        )
+from chainlib.eth.block import (
+        block_latest,
+        block_by_number,
+        )
+from chainlib.eth.nonce import RPCNonceOracle
+
+# local imports
+from erc20_demurrage_token import (
+        DemurrageTokenSettings,
+        DemurrageToken,
+        )
+
+
+logg = logging.getLogger()
+
+
+#BLOCKTIME = 5 # seconds
+TAX_LEVEL = int(10000 * 2) # 2%
+# calc "1-(0.98)^(1/518400)" <- 518400 = 30 days of blocks
+# 0.00000003897127107225
+#PERIOD = int(60/BLOCKTIME) * 60 * 24 * 30 # month
+PERIOD = 1
+
+
+
+class TestDemurrage(EthTesterCase):
+
+    def setUp(self):
+        super(TestDemurrage, self).setUp()
+
+        self.tax_level = TAX_LEVEL
+        self.period_seconds = PERIOD * 60
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        self.settings = DemurrageTokenSettings()
+        self.settings.name = 'Foo Token'
+        self.settings.symbol = 'FOO'
+        self.settings.decimals = 6
+        self.settings.demurrage_level = TAX_LEVEL * (10 ** 32)
+        self.settings.period_minutes = PERIOD
+        self.settings.sink_address = self.accounts[9]
+        self.sink_address = self.settings.sink_address
+
+        o = block_latest()
+        self.start_block = self.rpc.do(o)
+        
+        o = block_by_number(self.start_block, include_tx=False)
+        r = self.rpc.do(o)
+
+        try:
+            self.start_time = int(r['timestamp'], 16)
+        except TypeError:
+            self.start_time = int(r['timestamp'])
+
+        self.default_supply = 1000000000000
+        self.default_supply_cap = int(self.default_supply * 10)
+
+
+    def deploy(self, interface, mode):
+        tx_hash = None
+        o = None
+        if mode == 'MultiNocap':
+            (tx_hash, o) = interface.constructor(self.accounts[0], self.settings, redistribute=True, cap=0)
+        elif mode == 'SingleNocap':
+            (tx_hash, o) = interface.constructor(self.accounts[0], self.settings, redistribute=False, cap=0)
+        elif mode == 'MultiCap':
+            (tx_hash, o) = interface.constructor(self.accounts[0], self.settings, redistribute=True, cap=self.default_supply_cap)
+        elif mode == 'SingleCap':
+            (tx_hash, o) = interface.constructor(self.accounts[0], self.settings, redistribute=False, cap=self.default_supply_cap)
+        else:
+            raise ValueError('Invalid mode "{}", valid are {}'.format(self.mode, DemurrageToken.valid_modes))
+
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+        self.start_block = r['block_number']
+        self.address = r['contract_address']
+
+        o = block_by_number(r['block_number'])
+        r = self.rpc.do(o)
+        self.start_time = r['timestamp']
+
+        logg.debug('contract address {} start block {} start time {}'.format(self.address, self.start_block, self.start_time))
+
+
+    def tearDown(self):
+        pass
+
+
+class TestDemurrageDefault(TestDemurrage):
+
+    def setUp(self):
+        super(TestDemurrageDefault, self).setUp()
+   
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        self.mode = os.environ.get('ERC20_DEMURRAGE_TOKEN_TEST_MODE')
+        if self.mode == None:
+            self.mode = 'MultiNocap'
+        logg.debug('executing test setup default mode {}'.format(self.mode))
+
+        self.deploy(c, self.mode)
+
+        logg.info('deployed with mode {}'.format(self.mode))
+
+
+class TestDemurrageSingle(TestDemurrage):
+
+    def setUp(self):
+        super(TestDemurrageSingle, self).setUp()
+   
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        self.mode = os.environ.get('ERC20_DEMURRAGE_TOKEN_TEST_MODE')
+        single_valid_modes = [
+                    'SingleNocap',
+                    'SingleCap',
+                    ]
+        if self.mode != None:
+            if self.mode not in single_valid_modes:
+                raise ValueError('Invalid mode "{}" for "single" contract tests, valid are {}'.format(self.mode, single_valid_modes))
+        else:
+            self.mode = 'SingleNocap'
+        logg.debug('executing test setup demurragesingle mode {}'.format(self.mode))
+
+        self.deploy(c, self.mode)
+
+        logg.info('deployed with mode {}'.format(self.mode))
+
+
+class TestDemurrageCap(TestDemurrage):
+
+    def setUp(self):
+        super(TestDemurrageCap, self).setUp()
+   
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        self.mode = os.environ.get('ERC20_DEMURRAGE_TOKEN_TEST_MODE')
+        cap_valid_modes = [
+                    'MultiCap',
+                    'SingleCap',
+                    ]
+        if self.mode != None:
+            if self.mode not in cap_valid_modes:
+                raise ValueError('Invalid mode "{}" for "cap" contract tests, valid are {}'.format(self.mode, cap_valid_modes))
+        else:
+            self.mode = 'MultiCap'
+        logg.debug('executing test setup demurragecap mode {}'.format(self.mode))
+
+        self.deploy(c, self.mode)
+
+        logg.info('deployed with mode {}'.format(self.mode))
+
+
+
+class TestDemurrageReal(TestDemurrage):
+
+    def setUp(self):
+        super(TestDemurrage, self).setUp()
+
+        self.tax_level = int(0.000050105908373373*(10**40))
+        self.period = 10800
+        self.period_seconds = self.period * 60
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        self.settings = DemurrageTokenSettings()
+        self.settings.name = 'Foo Token'
+        self.settings.symbol = 'FOO'
+        self.settings.decimals = 6
+        self.settings.demurrage_level = self.tax_level
+        self.settings.period_minutes = 10800
+        self.settings.sink_address = self.accounts[9]
+        self.sink_address = self.settings.sink_address
+
+        o = block_latest()
+        self.start_block = self.rpc.do(o)
+        
+        o = block_by_number(self.start_block, include_tx=False)
+        r = self.rpc.do(o)
+
+        try:
+            self.start_time = int(r['timestamp'], 16)
+        except TypeError:
+            self.start_time = int(r['timestamp'])
+
+        self.default_supply = 1000000000000
+        self.default_supply_cap = int(self.default_supply * 10)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        self.mode = os.environ.get('ERC20_DEMURRAGE_TOKEN_TEST_MODE')
+        if self.mode == None:
+            self.mode = 'MultiNocap'
+        logg.debug('executing test setup default mode {}'.format(self.mode))
+
+        self.deploy(c, self.mode)
+
+        logg.info('deployed with mode {}'.format(self.mode))
+

python/tests/sim/tests_sim.py

@@ -0,0 +1,73 @@
+# standard imports
+import unittest
+import logging
+
+# local imports
+from erc20_demurrage_token import DemurrageTokenSettings
+from erc20_demurrage_token.sim import DemurrageTokenSimulation
+
+logging.basicConfig(level=logging.INFO)
+logg = logging.getLogger()
+
+
+class TestSim(unittest.TestCase):
+
+    def setUp(self):
+        self.cap = 0
+        settings = DemurrageTokenSettings()
+        settings.name = 'Simulated Demurrage Token'
+        settings.symbol = 'SIM'
+        settings.decimals = 6
+        settings.demurrage_level = 5010590837337300000000000000000000 # equals approx 2% per month
+        settings.period_minutes = 10800 # 1 week in minutes
+        self.sim = DemurrageTokenSimulation('evm:foochain:42', settings, redistribute=True, cap=self.cap, actors=10)
+
+
+    def test_mint(self):
+        self.sim.mint(self.sim.actors[0], 1024)
+        self.sim.next()
+        balance = self.sim.balance(self.sim.actors[0])
+        self.assertEqual(balance, 1023)
+
+
+    def test_transfer(self):
+        self.sim.mint(self.sim.actors[0], 1024)
+        self.sim.transfer(self.sim.actors[0], self.sim.actors[1], 500)
+        self.sim.next()
+        balance = self.sim.balance(self.sim.actors[0])
+        self.assertEqual(balance, 523)
+
+        balance = self.sim.balance(self.sim.actors[1])
+        self.assertEqual(balance, 499)
+
+
+    def test_more_periods(self):
+        self.sim.mint(self.sim.actors[0], 1024)
+        self.sim.mint(self.sim.actors[1], 1024)
+        self.sim.next()
+
+        self.sim.mint(self.sim.actors[0], 1024)
+        self.sim.next()
+
+        balance = self.sim.balance(self.sim.actors[0])
+        self.assertEqual(balance, 2047)
+
+
+    def test_demurrage(self):
+        self.sim.mint(self.sim.actors[0], self.sim.from_units(100))
+        self.sim.mint(self.sim.actors[1], self.sim.from_units(100))
+        self.sim.transfer(self.sim.actors[0], self.sim.actors[2], self.sim.from_units(10))
+        self.sim.next()
+
+        balance = self.sim.balance(self.sim.actors[0])
+        self.assertEqual(balance, 90005520)
+        
+        balance = self.sim.balance(self.sim.actors[1])
+        self.assertEqual(balance, 99995000)
+
+        balance = self.sim.balance(self.sim.actors[1], base=True)
+        self.assertEqual(balance, 100000000)
+
+
+if __name__ == '__main__':
+    unittest.main()

python/tests/sim/tests_sim_limit.py

@@ -0,0 +1,35 @@
+# standard imports
+import unittest
+import logging
+
+# local imports
+from erc20_demurrage_token import DemurrageTokenSettings
+from erc20_demurrage_token.sim import (
+        DemurrageTokenSimulation,
+        TxLimitException,
+        )
+
+logging.basicConfig(level=logging.INFO)
+logg = logging.getLogger()
+
+class TestLimit(unittest.TestCase):
+
+    def setUp(self):
+        self.cap = 0
+        settings = DemurrageTokenSettings()
+        settings.name = 'Simulated Demurrage Token'
+        settings.symbol = 'SIM'
+        settings.decimals = 6
+        settings.demurrage_level = 1
+        settings.period_minutes = 1
+        self.sim = DemurrageTokenSimulation('evm:foochain:42', settings, redistribute=True, cap=self.cap, actors=1)
+
+
+    def test_limit(self):
+        with self.assertRaises(TxLimitException):
+            for i in range(60):
+                self.sim.mint(self.sim.actors[0], i)
+        
+
+if __name__ == '__main__':
+    unittest.main()

python/tests/test_basic.py

@@ -5,206 +5,236 @@ import json
 import logging
 import datetime
 
-# third-party imports
-import web3
-import eth_tester
-import eth_abi
+# external imports
+from chainlib.eth.constant import ZERO_ADDRESS
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+
+# test imports
+from tests.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()
 
-logging.getLogger('web3').setLevel(logging.WARNING)
-logging.getLogger('eth.vm').setLevel(logging.WARNING)
-
 testdir = os.path.dirname(__file__)
 
-#BLOCKTIME = 5 # seconds
-TAX_LEVEL = int(10000 * 2) # 2%
-# calc "1-(0.98)^(1/518400)" <- 518400 = 30 days of blocks
-# 0.00000003897127107225
-#PERIOD = int(60/BLOCKTIME) * 60 * 24 * 30 # month
-PERIOD = 1
-
-
-class Test(unittest.TestCase):
-
-    contract = None
-
-    def setUp(self):
-        eth_params = eth_tester.backends.pyevm.main.get_default_genesis_params({
-            'gas_limit': 9000000,
-            })
-
-        f = open(os.path.join(testdir, '../../solidity/RedistributedDemurrageToken.bin'), 'r')
-        self.bytecode = f.read()
-        f.close()
-
-        f = open(os.path.join(testdir, '../../solidity/RedistributedDemurrageToken.json'), 'r')
-        self.abi = json.load(f)
-        f.close()
-
-
-        backend = eth_tester.PyEVMBackend(eth_params)
-        self.eth_tester =  eth_tester.EthereumTester(backend)
-        provider = web3.Web3.EthereumTesterProvider(self.eth_tester)
-        self.w3 = web3.Web3(provider)
-        self.sink_address = self.w3.eth.accounts[9]
-
-        c = self.w3.eth.contract(abi=self.abi, bytecode=self.bytecode)
-        tx_hash = c.constructor('Foo Token', 'FOO', 6, TAX_LEVEL * (10 ** 32), PERIOD, self.sink_address).transact({'from': self.w3.eth.accounts[0]})
-
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.contract = self.w3.eth.contract(abi=self.abi, address=r.contractAddress)
-
-        self.start_block = self.w3.eth.blockNumber
-        b = self.w3.eth.getBlock(self.start_block)
-        self.start_time = b['timestamp']
-
-
-    def tearDown(self):
-        pass
 
+class TestBasic(TestDemurrageDefault):
 
     def test_hello(self):
-        self.assertEqual(self.contract.functions.actualPeriod().call(), 1)
-        self.eth_tester.time_travel(self.start_time + 61)
-        self.assertEqual(self.contract.functions.actualPeriod().call(), 2)
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        o = c.actual_period(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        
+        self.backend.time_travel(self.start_time + self.period_seconds + 1)
+        o = c.actual_period(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
 
 
     def test_apply_demurrage(self):
         modifier = 10 * (10 ** 37)
-        #demurrage_modifier = self.contract.functions.demurrageModifier().call()
-        #demurrage_modifier &= (1 << 128) - 1
-        demurrage_amount = self.contract.functions.demurrageAmount().call()
-        #self.assertEqual(modifier, demurrage_modifier)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_amount = c.parse_demurrage_amount(r)
         self.assertEqual(modifier, demurrage_amount)
 
-        self.eth_tester.time_travel(self.start_time + 59)
-        #demurrage_modifier = self.contract.functions.demurrageModifier().call()
-        demurrage_amount = self.contract.functions.demurrageAmount().call()
-        #demurrage_modifier &= (1 << 128) - 1
-        #self.assertEqual(modifier, demurrage_modifier)
+        self.backend.time_travel(self.start_time + self.period_seconds - 1)
+        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_amount = c.parse_demurrage_amount(r)
         self.assertEqual(modifier, demurrage_amount)
 
-        self.eth_tester.time_travel(self.start_time + 61)
-        tx_hash = self.contract.functions.applyDemurrage().transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-
-        #demurrage_modifier = self.contract.functions.demurrageModifier().call()
-        demurrage_amount = self.contract.functions.demurrageAmount().call()
-        #demurrage_modifier &= (1 << 128) - 1
-        #self.assertEqual(int(98 * (10 ** 36)), demurrage_modifier)
-        self.assertEqual(int(98 * (10 ** 36)), demurrage_amount)
+        self.backend.time_travel(self.start_time + self.period_seconds + 1)
+        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        o = c.demurrage_amount(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        demurrage_amount = c.parse_demurrage_amount(r)
+        modifier = int(98 * (10 ** 36))
+        self.assertEqual(modifier, demurrage_amount)
 
 
     def test_mint(self):
-        tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[1], 1024).transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        balance = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
         self.assertEqual(balance, 1024)
 
-        tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[1], 976).transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 976)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        balance = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
         self.assertEqual(balance, 2000)
 
-        self.eth_tester.time_travel(self.start_time + 61)
-        balance = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
+
+        self.backend.time_travel(self.start_time + 61)
+        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
         self.assertEqual(balance, int(2000 * 0.98))
 
 
     def test_minter_control(self):
-        with self.assertRaises(eth_tester.exceptions.TransactionFailed):
-            tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[2], 1024).transact({'from': self.w3.eth.accounts[1]})
-           
-        with self.assertRaises(eth_tester.exceptions.TransactionFailed):
-            tx_hash = self.contract.functions.addMinter(self.w3.eth.accounts[1]).transact({'from': self.w3.eth.accounts[1]})
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
 
-        tx_hash = self.contract.functions.addMinter(self.w3.eth.accounts[1]).transact({'from': self.w3.eth.accounts[0]})
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[1], self.accounts[2], 1024)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+            
+        (tx_hash, o) = c.add_minter(self.address, self.accounts[1], self.accounts[1])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
 
-        with self.assertRaises(eth_tester.exceptions.TransactionFailed):
-            tx_hash = self.contract.functions.addMinter(self.w3.eth.accounts[2]).transact({'from': self.w3.eth.accounts[1]})
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.add_minter(self.address, self.accounts[0], self.accounts[1])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[2], 1024).transact({'from': self.w3.eth.accounts[1]})
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[1], self.accounts[2], 1024)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        with self.assertRaises(eth_tester.exceptions.TransactionFailed):
-            tx_hash = self.contract.functions.addMinter(self.w3.eth.accounts[1]).transact({'from': self.w3.eth.accounts[2]})
+        (tx_hash, o) = c.add_minter(self.address, self.accounts[1], self.accounts[2])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
 
-        tx_hash = self.contract.functions.removeMinter(self.w3.eth.accounts[1]).transact({'from': self.w3.eth.accounts[1]})
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
-
-        with self.assertRaises(eth_tester.exceptions.TransactionFailed):
-            tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[2], 1024).transact({'from': self.w3.eth.accounts[1]})
+        (tx_hash, o) = c.remove_minter(self.address, self.accounts[1], self.accounts[1])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[1], self.accounts[2], 1024)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+            
 
     def test_base_amount(self):
-        tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[1], 1000).transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
 
-        self.eth_tester.time_travel(self.start_time + 61)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
+        self.rpc.do(o)
 
-        self.contract.functions.applyDemurrage().transact()
-        #demurrage_modifier = self.contract.functions.demurrageModifier().call()
-        #demurrage_amount = self.contract.functions.toDemurrageAmount(demurrage_modifier).call()
-        demurrage_amount = self.contract.functions.demurrageAmount().call()
-
-        a = self.contract.functions.toBaseAmount(1000).call();
-        self.assertEqual(a, 1020)
+        self.backend.time_travel(self.start_time + 61)
+        (tx_hash, o) = c.apply_demurrage(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        o = c.to_base_amount(self.address, 1000, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        amount = c.parse_to_base_amount(r)
+        self.assertEqual(amount, 1020)
 
 
     def test_transfer(self):
-        tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[1], 1024).transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
 
-        tx_hash = self.contract.functions.transfer(self.w3.eth.accounts[2], 500).transact({'from': self.w3.eth.accounts[1]})
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
-        logg.debug('tx {}'.format(r))
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
+        self.rpc.do(o)
 
-        balance_alice = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
-        self.assertEqual(balance_alice, 524)
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[1], self.accounts[2], 500)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        balance_bob = self.contract.functions.balanceOf(self.w3.eth.accounts[2]).call()
-        self.assertEqual(balance_bob, 500)
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 524)
 
-        tx_hash = self.contract.functions.transfer(self.w3.eth.accounts[2], 500).transact({'from': self.w3.eth.accounts[1]})
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
-        logg.debug('tx {}'.format(r))
+        o = c.balance_of(self.address, self.accounts[2], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 500)
 
+        nonce_oracle = RPCNonceOracle(self.accounts[2], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[2], self.accounts[1], 500)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+       
 
     def test_transfer_from(self):
-        tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[1], 1024).transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
+        self.rpc.do(o)
 
-        tx_hash = self.contract.functions.approve(self.w3.eth.accounts[2], 500).transact({'from': self.w3.eth.accounts[1]})
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
-        logg.debug('tx {}'.format(r))
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.approve(self.address, self.accounts[1], self.accounts[2], 500)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+        
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 1024)
 
-        balance_alice = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
-        self.assertEqual(balance_alice, 1024)
+        nonce_oracle = RPCNonceOracle(self.accounts[2], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer_from(self.address, self.accounts[2], self.accounts[1], self.accounts[3], 500)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+ 
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 524)
 
-        tx_hash = self.contract.functions.transferFrom(self.w3.eth.accounts[1], self.w3.eth.accounts[3], 500).transact({'from': self.w3.eth.accounts[2]})
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
-        logg.debug('tx {}'.format(r))
-
-        balance_alice = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
-        self.assertEqual(balance_alice, 524)
-
-        balance_alice = self.contract.functions.balanceOf(self.w3.eth.accounts[3]).call()
-        self.assertEqual(balance_alice, 500)
+        o = c.balance_of(self.address, self.accounts[3], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, 500)
 
 
 if __name__ == '__main__':

python/tests/test_cap.py

@@ -0,0 +1,67 @@
+import os
+import unittest
+import json
+import logging
+
+# external imports
+from chainlib.eth.constant import ZERO_ADDRESS
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+from chainlib.eth.block import block_latest
+from chainlib.eth.address import to_checksum_address
+from hexathon import (
+        strip_0x,
+        add_0x,
+        )
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+
+# test imports
+from tests.base import TestDemurrageCap
+
+logging.basicConfig(level=logging.DEBUG)
+logg = logging.getLogger()
+
+testdir = os.path.dirname(__file__)
+
+
+class TestCap(TestDemurrageCap):
+
+    def test_cap_set(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        o = c.supply_cap(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        cap = c.parse_supply_cap(r)
+        self.assertEqual(cap, self.default_supply_cap)
+
+
+    def test_cap(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], self.default_supply_cap)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[2], 1)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+
+
+    def test_cap_first(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], self.default_supply_cap + 1)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 0)
+
+
+if __name__ == '__main__':
+    unittest.main()

python/tests/test_period.py

@@ -4,76 +4,64 @@ import unittest
 import json
 import logging
 
-# third-party imports
-import web3
-import eth_tester
-import eth_abi
+# external imports
+from chainlib.eth.constant import ZERO_ADDRESS
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+
+# test imports
+from tests.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()
 
-logging.getLogger('web3').setLevel(logging.WARNING)
-logging.getLogger('eth.vm').setLevel(logging.WARNING)
-
 testdir = os.path.dirname(__file__)
 
-#BLOCKTIME = 5 # seconds
-TAX_LEVEL = 10000 * 2 # 2%
-#PERIOD = int(60/BLOCKTIME) * 60 * 24 * 30 # month
-PERIOD = 1
-
-
-class Test(unittest.TestCase):
-
-    contract = None
-
-    def setUp(self):
-        eth_params = eth_tester.backends.pyevm.main.get_default_genesis_params({
-            'gas_limit': 9000000,
-            })
-
-        f = open(os.path.join(testdir, '../../solidity/RedistributedDemurrageToken.bin'), 'r')
-        self.bytecode = f.read()
-        f.close()
-
-        f = open(os.path.join(testdir, '../../solidity/RedistributedDemurrageToken.json'), 'r')
-        self.abi = json.load(f)
-        f.close()
-
-        backend = eth_tester.PyEVMBackend(eth_params)
-        self.eth_tester =  eth_tester.EthereumTester(backend)
-        provider = web3.Web3.EthereumTesterProvider(self.eth_tester)
-        self.w3 = web3.Web3(provider)
-        self.sink_address = self.w3.eth.accounts[9]
-
-        c = self.w3.eth.contract(abi=self.abi, bytecode=self.bytecode)
-        tx_hash = c.constructor('Foo Token', 'FOO', 6, TAX_LEVEL * (10 ** 32), PERIOD, self.sink_address).transact({'from': self.w3.eth.accounts[0]})
-
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.contract = self.w3.eth.contract(abi=self.abi, address=r.contractAddress)
-
-        self.start_block = self.w3.eth.blockNumber
-        b = self.w3.eth.getBlock(self.start_block)
-        self.start_time = b['timestamp']
-
-
-    def tearDown(self):
-        pass
-
+class TestPeriod(TestDemurrageDefault):
 
     def test_period(self):
-        tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[1], 1024).transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1024)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        self.eth_tester.time_travel(self.start_time + 61)
-        tx_hash = self.contract.functions.changePeriod().transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
+        self.backend.time_travel(self.start_time + 61)
 
-        redistribution = self.contract.functions.redistributions(1).call()
-        self.assertEqual(2, self.contract.functions.toRedistributionPeriod(redistribution).call())
-        self.assertEqual(2, self.contract.functions.actualPeriod().call())
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.redistributions(self.address, 1, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        redistribution = c.parse_redistributions(r)
+
+        o = c.to_redistribution_period(self.address, redistribution, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        period = c.parse_to_redistribution_period(r)
+        self.assertEqual(2, period)
+
+        o = c.redistributions(self.address, 1, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        redistribution = c.parse_redistributions(r)
+
+        o = c.to_redistribution_period(self.address, redistribution, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        period = c.parse_to_redistribution_period(r)
+        self.assertEqual(2, period)
+
+        o = c.actual_period(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        period = c.parse_actual_period(r)
+        self.assertEqual(2, period)
 
 
 if __name__ == '__main__':

python/tests/test_pure.py

@@ -5,104 +5,66 @@ import json
 import logging
 import math
 
-# third-party imports
-import web3
+# external imports
+from chainlib.eth.constant import ZERO_ADDRESS
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+from chainlib.error import JSONRPCException
 import eth_tester
-import eth_abi
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+
+# test imports
+from tests.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()
 
-logging.getLogger('web3').setLevel(logging.WARNING)
-logging.getLogger('eth.vm').setLevel(logging.WARNING)
-
 testdir = os.path.dirname(__file__)
 
-#BLOCKTIME = 5 # seconds
-TAX_LEVEL = int((10000 * 2) * (10 ** 32)) # 2%
-PERIOD = 10
-
-
-class Test(unittest.TestCase):
-
-    contract = None
-
-    def setUp(self):
-        eth_params = eth_tester.backends.pyevm.main.get_default_genesis_params({
-            'gas_limit': 9000000,
-            })
-
-        f = open(os.path.join(testdir, '../../solidity/RedistributedDemurrageToken.bin'), 'r')
-        self.bytecode = f.read()
-        f.close()
-
-        f = open(os.path.join(testdir, '../../solidity/RedistributedDemurrageToken.json'), 'r')
-        self.abi = json.load(f)
-        f.close()
-
-
-        backend = eth_tester.PyEVMBackend(eth_params)
-        self.eth_tester =  eth_tester.EthereumTester(backend)
-        provider = web3.Web3.EthereumTesterProvider(self.eth_tester)
-        self.w3 = web3.Web3(provider)
-        self.sink_address = self.w3.eth.accounts[9]
-
-        c = self.w3.eth.contract(abi=self.abi, bytecode=self.bytecode)
-        tx_hash = c.constructor('Foo Token', 'FOO', 6, TAX_LEVEL, PERIOD, self.sink_address).transact({'from': self.w3.eth.accounts[0]})
-
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.contract = self.w3.eth.contract(abi=self.abi, address=r.contractAddress)
-
-        self.start_block = self.w3.eth.blockNumber
-
-
-    def tearDown(self):
-        pass
-
-
-    @unittest.skip('this function has been removed from contract')
-    def test_tax_period(self):
-        t = self.contract.functions.taxLevel().call()
-        logg.debug('taxlevel {}'.format(t))
-
-        a = self.contract.functions.toDemurrageAmount(1000000, 0).call()
-        self.assertEqual(a, 1000000)
-
-        a = self.contract.functions.toDemurrageAmount(1000000, 1).call()
-        self.assertEqual(a, 980000)
-
-        a = self.contract.functions.toDemurrageAmount(1000000, 2).call()
-        self.assertEqual(a, 960400)
-
-        a = self.contract.functions.toDemurrageAmount(980000, 1).call()
-        self.assertEqual(a, 960400)
 
+class Test(TestDemurrageDefault):
 
     def test_fractional_state(self):
-        with self.assertRaises(eth_tester.exceptions.TransactionFailed):
-            self.contract.functions.remainder(2, 1).call();
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
 
-        with self.assertRaises(eth_tester.exceptions.TransactionFailed):
-            remainder = self.contract.functions.remainder(0, 100001).call();
+        with self.assertRaises(JSONRPCException):
+            o = c.remainder(self.address, 2, 1, sender_address=self.accounts[0])
+            self.rpc.do(o)
+ 
+        with self.assertRaises(JSONRPCException):
+            o = c.remainder(self.address, 0, 100001, sender_address=self.accounts[0])
+            self.rpc.do(o)       
 
-        remainder = self.contract.functions.remainder(1, 2).call();
+        o = c.remainder(self.address, 1, 2, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        remainder = c.parse_remainder(r)
         self.assertEqual(remainder, 0);
-   
+
         whole = 5000001
         parts = 20000
         expect = whole - (math.floor(whole/parts) * parts) 
-        remainder = self.contract.functions.remainder(parts, whole).call();
+        o = c.remainder(self.address, parts, whole, sender_address=self.accounts[0])
+        r = self.rpc.do(o)      
+        remainder = c.parse_remainder(r)
         self.assertEqual(remainder, expect)
 
         parts = 30000
         expect = whole - (math.floor(whole/parts) * parts) 
-        remainder = self.contract.functions.remainder(parts, whole).call();
+        o = c.remainder(self.address, parts, whole, sender_address=self.accounts[0])
+        r = self.rpc.do(o)      
+        remainder = c.parse_remainder(r)
         self.assertEqual(remainder, expect)
 
         parts = 40001
         expect = whole - (math.floor(whole/parts) * parts) 
-        remainder = self.contract.functions.remainder(parts, whole).call();
+        o = c.remainder(self.address, parts, whole, sender_address=self.accounts[0])
+        r = self.rpc.do(o)      
+        remainder = c.parse_remainder(r)
         self.assertEqual(remainder, expect)
 
+
 if __name__ == '__main__':
     unittest.main()

python/tests/test_redistribution.py

@@ -4,192 +4,257 @@ import unittest
 import json
 import logging
 
-# third-party imports
-import web3
-import eth_tester
-import eth_abi
+# external imports
+from chainlib.eth.constant import ZERO_ADDRESS
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+from chainlib.eth.block import block_latest
+from chainlib.eth.address import to_checksum_address
+from hexathon import (
+        strip_0x,
+        add_0x,
+        )
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+
+# test imports
+from tests.base import TestDemurrageDefault
 
 logging.basicConfig(level=logging.DEBUG)
 logg = logging.getLogger()
 
-logging.getLogger('web3').setLevel(logging.WARNING)
-logging.getLogger('eth.vm').setLevel(logging.WARNING)
-
 testdir = os.path.dirname(__file__)
 
-#BLOCKTIME = 5 # seconds
-TAX_LEVEL = 10000 * 2 # 2%
-#PERIOD = int(60/BLOCKTIME) * 60 * 24 * 30 # month
-PERIOD = 1
+class TestRedistribution(TestDemurrageDefault):
 
+    def test_debug_periods(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
 
-class Test(unittest.TestCase):
+        o = c.actual_period(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        pactual = c.parse_actual_period(r)
 
-    contract = None
+        o = c.period_start(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        pstart = c.parse_actual_period(r)
 
-    def setUp(self):
-        eth_params = eth_tester.backends.pyevm.main.get_default_genesis_params({
-            'gas_limit': 9000000,
-            })
+        o = c.period_duration(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        pduration = c.parse_actual_period(r)
 
-        f = open(os.path.join(testdir, '../../solidity/RedistributedDemurrageToken.bin'), 'r')
-        self.bytecode = f.read()
-        f.close()
+        o = block_latest()
+        blocknumber = self.rpc.do(o)
 
-        f = open(os.path.join(testdir, '../../solidity/RedistributedDemurrageToken.json'), 'r')
-        self.abi = json.load(f)
-        f.close()
-
-        backend = eth_tester.PyEVMBackend(eth_params)
-        self.eth_tester =  eth_tester.EthereumTester(backend)
-        provider = web3.Web3.EthereumTesterProvider(self.eth_tester)
-        self.w3 = web3.Web3(provider)
-        self.sink_address = self.w3.eth.accounts[9]
-
-        c = self.w3.eth.contract(abi=self.abi, bytecode=self.bytecode)
-        tx_hash = c.constructor('Foo Token', 'FOO', 6, TAX_LEVEL * (10 ** 32), PERIOD, self.sink_address).transact({'from': self.w3.eth.accounts[0]})
-
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.contract = self.w3.eth.contract(abi=self.abi, address=r.contractAddress)
-
-        self.start_block = self.w3.eth.blockNumber
-        b = self.w3.eth.getBlock(self.start_block)
-        self.start_time = b['timestamp']
-
-
-    def tearDown(self):
-        pass
-
-
-    def debug_periods(self):
-        pactual = self.contract.functions.actualPeriod().call()
-        pstart = self.contract.functions.periodStart().call()
-        pduration = self.contract.functions.periodDuration().call()
-        blocknumber = self.w3.eth.blockNumber;
         logg.debug('actual {} start {} duration {} blocknumber {}'.format(pactual, pstart, pduration, blocknumber))
 
 
     # TODO: check receipt log outputs
     def test_redistribution_storage(self):
-        redistribution = self.contract.functions.redistributions(0).call();
-        self.assertEqual(redistribution.hex(), '000000000000000000000000f424000000000000000000000000000000000001')
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        o = c.redistributions(self.address, 0, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        self.assertEqual(strip_0x(r), '000000000000000000000000f424000000000000000000000000000000000001')
 
-        self.contract.functions.mintTo(self.w3.eth.accounts[1], 1000000).transact()
-        self.contract.functions.mintTo(self.w3.eth.accounts[2], 1000000).transact()
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 1000000)
+        r = self.rpc.do(o)
 
-        external_address = web3.Web3.toChecksumAddress('0x' + os.urandom(20).hex())
-        tx_hash = self.contract.functions.transfer(external_address, 1000000).transact({'from': self.w3.eth.accounts[2]})
-        tx_hash = self.contract.functions.transfer(external_address, 999999).transact({'from': self.w3.eth.accounts[1]})
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        logg.debug('tx before {}'.format(r))
-        self.assertEqual(r.status, 1)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[2], 1000000)
+        r = self.rpc.do(o)
 
-        self.eth_tester.time_travel(self.start_time + 61)
+        external_address = to_checksum_address('0x' + os.urandom(20).hex())
 
-        redistribution = self.contract.functions.redistributions(0).call();
-        self.assertEqual(redistribution.hex(), '000000000000000000000000f42400000000010000000000001e848000000001')
+        nonce_oracle = RPCNonceOracle(self.accounts[2], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[2], external_address, 1000000)
+        r = self.rpc.do(o)
 
-        tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[0], 1000000).transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(r.status, 1)
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[1], external_address, 999999)
+        r = self.rpc.do(o)
+
+        self.backend.time_travel(self.start_time + self.period_seconds + 1)
+
+        o = c.redistributions(self.address, 0, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        self.assertEqual(strip_0x(r), '000000000000000000000000f42400000000010000000000001e848000000001')
+
+        o = c.redistributions(self.address, 0, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        self.assertEqual(strip_0x(r), '000000000000000000000000f42400000000010000000000001e848000000001')
+
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[0], 1000000)
+        r = self.rpc.do(o)
+
+        o = c.redistributions(self.address, 1, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        self.assertEqual(strip_0x(r), '000000000000000000000000ef4200000000000000000000002dc6c000000002')
 
-        redistribution = self.contract.functions.redistributions(1).call()
-        self.assertEqual(redistribution.hex(), '000000000000000000000000ef4200000000000000000000002dc6c000000002')
-    
 
     def test_redistribution_balance_on_zero_participants(self):
-        supply = 1000000000000
-        tx_hash = self.contract.functions.mintTo(self.w3.eth.accounts[1], supply).transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
+        supply = self.default_supply
 
-        self.eth_tester.time_travel(self.start_time + 61)
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], supply)
+        r = self.rpc.do(o)
 
-        tx_hash = self.contract.functions.applyDemurrage().transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        logg.debug('r {}'.format(r))
-        self.assertEqual(r.status, 1)
-        tx_hash = self.contract.functions.changePeriod().transact()
-        rr = self.w3.eth.getTransactionReceipt(tx_hash)
-        self.assertEqual(rr.status, 1)
+        self.backend.time_travel(self.start_time + self.period_seconds + 1)
+        (tx_hash, o) = c.apply_demurrage(self.address, self.accounts[0])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        rcpt = self.rpc.do(o)
+        self.assertEqual(rcpt['status'], 1)
 
-        redistribution = self.contract.functions.redistributions(0).call();
-        supply = self.contract.functions.totalSupply().call()
+        (tx_hash, o) = c.change_period(self.address, self.accounts[0])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        sink_increment = int(supply * (TAX_LEVEL / 1000000))
-        for l in r['logs']:
-            if l.topics[0].hex() == '0xa0717e54e02bd9829db5e6e998aec0ae9de796b8d150a3cc46a92ab869697755': # event Decayed(uint256,uint256,uint256,uint256)
-                period = int.from_bytes(l.topics[1], 'big')
+        o = c.total_supply(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        total_supply = c.parse_total_supply(r)
+        sink_increment = int(total_supply * (self.tax_level / 1000000))
+        self.assertEqual(supply, total_supply)
+
+        for l in rcpt['logs']:
+            if l['topics'][0] == '0xa0717e54e02bd9829db5e6e998aec0ae9de796b8d150a3cc46a92ab869697755': # event Decayed(uint256,uint256,uint256,uint256)
+                period = int.from_bytes(bytes.fromhex(strip_0x(l['topics'][1])), 'big')
                 self.assertEqual(period, 2)
-                b = bytes.fromhex(l.data[2:])
+                b = bytes.fromhex(strip_0x(l['data']))
                 remainder = int.from_bytes(b, 'big')
-                self.assertEqual(remainder, int((1000000 - TAX_LEVEL) * (10 ** 32)))
-                logg.debug('period {} remainder {}'.format(period, remainder))
+                self.assertEqual(remainder, int((1000000 - self.tax_level) * (10 ** 32)))
+
+        o = c.balance_of(self.address, self.sink_address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        sink_balance = c.parse_balance_of(r)
 
-        sink_balance = self.contract.functions.balanceOf(self.sink_address).call()
-        logg.debug('{} {}'.format(sink_increment, sink_balance))
         self.assertEqual(sink_balance, int(sink_increment * 0.98))
-        self.assertEqual(sink_balance, int(sink_increment * (1000000 - TAX_LEVEL) / 1000000))
+        self.assertEqual(sink_balance, int(sink_increment * (1000000 - self.tax_level) / 1000000))
 
-        balance = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
         self.assertEqual(balance, supply - sink_increment)
 
 
     def test_redistribution_two_of_ten(self):
         mint_amount = 100000000
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
         z = 0
         for i in range(10):
-            self.contract.functions.mintTo(self.w3.eth.accounts[i], mint_amount).transact()
+            (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[i], mint_amount)
+            self.rpc.do(o)
             z += mint_amount
 
-        initial_balance = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        initial_balance = c.parse_balance_of(r)
 
         spend_amount = 1000000
-        external_address = web3.Web3.toChecksumAddress('0x' + os.urandom(20).hex())
-        self.contract.functions.transfer(external_address, spend_amount).transact({'from': self.w3.eth.accounts[1]})
-        tx_hash = self.contract.functions.transfer(external_address, spend_amount).transact({'from': self.w3.eth.accounts[2]})
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
+        external_address = to_checksum_address('0x' + os.urandom(20).hex())
+
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[1], external_address, spend_amount)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[2], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[2], external_address, spend_amount)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
         # No cheating!
-        self.contract.functions.transfer(self.w3.eth.accounts[3], spend_amount).transact({'from': self.w3.eth.accounts[3]})
+        nonce_oracle = RPCNonceOracle(self.accounts[3], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[3], self.accounts[3], spend_amount)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
         # No cheapskating!
-        self.contract.functions.transfer(external_address, spend_amount-1).transact({'from': self.w3.eth.accounts[4]})
+        nonce_oracle = RPCNonceOracle(self.accounts[4], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[4], external_address, spend_amount-1)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        self.assertEqual(r.status, 1)
 
-        self.eth_tester.time_travel(self.start_time + 61)
+        self.backend.time_travel(self.start_time + self.period_seconds + 1)
 
-        self.contract.functions.applyDemurrage().transact()
-        self.contract.functions.changePeriod().transact()
+        (tx_hash, o) = c.apply_demurrage(self.address, self.accounts[4])
+        self.rpc.do(o)
 
-        bummer_balance = self.contract.functions.balanceOf(self.w3.eth.accounts[3]).call()
-        self.assertEqual(bummer_balance, mint_amount - (mint_amount * (TAX_LEVEL / 1000000)))
+        (tx_hash, o) = c.change_period(self.address, self.accounts[4])
+        self.rpc.do(o)
+
+        o = c.balance_of(self.address, self.accounts[3], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bummer_balance = c.parse_balance_of(r)
+
+        self.assertEqual(bummer_balance, mint_amount - (mint_amount * (self.tax_level / 1000000)))
         logg.debug('bal {} '.format(bummer_balance))
 
-        bummer_balance = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        bummer_balance = c.parse_balance_of(r)
         spender_balance = mint_amount - spend_amount
-        spender_decayed_balance = int(spender_balance - (spender_balance * (TAX_LEVEL / 1000000)))
+        spender_decayed_balance = int(spender_balance - (spender_balance * (self.tax_level / 1000000)))
         self.assertEqual(bummer_balance, spender_decayed_balance)
         logg.debug('bal {} '.format(bummer_balance))
 
-        tx_hash = self.contract.functions.applyRedistributionOnAccount(self.w3.eth.accounts[1]).transact()
-        r = self.w3.eth.getTransactionReceipt(tx_hash)
-        logg.debug('log {}'.format(r.logs))
+        (tx_hash, o) = c.apply_redistribution_on_account(self.address, self.accounts[4], self.accounts[1])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        self.contract.functions.applyRedistributionOnAccount(self.w3.eth.accounts[2]).transact()
+#        logg.debug('log {}'.format(r.logs))
+        (tx_hash, o) = c.apply_redistribution_on_account(self.address, self.accounts[4], self.accounts[2])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
 
-        redistribution_data = self.contract.functions.redistributions(0).call()
-        logg.debug('redist data {}'.format(redistribution_data.hex()))
+        o = c.redistributions(self.address, 0, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        redistribution_data = c.parse_redistributions(r)
+        logg.debug('redist data {}'.format(redistribution_data))
 
-        account_period_data = self.contract.functions.accountPeriod(self.w3.eth.accounts[1]).call()
+        o = c.account_period(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        account_period_data = c.parse_account_period(r)
         logg.debug('account period {}'.format(account_period_data))
 
-        actual_period = self.contract.functions.actualPeriod().call()
+        o = c.actual_period(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        actual_period = c.parse_actual_period(r)
         logg.debug('period {}'.format(actual_period))
 
-        redistribution = int((z / 2) * (TAX_LEVEL / 1000000))
+        redistribution = int((z / 2) * (self.tax_level / 1000000))
         spender_new_base_balance = ((mint_amount - spend_amount) + redistribution)
-        spender_new_decayed_balance = int(spender_new_base_balance - (spender_new_base_balance * (TAX_LEVEL / 1000000)))
+        spender_new_decayed_balance = int(spender_new_base_balance - (spender_new_base_balance * (self.tax_level / 1000000)))
 
-        spender_actual_balance = self.contract.functions.balanceOf(self.w3.eth.accounts[1]).call()
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        spender_actual_balance = c.parse_balance_of(r)
         logg.debug('rrr {} {}'.format(redistribution, spender_new_decayed_balance))
 
         self.assertEqual(spender_actual_balance, spender_new_decayed_balance)
@@ -197,5 +262,3 @@ class Test(unittest.TestCase):
 
 if __name__ == '__main__':
     unittest.main()
-
- 

python/tests/test_redistribution_real.py

@@ -0,0 +1,84 @@
+# standard imports
+import os
+import unittest
+import json
+import logging
+
+# external imports
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+
+# test imports
+from tests.base import TestDemurrageReal
+
+logging.basicConfig(level=logging.DEBUG)
+logg = logging.getLogger()
+
+testdir = os.path.dirname(__file__)
+
+
+class TestRedistribution(TestDemurrageReal):
+
+    def test_simple_example(self):
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[1], 100000000)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+        
+        (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[2], 100000000)
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+        
+        nonce_oracle = RPCNonceOracle(self.accounts[1], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[1], self.accounts[3], 50000000)
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        self.backend.time_travel(self.start_time + self.period_seconds + 1)
+
+        (tx_hash, o) = c.change_period(self.address, self.accounts[1])
+        r = self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.redistributions(self.address, 1, sender_address=self.accounts[0])
+        redistribution = self.rpc.do(o)
+        logg.debug('redistribution {}'.format(redistribution))
+
+        o = c.to_redistribution_period(self.address, redistribution, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        period = c.parse_to_redistribution_item(r)
+        logg.debug('period {}'.format(period))
+
+        o = c.to_redistribution_participants(self.address, redistribution, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        participants = c.parse_to_redistribution_item(r)
+        logg.debug('participants {}'.format(participants))
+
+        o = c.to_redistribution_supply(self.address, redistribution, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        supply = c.parse_to_redistribution_item(r)
+        logg.debug('supply {}'.format(supply))
+
+        o = c.to_redistribution_demurrage_modifier(self.address, redistribution, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        modifier = c.parse_to_redistribution_item(r)
+        logg.debug('modifier {}'.format(modifier))
+
+
+
+if __name__ == '__main__':
+    unittest.main()

python/tests/test_single.py

@@ -0,0 +1,95 @@
+import os
+import unittest
+import json
+import logging
+
+# external imports
+from chainlib.eth.constant import ZERO_ADDRESS
+from chainlib.eth.nonce import RPCNonceOracle
+from chainlib.eth.tx import receipt
+from chainlib.eth.block import block_latest
+from chainlib.eth.address import to_checksum_address
+from hexathon import (
+        strip_0x,
+        add_0x,
+        )
+
+# local imports
+from erc20_demurrage_token import DemurrageToken
+
+# test imports
+from tests.base import TestDemurrageSingle
+
+logging.basicConfig(level=logging.DEBUG)
+logg = logging.getLogger()
+
+testdir = os.path.dirname(__file__)
+
+
+class TestRedistributionSingle(TestDemurrageSingle):
+
+    def test_single_even_if_multiple(self):
+
+        mint_amount = 100000000
+
+        nonce_oracle = RPCNonceOracle(self.accounts[0], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+
+        for i in range(3):
+            (tx_hash, o) = c.mint_to(self.address, self.accounts[0], self.accounts[i+1], mint_amount)
+            r = self.rpc.do(o)
+
+        external_address = to_checksum_address('0x' + os.urandom(20).hex())
+        nonce_oracle = RPCNonceOracle(self.accounts[2], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[2], external_address, int(mint_amount) * 0.1)
+        r = self.rpc.do(o)
+
+        nonce_oracle = RPCNonceOracle(self.accounts[3], self.rpc)
+        c = DemurrageToken(self.chain_spec, signer=self.signer, nonce_oracle=nonce_oracle)
+        (tx_hash, o) = c.transfer(self.address, self.accounts[3], external_address, int(mint_amount) * 0.2)
+        r = self.rpc.do(o)
+
+        self.backend.time_travel(self.start_time + self.period_seconds + 1)
+        (tx_hash, o) = c.apply_demurrage(self.address, self.accounts[3])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        rcpt = self.rpc.do(o)
+        self.assertEqual(rcpt['status'], 1)
+
+        (tx_hash, o) = c.change_period(self.address, self.accounts[3])
+        self.rpc.do(o)
+        o = receipt(tx_hash)
+        r = self.rpc.do(o)
+        self.assertEqual(r['status'], 1)
+
+        o = c.balance_of(self.address, self.accounts[1], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        self.assertEqual(balance, mint_amount - (mint_amount * (self.tax_level / 1000000)))
+
+        o = c.balance_of(self.address, self.accounts[2], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        base_amount = mint_amount - int(mint_amount * 0.1)
+        self.assertEqual(balance, (base_amount - (base_amount * (self.tax_level / 1000000))))
+
+        o = c.balance_of(self.address, self.accounts[3], sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        base_amount = mint_amount - int(mint_amount * 0.2)
+        self.assertEqual(balance, (base_amount - (base_amount * (self.tax_level / 1000000))))
+
+        o = c.total_supply(self.address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        new_supply = c.parse_total_supply(r)
+
+        o = c.balance_of(self.address, self.sink_address, sender_address=self.accounts[0])
+        r = self.rpc.do(o)
+        balance = c.parse_balance_of(r)
+        base_amount = new_supply * (self.tax_level / 1000000)
+        self.assertEqual(balance, base_amount - (base_amount * (self.tax_level / 1000000)))
+
+
+if __name__ == '__main__':
+    unittest.main()

solidity/DemurrageTokenMultiCap.sol

@@ -0,0 +1,618 @@
+pragma solidity > 0.6.11;
+
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+contract DemurrageTokenMultiCap {
+
+	// Redistribution bit field, with associated shifts and masks
+	// (Uses sub-byte boundaries)
+	bytes32[] public redistributions; // uint1(isFractional) | uint95(unused) | uint20(demurrageModifier) | uint36(participants) | uint72(value) | uint32(period)
+	uint8 constant shiftRedistributionPeriod 	= 0;
+	uint256 constant maskRedistributionPeriod 	= 0x00000000000000000000000000000000000000000000000000000000ffffffff; // (1 << 32) - 1
+	uint8 constant shiftRedistributionValue 	= 32;
+	uint256 constant maskRedistributionValue	= 0x00000000000000000000000000000000000000ffffffffffffffffff00000000; // ((1 << 72) - 1) << 32
+	uint8 constant shiftRedistributionParticipants	= 104;
+	uint256 constant maskRedistributionParticipants	= 0x00000000000000000000000000000fffffffff00000000000000000000000000; // ((1 << 36) - 1) << 104
+	uint8 constant shiftRedistributionDemurrage	= 140;
+	uint256 constant maskRedistributionDemurrage	= 0x000000000000000000000000fffff00000000000000000000000000000000000; // ((1 << 20) - 1) << 140
+	uint8 constant shiftRedistributionIsFractional	= 255;
+	uint256 constant maskRedistributionIsFractional	= 0x8000000000000000000000000000000000000000000000000000000000000000; // 1 << 255
+
+	// Account bit field, with associated shifts and masks
+	// Mirrors structure of redistributions for consistency
+	mapping (address => bytes32) account; // uint152(unused) | uint32(period) | uint72(value)
+	uint8 constant shiftAccountValue		= 0;
+	uint256 constant maskAccountValue 		= 0x0000000000000000000000000000000000000000000000ffffffffffffffffff; // (1 << 72) - 1
+	uint8 constant shiftAccountPeriod		= 72;
+	uint256 constant maskAccountPeriod 		= 0x00000000000000000000000000000000000000ffffffff000000000000000000; // ((1 << 32) - 1) << 72
+
+	// Cached demurrage amount, ppm with 38 digit resolution
+	uint128 public demurrageAmount;
+
+	// Cached demurrage period; the period for which demurrageAmount was calculated
+	uint128 public demurragePeriod;
+
+	// Implements EIP172
+	address public owner;
+
+	address newOwner;
+
+	// Implements ERC20
+	string public name;
+
+	// Implements ERC20
+	string public symbol;
+
+	// Implements ERC20
+	uint256 public decimals;
+
+	// Implements ERC20
+	uint256 public totalSupply;
+
+	// Maximum amount of tokens that can be minted
+	uint256 public supplyCap;
+
+	// Minimum amount of (demurraged) tokens an account must spend to participate in redistribution for a particular period
+	uint256 public minimumParticipantSpend;
+
+	// 128 bit resolution of the demurrage divisor
+	// (this constant x 1000000 is contained within 128 bits)
+	uint256 constant ppmDivider = 100000000000000000000000000000000;
+
+	// Timestamp of start of periods (time which contract constructor was called)
+	uint256 public immutable periodStart;
+
+	// Duration of a single redistribution period in seconds
+	uint256 public immutable periodDuration;
+
+	// Demurrage in ppm per minute
+	uint256 public immutable taxLevel;
+
+	// Addresses allowed to mint new tokens
+	mapping (address => bool) minter;
+
+	// Storage for ERC20 approve/transferFrom methods
+	mapping (address => mapping (address => uint256 ) ) allowance; // holder -> spender -> amount (amount is subject to demurrage)
+
+	// Address to send unallocated redistribution tokens
+	address sinkAddress; 
+
+	// Implements ERC20
+	event Transfer(address indexed _from, address indexed _to, uint256 _value);
+
+	// Implements ERC20
+	event Approval(address indexed _owner, address indexed _spender, uint256 _value);
+
+	// New tokens minted
+	event Mint(address indexed _minter, address indexed _beneficiary, uint256 _value);
+
+	// New demurrage cache milestone calculated
+	event Decayed(uint256 indexed _period, uint256 indexed _periodCount, uint256 indexed _oldAmount, uint256 _newAmount);
+
+	// When a new period threshold has been crossed
+	event Period(uint256 _period);
+
+	// Redistribution applied on a single eligible account
+	event Redistribution(address indexed _account, uint256 indexed _period, uint256 _value);
+
+	// Temporary event used in development, will be removed on prod
+	event Debug(bytes32 _foo);
+
+	// EIP173
+	event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); // EIP173
+
+	constructor(string memory _name, string memory _symbol, uint8 _decimals, uint256 _taxLevelMinute, uint256 _periodMinutes, address _defaultSinkAddress, uint256 _supplyCap) public {
+		// ACL setup
+		owner = msg.sender;
+		minter[owner] = true;
+
+		// ERC20 setup
+		name = _name;
+		symbol = _symbol;
+		decimals = _decimals;
+
+		// Demurrage setup
+		periodStart = block.timestamp;
+		periodDuration = _periodMinutes * 60;
+		demurrageAmount = uint128(ppmDivider * 1000000); // Represents 38 decimal places
+		demurragePeriod = 1;
+		taxLevel = _taxLevelMinute; // Represents 38 decimal places
+		bytes32 initialRedistribution = toRedistribution(0, 1000000, 0, 1);
+		redistributions.push(initialRedistribution);
+
+		// Misc settings
+		supplyCap = _supplyCap;
+		sinkAddress = _defaultSinkAddress;
+		minimumParticipantSpend = 10 ** uint256(_decimals);
+	}
+
+	// Given address will be allowed to call the mintTo() function
+	function addMinter(address _minter) public returns (bool) {
+		require(msg.sender == owner);
+		minter[_minter] = true;
+		return true;
+	}
+
+	// Given address will no longer be allowed to call the mintTo() function
+	function removeMinter(address _minter) public returns (bool) {
+		require(msg.sender == owner || _minter == msg.sender);
+		minter[_minter] = false;
+		return true;
+	}
+
+	/// Implements ERC20
+	function balanceOf(address _account) public view returns (uint256) {
+		uint256 baseBalance;
+		uint256 currentDemurragedAmount;
+		uint256 periodCount;
+
+		baseBalance = baseBalanceOf(_account);
+
+		periodCount = actualPeriod() - demurragePeriod; 
+
+		currentDemurragedAmount = uint128(decayBy(demurrageAmount, periodCount));
+
+		return (baseBalance * currentDemurragedAmount) / (ppmDivider * 1000000);
+	}
+
+	/// Balance unmodified by demurrage
+	function baseBalanceOf(address _account) public view returns (uint256) {
+		return uint256(account[_account]) & maskAccountValue;
+	}
+
+	/// Increases base balance for a single account
+	function increaseBaseBalance(address _account, uint256 _delta) private returns (bool) {
+		uint256 oldBalance;
+		uint256 newBalance;
+		uint256 workAccount;
+
+		workAccount = uint256(account[_account]);
+	
+		if (_delta == 0) {
+			return false;
+		}
+
+		oldBalance = baseBalanceOf(_account);
+		newBalance = oldBalance + _delta;
+		require(uint160(newBalance) > uint160(oldBalance), 'ERR_WOULDWRAP'); // revert if increase would result in a wrapped value
+		workAccount &= (~maskAccountValue); 
+		workAccount |= (newBalance & maskAccountValue);
+		account[_account] = bytes32(workAccount);
+		return true;
+	}
+
+	/// Decreases base balance for a single account
+	function decreaseBaseBalance(address _account, uint256 _delta) private returns (bool) {
+		uint256 oldBalance;
+	       	uint256 newBalance;
+		uint256 workAccount;
+
+		workAccount = uint256(account[_account]);
+
+		if (_delta == 0) {
+			return false;
+		}
+
+		oldBalance = baseBalanceOf(_account);	
+		require(oldBalance >= _delta, 'ERR_OVERSPEND'); // overspend guard
+		newBalance = oldBalance - _delta;
+		workAccount &= (~maskAccountValue);
+		workAccount |= (newBalance & maskAccountValue);
+		account[_account] = bytes32(workAccount);
+		return true;
+	}
+
+	// Creates new tokens out of thin air, and allocates them to the given address
+	// Triggers tax
+	function mintTo(address _beneficiary, uint256 _amount) external returns (bool) {
+		uint256 baseAmount;
+
+		require(minter[msg.sender]);
+		require(_amount + totalSupply <= supplyCap);
+
+		changePeriod();
+		baseAmount = _amount;
+		totalSupply += _amount;
+		increaseBaseBalance(_beneficiary, baseAmount);
+		emit Mint(msg.sender, _beneficiary, _amount);
+		saveRedistributionSupply();
+		return true;
+	}
+
+	// Deserializes the redistribution word
+	// uint1(isFractional) | uint95(unused) | uint20(demurrageModifier) | uint36(participants) | uint72(value) | uint32(period)
+	function toRedistribution(uint256 _participants, uint256 _demurrageModifierPpm, uint256 _value, uint256 _period) private pure returns(bytes32) {
+		bytes32 redistribution;
+
+		redistribution |= bytes32((_demurrageModifierPpm << shiftRedistributionDemurrage) & maskRedistributionDemurrage);
+		redistribution |= bytes32((_participants << shiftRedistributionParticipants) & maskRedistributionParticipants);
+		redistribution |= bytes32((_value << shiftRedistributionValue) & maskRedistributionValue); 
+		redistribution |= bytes32(_period & maskRedistributionPeriod);
+		return redistribution;
+	}
+
+	// Serializes the demurrage period part of the redistribution word
+	function toRedistributionPeriod(bytes32 redistribution) public pure returns (uint256) {
+		return uint256(redistribution) & maskRedistributionPeriod;
+	}
+
+	// Serializes the supply part of the redistribution word
+	function toRedistributionSupply(bytes32 redistribution) public pure returns (uint256) {
+		return (uint256(redistribution) & maskRedistributionValue) >> shiftRedistributionValue;
+	}
+
+	// Serializes the number of participants part of the redistribution word
+	function toRedistributionParticipants(bytes32 redistribution) public pure returns (uint256) {
+		return (uint256(redistribution) & maskRedistributionParticipants) >> shiftRedistributionParticipants;
+	}
+
+	// Serializes the demurrage modifier part of the redistribution word
+	function toRedistributionDemurrageModifier(bytes32 redistribution) public pure returns (uint256) {
+		return (uint256(redistribution) & maskRedistributionDemurrage) >> shiftRedistributionDemurrage;
+	}
+
+	// Client accessor to the redistributions array length
+	function redistributionCount() public view returns (uint256) {
+		return redistributions.length;
+	}
+
+	// Add number of participants for the current redistribution period by one
+	function incrementRedistributionParticipants() private returns (bool) {
+		bytes32 currentRedistribution;
+		uint256 tmpRedistribution;
+		uint256 participants;
+
+		currentRedistribution = redistributions[redistributions.length-1];
+		participants = toRedistributionParticipants(currentRedistribution) + 1;
+		tmpRedistribution = uint256(currentRedistribution);
+		tmpRedistribution &= (~maskRedistributionParticipants);
+		tmpRedistribution |= ((participants << shiftRedistributionParticipants) & maskRedistributionParticipants);
+
+		redistributions[redistributions.length-1] = bytes32(tmpRedistribution);
+
+		return true;
+	}
+
+	// Save the current total supply amount to the current redistribution period
+	function saveRedistributionSupply() private returns (bool) {
+		uint256 currentRedistribution;
+
+		currentRedistribution = uint256(redistributions[redistributions.length-1]);
+		currentRedistribution &= (~maskRedistributionValue);
+		currentRedistribution |= (totalSupply << shiftRedistributionValue);
+
+		redistributions[redistributions.length-1] = bytes32(currentRedistribution);
+		return true;
+	}
+
+	// Get the demurrage period of the current block number
+	function actualPeriod() public view returns (uint128) {
+		return uint128((block.timestamp - periodStart) / periodDuration + 1);
+	}
+
+	// Add an entered demurrage period to the redistribution array
+	function checkPeriod() private view returns (bytes32) {
+		bytes32 lastRedistribution;
+		uint256 currentPeriod;
+
+		lastRedistribution =  redistributions[redistributions.length-1];
+		currentPeriod = this.actualPeriod();
+		if (currentPeriod <= toRedistributionPeriod(lastRedistribution)) {
+			return bytes32(0x00);
+		}
+		return lastRedistribution;
+	}
+
+	// Deserialize the pemurrage period for the given account is participating in
+	function accountPeriod(address _account) public view returns (uint256) {
+		return (uint256(account[_account]) & maskAccountPeriod) >> shiftAccountPeriod;
+	}
+
+	// Save the given demurrage period as the currently participation period for the given address
+	function registerAccountPeriod(address _account, uint256 _period) private returns (bool) {
+		account[_account] &= bytes32(~maskAccountPeriod);
+		account[_account] |= bytes32((_period << shiftAccountPeriod) & maskAccountPeriod);
+		incrementRedistributionParticipants();
+		return true;
+	}
+
+	// Determine whether the unit number is rounded down, rounded up or evenly divides.
+	// Returns 0 if evenly distributed, or the remainder as a positive number
+	// A _numParts value 0 will be interpreted as the value 1
+	function remainder(uint256 _numParts, uint256 _sumWhole) public pure returns (uint256) {
+		uint256 unit;
+		uint256 truncatedResult;
+
+		if (_numParts == 0) { // no division by zero please
+			revert('ERR_NUMPARTS_ZERO');
+		}
+		require(_numParts < _sumWhole); // At least you are never LESS than the sum of your parts. Think about that.
+
+		unit = _sumWhole / _numParts;
+		truncatedResult = unit * _numParts;
+		return _sumWhole - truncatedResult;
+	}
+
+	// Called in the edge case where participant number is 0. It will override the participant count to 1.
+	// Returns the remainder sent to the sink address
+	function applyDefaultRedistribution(bytes32 _redistribution) private returns (uint256) {
+		uint256 redistributionSupply;
+		uint256 redistributionPeriod;
+		uint256 unit;
+		uint256 truncatedResult;
+
+		redistributionSupply = toRedistributionSupply(_redistribution);
+
+		unit = (redistributionSupply * taxLevel) / 1000000;
+		truncatedResult = (unit * 1000000) / taxLevel;
+
+		if (truncatedResult < redistributionSupply) {
+			redistributionPeriod = toRedistributionPeriod(_redistribution); // since we reuse period here, can possibly be optimized by passing period instead
+			redistributions[redistributionPeriod-1] &= bytes32(~maskRedistributionParticipants); // just to be safe, zero out all participant count data, in this case there will be only one
+			redistributions[redistributionPeriod-1] |= bytes32(maskRedistributionIsFractional | (1 << shiftRedistributionParticipants));
+		}
+
+		increaseBaseBalance(sinkAddress, unit / ppmDivider);
+		return unit;
+	}
+
+	// sets the remainder bit for the given period and books the remainder to the sink address balance
+	// returns false if no change was made
+	function applyRemainderOnPeriod(uint256 _remainder, uint256 _period) private returns (bool) {
+		uint256 periodSupply;
+
+		if (_remainder == 0) {
+			return false;
+		}
+
+		// TODO: is this needed?
+		redistributions[_period-1] |= bytes32(maskRedistributionIsFractional);
+
+		periodSupply = toRedistributionSupply(redistributions[_period-1]);
+		increaseBaseBalance(sinkAddress, periodSupply - _remainder);
+		return true;
+	}
+
+
+	// Calculate and cache the demurrage value corresponding to the (period of the) time of the method call
+	function applyDemurrage() public returns (bool) {
+		uint128 epochPeriodCount;
+		uint128 periodCount;
+		uint256 lastDemurrageAmount;
+		uint256 newDemurrageAmount;
+
+		epochPeriodCount = actualPeriod();
+		periodCount = epochPeriodCount - demurragePeriod;
+		if (periodCount == 0) {
+			return false;
+		}
+		lastDemurrageAmount = demurrageAmount;
+		demurrageAmount = uint128(decayBy(lastDemurrageAmount, periodCount));
+		demurragePeriod = epochPeriodCount; 
+		emit Decayed(epochPeriodCount, periodCount, lastDemurrageAmount, demurrageAmount);
+		return true;
+	}
+
+	// Return timestamp of start of period threshold
+	function getPeriodTimeDelta(uint256 _periodCount) public view returns (uint256) {
+		return periodStart + (_periodCount * periodDuration);
+	}
+
+	// Amount of demurrage cycles inbetween the current timestamp and the given target time
+	function demurrageCycles(uint256 _target) public view returns (uint256) {
+		return (block.timestamp - _target) / 60;
+	}
+
+	// Recalculate the demurrage modifier for the new period
+	// After this, all REPORTED balances will have been reduced by the corresponding ratio (but the effecive totalsupply stays the same)
+	function changePeriod() public returns (bool) {
+		bytes32 currentRedistribution;
+		bytes32 nextRedistribution;
+		uint256 currentPeriod;
+		uint256 currentParticipants;
+		uint256 currentRemainder;
+		uint256 currentDemurrageAmount;
+		uint256 nextRedistributionDemurrage;
+		uint256 demurrageCounts;
+		uint256 periodTimestamp;
+		uint256 nextPeriod;
+
+		applyDemurrage();
+
+		currentRedistribution = checkPeriod();
+		if (currentRedistribution == bytes32(0x00)) {
+			return false;
+		}
+
+		currentPeriod = toRedistributionPeriod(currentRedistribution);
+		nextPeriod = currentPeriod + 1;
+		periodTimestamp = getPeriodTimeDelta(currentPeriod);
+
+		//applyDemurrage();
+		currentDemurrageAmount = demurrageAmount; 
+
+		demurrageCounts = demurrageCycles(periodTimestamp);
+		if (demurrageCounts > 0) {
+			nextRedistributionDemurrage = growBy(currentDemurrageAmount, demurrageCounts) / ppmDivider;
+		} else {
+			nextRedistributionDemurrage = currentDemurrageAmount / ppmDivider;
+		}
+		
+		nextRedistribution = toRedistribution(0, nextRedistributionDemurrage, totalSupply, nextPeriod);
+		redistributions.push(nextRedistribution);
+
+		currentParticipants = toRedistributionParticipants(currentRedistribution);
+		if (currentParticipants == 0) {
+			currentRemainder = applyDefaultRedistribution(currentRedistribution);
+		} else {
+			currentRemainder = remainder(currentParticipants, totalSupply); // we can use totalSupply directly because it will always be the same as the recorded supply on the current redistribution
+			applyRemainderOnPeriod(currentRemainder, currentPeriod);
+		}
+		emit Period(nextPeriod);
+		return true;
+	}
+
+	// Reverse a value reduced by demurrage by the given period to its original value
+	function growBy(uint256 _value, uint256 _period) public view returns (uint256) {
+		uint256 valueFactor;
+		uint256 truncatedTaxLevel;
+	      
+		valueFactor = 1000000;
+		truncatedTaxLevel = taxLevel / ppmDivider;
+
+		for (uint256 i = 0; i < _period; i++) {
+			valueFactor = valueFactor + ((valueFactor * truncatedTaxLevel) / 1000000);
+		}
+		return (valueFactor * _value) / 1000000;
+	}
+
+	// Calculate a value reduced by demurrage by the given period
+	// TODO: higher precision if possible
+	function decayBy(uint256 _value, uint256 _period) public view returns (uint256) {
+		uint256 valueFactor;
+		uint256 truncatedTaxLevel;
+	      
+		valueFactor = 1000000;
+		truncatedTaxLevel = taxLevel / ppmDivider;
+
+		for (uint256 i = 0; i < _period; i++) {
+			valueFactor = valueFactor - ((valueFactor * truncatedTaxLevel) / 1000000);
+		}
+		return (valueFactor * _value) / 1000000;
+	}
+
+	// If the given account is participating in a period and that period has been crossed
+	// THEN increase the base value of the account with its share of the value reduction of the period
+	function applyRedistributionOnAccount(address _account) public returns (bool) {
+		bytes32 periodRedistribution;
+		uint256 supply;
+		uint256 participants;
+		uint256 baseValue;
+		uint256 value;
+		uint256 period;
+		uint256 demurrage;
+	       
+		period = accountPeriod(_account);
+		if (period == 0 || period >= actualPeriod()) {
+			return false;
+		}
+		periodRedistribution = redistributions[period-1];
+		participants = toRedistributionParticipants(periodRedistribution);
+		if (participants == 0) {
+			return false;
+		}
+
+		supply = toRedistributionSupply(periodRedistribution);
+		demurrage = toRedistributionDemurrageModifier(periodRedistribution);
+		baseValue = ((supply / participants) * (taxLevel / 1000000)) / ppmDivider;
+		value = (baseValue * demurrage) / 1000000;
+
+		// zero out period for the account
+		account[_account] &= bytes32(~maskAccountPeriod); 
+		increaseBaseBalance(_account, value);
+
+		emit Redistribution(_account, period, value);
+		return true;
+	}
+
+	// Inflates the given amount according to the current demurrage modifier
+	function toBaseAmount(uint256 _value) public view returns (uint256) {
+		//return (_value * ppmDivider * 1000000) / toDemurrageAmount(demurrageModifier);
+		return (_value * ppmDivider * 1000000) / demurrageAmount;
+	}
+
+	// Implements ERC20, triggers tax and/or redistribution
+	function approve(address _spender, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+
+		changePeriod();
+		applyRedistributionOnAccount(msg.sender);
+
+		baseValue = toBaseAmount(_value);
+		allowance[msg.sender][_spender] += baseValue;
+		emit Approval(msg.sender, _spender, _value);
+		return true;
+	}
+
+	// Implements ERC20, triggers tax and/or redistribution
+	function transfer(address _to, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+		bool result;
+
+		changePeriod();
+		applyRedistributionOnAccount(msg.sender);
+
+		baseValue = toBaseAmount(_value);
+		result = transferBase(msg.sender, _to, baseValue);
+		emit Transfer(msg.sender, _to, _value);
+		return result;
+	}
+
+
+	// Implements ERC20, triggers tax and/or redistribution
+	function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+		bool result;
+
+		changePeriod();
+		applyRedistributionOnAccount(msg.sender);
+
+		baseValue = toBaseAmount(_value);
+		require(allowance[_from][msg.sender] >= baseValue);
+
+		result = transferBase(_from, _to, baseValue);
+		emit Transfer(_from, _to, _value);
+		return result;
+	}
+
+	// ERC20 transfer backend for transfer, transferFrom
+	function transferBase(address _from, address _to, uint256 _value) private returns (bool) {
+		uint256 period;
+
+		decreaseBaseBalance(_from, _value);
+		increaseBaseBalance(_to, _value);
+
+		period = actualPeriod();
+		if (_value >= minimumParticipantSpend && accountPeriod(_from) != period && _from != _to) {
+			registerAccountPeriod(_from, period);
+		}
+		return true;
+	}
+
+	// Implements EIP173
+	function transferOwnership(address _newOwner) public returns (bool) {
+		require(msg.sender == owner);
+		newOwner = _newOwner;
+	}
+
+	// Implements OwnedAccepter
+	function acceptOwnership() public returns (bool) {
+		address oldOwner;
+
+		require(msg.sender == newOwner);
+		oldOwner = owner; 
+		owner = newOwner;
+		newOwner = address(0);
+		emit OwnershipTransferred(oldOwner, owner);
+	}
+
+	// Implements EIP165
+	function supportsInterface(bytes4 _sum) public pure returns (bool) {
+		if (_sum == 0xc6bb4b70) { // ERC20
+			return true;
+		}
+		if (_sum == 0x449a52f8) { // Minter
+			return true;
+		}
+		if (_sum == 0x01ffc9a7) { // EIP165
+			return true;
+		}
+		if (_sum == 0x9493f8b2) { // EIP173
+			return true;
+		}
+		if (_sum == 0x37a47be4) { // OwnedAccepter
+			return true;
+		}
+		return false;
+	}
+}

solidity/DemurrageTokenMultiNocap.sol

@@ -2,7 +2,7 @@ pragma solidity > 0.6.11;
 
 // SPDX-License-Identifier: GPL-3.0-or-later
 
-contract RedistributedDemurrageToken {
+contract DemurrageTokenMultiNocap {
 
 	// Redistribution bit field, with associated shifts and masks
 	// (Uses sub-byte boundaries)
@@ -35,6 +35,8 @@ contract RedistributedDemurrageToken {
 	// Implements EIP172
 	address public owner;
 
+	address newOwner;
+
 	// Implements ERC20
 	string public name;
 
@@ -93,6 +95,9 @@ contract RedistributedDemurrageToken {
 	// Temporary event used in development, will be removed on prod
 	event Debug(bytes32 _foo);
 
+	// EIP173
+	event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); // EIP173
+
 	constructor(string memory _name, string memory _symbol, uint8 _decimals, uint256 _taxLevelMinute, uint256 _periodMinutes, address _defaultSinkAddress) public {
 		// ACL setup
 		owner = msg.sender;
@@ -509,7 +514,7 @@ contract RedistributedDemurrageToken {
 		return (_value * ppmDivider * 1000000) / demurrageAmount;
 	}
 
-	// ERC20, triggers tax and/or redistribution
+	// Implements ERC20, triggers tax and/or redistribution
 	function approve(address _spender, uint256 _value) public returns (bool) {
 		uint256 baseValue;
 
@@ -522,7 +527,7 @@ contract RedistributedDemurrageToken {
 		return true;
 	}
 
-	// ERC20, triggers tax and/or redistribution
+	// Implements ERC20, triggers tax and/or redistribution
 	function transfer(address _to, uint256 _value) public returns (bool) {
 		uint256 baseValue;
 		bool result;
@@ -537,7 +542,7 @@ contract RedistributedDemurrageToken {
 	}
 
 
-	// ERC20, triggers tax and/or redistribution
+	// Implements ERC20, triggers tax and/or redistribution
 	function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
 		uint256 baseValue;
 		bool result;
@@ -566,4 +571,41 @@ contract RedistributedDemurrageToken {
 		}
 		return true;
 	}
+
+	// Implements EIP173
+	function transferOwnership(address _newOwner) public returns (bool) {
+		require(msg.sender == owner);
+		newOwner = _newOwner;
+	}
+
+	// Implements OwnedAccepter
+	function acceptOwnership() public returns (bool) {
+		address oldOwner;
+
+		require(msg.sender == newOwner);
+		oldOwner = owner; 
+		owner = newOwner;
+		newOwner = address(0);
+		emit OwnershipTransferred(oldOwner, owner);
+	}
+
+	// Implements EIP165
+	function supportsInterface(bytes4 _sum) public pure returns (bool) {
+		if (_sum == 0xc6bb4b70) { // ERC20
+			return true;
+		}
+		if (_sum == 0x449a52f8) { // Minter
+			return true;
+		}
+		if (_sum == 0x01ffc9a7) { // EIP165
+			return true;
+		}
+		if (_sum == 0x9493f8b2) { // EIP173
+			return true;
+		}
+		if (_sum == 0x37a47be4) { // OwnedAccepter
+			return true;
+		}
+		return false;
+	}
 }

solidity/DemurrageTokenSingleCap.sol

@@ -0,0 +1,475 @@
+pragma solidity > 0.6.11;
+
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+contract DemurrageTokenSingleCap {
+
+	// Redistribution bit field, with associated shifts and masks
+	// (Uses sub-byte boundaries)
+	bytes32[] public redistributions; // uint95(unused) | uint20(demurrageModifier) | uint36(participants) | uint72(value) | uint32(period)
+	uint8 constant shiftRedistributionPeriod 	= 0;
+	uint256 constant maskRedistributionPeriod 	= 0x00000000000000000000000000000000000000000000000000000000ffffffff; // (1 << 32) - 1
+	uint8 constant shiftRedistributionValue 	= 32;
+	uint256 constant maskRedistributionValue	= 0x00000000000000000000000000000000000000ffffffffffffffffff00000000; // ((1 << 72) - 1) << 32
+	uint8 constant shiftRedistributionDemurrage	= 140;
+	uint256 constant maskRedistributionDemurrage	= 0x000000000000000000000000fffff00000000000000000000000000000000000; // ((1 << 20) - 1) << 140
+
+	// Account balances
+	mapping (address => uint256) account;
+	
+	// Cached demurrage amount, ppm with 38 digit resolution
+	uint128 public demurrageAmount;
+
+	// Cached demurrage period; the period for which demurrageAmount was calculated
+	uint128 public demurragePeriod;
+
+	// Implements EIP172
+	address public owner;
+
+	address newOwner;
+
+	// Implements ERC20
+	string public name;
+
+	// Implements ERC20
+	string public symbol;
+
+	// Implements ERC20
+	uint256 public decimals;
+
+	// Implements ERC20
+	uint256 public totalSupply;
+
+	// Maximum amount of tokens that can be minted
+	uint256 public supplyCap;
+
+	// Minimum amount of (demurraged) tokens an account must spend to participate in redistribution for a particular period
+	uint256 public minimumParticipantSpend;
+
+	// 128 bit resolution of the demurrage divisor
+	// (this constant x 1000000 is contained within 128 bits)
+	uint256 constant ppmDivider = 100000000000000000000000000000000;
+
+	// Timestamp of start of periods (time which contract constructor was called)
+	uint256 public immutable periodStart;
+
+	// Duration of a single redistribution period in seconds
+	uint256 public immutable periodDuration;
+
+	// Demurrage in ppm per minute
+	uint256 public immutable taxLevel;
+
+	// Addresses allowed to mint new tokens
+	mapping (address => bool) minter;
+
+	// Storage for ERC20 approve/transferFrom methods
+	mapping (address => mapping (address => uint256 ) ) allowance; // holder -> spender -> amount (amount is subject to demurrage)
+
+	// Address to send unallocated redistribution tokens
+	address sinkAddress; 
+
+	// Implements ERC20
+	event Transfer(address indexed _from, address indexed _to, uint256 _value);
+
+	// Implements ERC20
+	event Approval(address indexed _owner, address indexed _spender, uint256 _value);
+
+	// New tokens minted
+	event Mint(address indexed _minter, address indexed _beneficiary, uint256 _value);
+
+	// New demurrage cache milestone calculated
+	event Decayed(uint256 indexed _period, uint256 indexed _periodCount, uint256 indexed _oldAmount, uint256 _newAmount);
+
+	// When a new period threshold has been crossed
+	event Period(uint256 _period);
+
+	// Redistribution applied on a single eligible account
+	event Redistribution(address indexed _account, uint256 indexed _period, uint256 _value);
+
+	// Temporary event used in development, will be removed on prod
+	event Debug(bytes32 _foo);
+
+	// EIP173
+	event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); // EIP173
+
+	constructor(string memory _name, string memory _symbol, uint8 _decimals, uint256 _taxLevelMinute, uint256 _periodMinutes, address _defaultSinkAddress, uint256 _supplyCap) public {
+		// ACL setup
+		owner = msg.sender;
+		minter[owner] = true;
+
+		// ERC20 setup
+		name = _name;
+		symbol = _symbol;
+		decimals = _decimals;
+
+		// Demurrage setup
+		periodStart = block.timestamp;
+		periodDuration = _periodMinutes * 60;
+		demurrageAmount = uint128(ppmDivider * 1000000); // Represents 38 decimal places
+		demurragePeriod = 1;
+		taxLevel = _taxLevelMinute; // Represents 38 decimal places
+		bytes32 initialRedistribution = toRedistribution(0, 1000000, 0, 1);
+		redistributions.push(initialRedistribution);
+
+		// Misc settings
+		supplyCap = _supplyCap;
+		sinkAddress = _defaultSinkAddress;
+		minimumParticipantSpend = 10 ** uint256(_decimals);
+	}
+
+	// Given address will be allowed to call the mintTo() function
+	function addMinter(address _minter) public returns (bool) {
+		require(msg.sender == owner);
+		minter[_minter] = true;
+		return true;
+	}
+
+	// Given address will no longer be allowed to call the mintTo() function
+	function removeMinter(address _minter) public returns (bool) {
+		require(msg.sender == owner || _minter == msg.sender);
+		minter[_minter] = false;
+		return true;
+	}
+
+	/// Implements ERC20
+	function balanceOf(address _account) public view returns (uint256) {
+		uint256 baseBalance;
+		uint256 currentDemurragedAmount;
+		uint256 periodCount;
+
+		baseBalance = baseBalanceOf(_account);
+
+		periodCount = actualPeriod() - demurragePeriod; 
+
+		currentDemurragedAmount = uint128(decayBy(demurrageAmount, periodCount));
+
+		return (baseBalance * currentDemurragedAmount) / (ppmDivider * 1000000);
+	}
+
+	/// Balance unmodified by demurrage
+	function baseBalanceOf(address _account) public view returns (uint256) {
+		return account[_account];
+	}
+
+	/// Increases base balance for a single account
+	function increaseBaseBalance(address _account, uint256 _delta) private returns (bool) {
+		uint256 oldBalance;
+		uint256 newBalance;
+		uint256 workAccount;
+
+		workAccount = uint256(account[_account]);
+	
+		if (_delta == 0) {
+			return false;
+		}
+
+		oldBalance = baseBalanceOf(_account);
+		account[_account] = oldBalance + _delta;
+		return true;
+	}
+
+	/// Decreases base balance for a single account
+	function decreaseBaseBalance(address _account, uint256 _delta) private returns (bool) {
+		uint256 oldBalance;
+	       	uint256 newBalance;
+		uint256 workAccount;
+
+		workAccount = uint256(account[_account]);
+
+		if (_delta == 0) {
+			return false;
+		}
+
+		oldBalance = baseBalanceOf(_account);	
+		require(oldBalance >= _delta, 'ERR_OVERSPEND'); // overspend guard
+		account[_account] = oldBalance - _delta;
+		return true;
+	}
+
+	// Creates new tokens out of thin air, and allocates them to the given address
+	// Triggers tax
+	function mintTo(address _beneficiary, uint256 _amount) external returns (bool) {
+		uint256 baseAmount;
+
+		require(minter[msg.sender], 'ERR_ACCESS');
+		require(_amount + totalSupply <= supplyCap, 'ERR_CAP');
+
+		changePeriod();
+		baseAmount = _amount;
+		totalSupply += _amount;
+		increaseBaseBalance(_beneficiary, baseAmount);
+		emit Mint(msg.sender, _beneficiary, _amount);
+		saveRedistributionSupply();
+		return true;
+	}
+
+	// Deserializes the redistribution word
+	// uint95(unused) | uint20(demurrageModifier) | uint36(participants) | uint72(value) | uint32(period)
+	function toRedistribution(uint256 _participants, uint256 _demurrageModifierPpm, uint256 _value, uint256 _period) private pure returns(bytes32) {
+		bytes32 redistribution;
+
+		redistribution |= bytes32((_demurrageModifierPpm << shiftRedistributionDemurrage) & maskRedistributionDemurrage);
+		redistribution |= bytes32((_value << shiftRedistributionValue) & maskRedistributionValue); 
+		redistribution |= bytes32(_period & maskRedistributionPeriod);
+		return redistribution;
+	}
+
+	// Serializes the demurrage period part of the redistribution word
+	function toRedistributionPeriod(bytes32 redistribution) public pure returns (uint256) {
+		return uint256(redistribution) & maskRedistributionPeriod;
+	}
+
+	// Serializes the supply part of the redistribution word
+	function toRedistributionSupply(bytes32 redistribution) public pure returns (uint256) {
+		return (uint256(redistribution) & maskRedistributionValue) >> shiftRedistributionValue;
+	}
+
+	// Serializes the number of participants part of the redistribution word
+	function toRedistributionDemurrageModifier(bytes32 redistribution) public pure returns (uint256) {
+		return (uint256(redistribution) & maskRedistributionDemurrage) >> shiftRedistributionDemurrage;
+	}
+
+	// Client accessor to the redistributions array length
+	function redistributionCount() public view returns (uint256) {
+		return redistributions.length;
+	}
+
+	// Save the current total supply amount to the current redistribution period
+	function saveRedistributionSupply() private returns (bool) {
+		uint256 currentRedistribution;
+
+		currentRedistribution = uint256(redistributions[redistributions.length-1]);
+		currentRedistribution &= (~maskRedistributionValue);
+		currentRedistribution |= (totalSupply << shiftRedistributionValue);
+
+		redistributions[redistributions.length-1] = bytes32(currentRedistribution);
+		return true;
+	}
+
+	// Get the demurrage period of the current block number
+	function actualPeriod() public view returns (uint128) {
+		return uint128((block.timestamp - periodStart) / periodDuration + 1);
+	}
+
+	// Add an entered demurrage period to the redistribution array
+	function checkPeriod() private view returns (bytes32) {
+		bytes32 lastRedistribution;
+		uint256 currentPeriod;
+
+		lastRedistribution =  redistributions[redistributions.length-1];
+		currentPeriod = this.actualPeriod();
+		if (currentPeriod <= toRedistributionPeriod(lastRedistribution)) {
+			return bytes32(0x00);
+		}
+		return lastRedistribution;
+	}
+
+	// Returns the amount sent to the sink address
+	function applyDefaultRedistribution(bytes32 _redistribution) private returns (uint256) {
+		uint256 redistributionSupply;
+		uint256 redistributionPeriod;
+		uint256 unit;
+		uint256 truncatedResult;
+
+		redistributionSupply = toRedistributionSupply(_redistribution);
+
+		unit = (redistributionSupply * taxLevel) / 1000000;
+		truncatedResult = (unit * 1000000) / taxLevel;
+
+		if (truncatedResult < redistributionSupply) {
+			redistributionPeriod = toRedistributionPeriod(_redistribution); // since we reuse period here, can possibly be optimized by passing period instead
+		}
+
+		increaseBaseBalance(sinkAddress, unit / ppmDivider);
+		return unit;
+	}
+
+	// Calculate and cache the demurrage value corresponding to the (period of the) time of the method call
+	function applyDemurrage() public returns (bool) {
+		uint128 epochPeriodCount;
+		uint128 periodCount;
+		uint256 lastDemurrageAmount;
+		uint256 newDemurrageAmount;
+
+		epochPeriodCount = actualPeriod();
+		periodCount = epochPeriodCount - demurragePeriod;
+		if (periodCount == 0) {
+			return false;
+		}
+		lastDemurrageAmount = demurrageAmount;
+		demurrageAmount = uint128(decayBy(lastDemurrageAmount, periodCount));
+		demurragePeriod = epochPeriodCount; 
+		emit Decayed(epochPeriodCount, periodCount, lastDemurrageAmount, demurrageAmount);
+		return true;
+	}
+
+	// Return timestamp of start of period threshold
+	function getPeriodTimeDelta(uint256 _periodCount) public view returns (uint256) {
+		return periodStart + (_periodCount * periodDuration);
+	}
+
+	// Amount of demurrage cycles inbetween the current timestamp and the given target time
+	function demurrageCycles(uint256 _target) public view returns (uint256) {
+		return (block.timestamp - _target) / 60;
+	}
+
+	// Recalculate the demurrage modifier for the new period
+	function changePeriod() public returns (bool) {
+		bytes32 currentRedistribution;
+		bytes32 nextRedistribution;
+		uint256 currentPeriod;
+		uint256 currentDemurrageAmount;
+		uint256 nextRedistributionDemurrage;
+		uint256 demurrageCounts;
+		uint256 periodTimestamp;
+		uint256 nextPeriod;
+
+		currentRedistribution = checkPeriod();
+		if (currentRedistribution == bytes32(0x00)) {
+			return false;
+		}
+
+		currentPeriod = toRedistributionPeriod(currentRedistribution);
+		nextPeriod = currentPeriod + 1;
+		periodTimestamp = getPeriodTimeDelta(currentPeriod);
+
+		applyDemurrage();
+		currentDemurrageAmount = demurrageAmount; 
+
+		demurrageCounts = demurrageCycles(periodTimestamp);
+		if (demurrageCounts > 0) {
+			nextRedistributionDemurrage = growBy(currentDemurrageAmount, demurrageCounts) / ppmDivider;
+		} else {
+			nextRedistributionDemurrage = currentDemurrageAmount / ppmDivider;
+		}
+		
+		nextRedistribution = toRedistribution(0, nextRedistributionDemurrage, totalSupply, nextPeriod);
+		redistributions.push(nextRedistribution);
+
+		applyDefaultRedistribution(currentRedistribution);
+		emit Period(nextPeriod);
+		return true;
+	}
+
+	// Reverse a value reduced by demurrage by the given period to its original value
+	function growBy(uint256 _value, uint256 _period) public view returns (uint256) {
+		uint256 valueFactor;
+		uint256 truncatedTaxLevel;
+	      
+		valueFactor = 1000000;
+		truncatedTaxLevel = taxLevel / ppmDivider;
+
+		for (uint256 i = 0; i < _period; i++) {
+			valueFactor = valueFactor + ((valueFactor * truncatedTaxLevel) / 1000000);
+		}
+		return (valueFactor * _value) / 1000000;
+	}
+
+	// Calculate a value reduced by demurrage by the given period
+	// TODO: higher precision if possible
+	function decayBy(uint256 _value, uint256 _period) public view returns (uint256) {
+		uint256 valueFactor;
+		uint256 truncatedTaxLevel;
+	      
+		valueFactor = 1000000;
+		truncatedTaxLevel = taxLevel / ppmDivider;
+
+		for (uint256 i = 0; i < _period; i++) {
+			valueFactor = valueFactor - ((valueFactor * truncatedTaxLevel) / 1000000);
+		}
+		return (valueFactor * _value) / 1000000;
+	}
+
+	// Inflates the given amount according to the current demurrage modifier
+	function toBaseAmount(uint256 _value) public view returns (uint256) {
+		return (_value * ppmDivider * 1000000) / demurrageAmount;
+	}
+
+	// Implements ERC20, triggers tax and/or redistribution
+	function approve(address _spender, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+
+		changePeriod();
+
+		baseValue = toBaseAmount(_value);
+		allowance[msg.sender][_spender] += baseValue;
+		emit Approval(msg.sender, _spender, _value);
+		return true;
+	}
+
+	// Implements ERC20, triggers tax and/or redistribution
+	function transfer(address _to, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+		bool result;
+
+		changePeriod();
+
+		baseValue = toBaseAmount(_value);
+		result = transferBase(msg.sender, _to, baseValue);
+		emit Transfer(msg.sender, _to, _value);
+		return result;
+	}
+
+	// Implements ERC20, triggers tax and/or redistribution
+	function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+		bool result;
+
+		changePeriod();
+
+		baseValue = toBaseAmount(_value);
+		require(allowance[_from][msg.sender] >= baseValue);
+
+		result = transferBase(_from, _to, baseValue);
+		emit Transfer(_from, _to, _value);
+		return result;
+	}
+
+	// ERC20 transfer backend for transfer, transferFrom
+	function transferBase(address _from, address _to, uint256 _value) private returns (bool) {
+		uint256 period;
+
+		decreaseBaseBalance(_from, _value);
+		increaseBaseBalance(_to, _value);
+
+		period = actualPeriod();
+		return true;
+	}
+
+	// Implements EIP173
+	function transferOwnership(address _newOwner) public returns (bool) {
+		require(msg.sender == owner);
+		newOwner = _newOwner;
+	}
+
+	// Implements OwnedAccepter
+	function acceptOwnership() public returns (bool) {
+		address oldOwner;
+
+		require(msg.sender == newOwner);
+		oldOwner = owner; 
+		owner = newOwner;
+		newOwner = address(0);
+		emit OwnershipTransferred(oldOwner, owner);
+	}
+
+	// Implements EIP165
+	function supportsInterface(bytes4 _sum) public pure returns (bool) {
+		if (_sum == 0xc6bb4b70) { // ERC20
+			return true;
+		}
+		if (_sum == 0x449a52f8) { // Minter
+			return true;
+		}
+		if (_sum == 0x01ffc9a7) { // EIP165
+			return true;
+		}
+		if (_sum == 0x9493f8b2) { // EIP173
+			return true;
+		}
+		if (_sum == 0x37a47be4) { // OwnedAccepter
+			return true;
+		}
+		return false;
+	}
+}

solidity/DemurrageTokenSingleNocap.sol

@@ -0,0 +1,471 @@
+pragma solidity > 0.6.11;
+
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+contract DemurrageTokenSingleNocap {
+
+	// Redistribution bit field, with associated shifts and masks
+	// (Uses sub-byte boundaries)
+	bytes32[] public redistributions; // uint95(unused) | uint20(demurrageModifier) | uint36(participants) | uint72(value) | uint32(period)
+	uint8 constant shiftRedistributionPeriod 	= 0;
+	uint256 constant maskRedistributionPeriod 	= 0x00000000000000000000000000000000000000000000000000000000ffffffff; // (1 << 32) - 1
+	uint8 constant shiftRedistributionValue 	= 32;
+	uint256 constant maskRedistributionValue	= 0x00000000000000000000000000000000000000ffffffffffffffffff00000000; // ((1 << 72) - 1) << 32
+	uint8 constant shiftRedistributionDemurrage	= 140;
+	uint256 constant maskRedistributionDemurrage	= 0x000000000000000000000000fffff00000000000000000000000000000000000; // ((1 << 20) - 1) << 140
+
+	// Account balances
+	mapping (address => uint256) account;
+	
+	// Cached demurrage amount, ppm with 38 digit resolution
+	uint128 public demurrageAmount;
+
+	// Cached demurrage period; the period for which demurrageAmount was calculated
+	uint128 public demurragePeriod;
+
+	// Implements EIP172
+	address public owner;
+
+	address newOwner;
+
+	// Implements ERC20
+	string public name;
+
+	// Implements ERC20
+	string public symbol;
+
+	// Implements ERC20
+	uint256 public decimals;
+
+	// Implements ERC20
+	uint256 public totalSupply;
+
+	// Minimum amount of (demurraged) tokens an account must spend to participate in redistribution for a particular period
+	uint256 public minimumParticipantSpend;
+
+	// 128 bit resolution of the demurrage divisor
+	// (this constant x 1000000 is contained within 128 bits)
+	uint256 constant ppmDivider = 100000000000000000000000000000000;
+
+	// Timestamp of start of periods (time which contract constructor was called)
+	uint256 public immutable periodStart;
+
+	// Duration of a single redistribution period in seconds
+	uint256 public immutable periodDuration;
+
+	// Demurrage in ppm per minute
+	uint256 public immutable taxLevel;
+
+	// Addresses allowed to mint new tokens
+	mapping (address => bool) minter;
+
+	// Storage for ERC20 approve/transferFrom methods
+	mapping (address => mapping (address => uint256 ) ) allowance; // holder -> spender -> amount (amount is subject to demurrage)
+
+	// Address to send unallocated redistribution tokens
+	address sinkAddress; 
+
+	// Implements ERC20
+	event Transfer(address indexed _from, address indexed _to, uint256 _value);
+
+	// Implements ERC20
+	event Approval(address indexed _owner, address indexed _spender, uint256 _value);
+
+	// New tokens minted
+	event Mint(address indexed _minter, address indexed _beneficiary, uint256 _value);
+
+	// New demurrage cache milestone calculated
+	event Decayed(uint256 indexed _period, uint256 indexed _periodCount, uint256 indexed _oldAmount, uint256 _newAmount);
+
+	// When a new period threshold has been crossed
+	event Period(uint256 _period);
+
+	// Redistribution applied on a single eligible account
+	event Redistribution(address indexed _account, uint256 indexed _period, uint256 _value);
+
+	// Temporary event used in development, will be removed on prod
+	event Debug(bytes32 _foo);
+
+	// EIP173
+	event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); // EIP173
+
+	constructor(string memory _name, string memory _symbol, uint8 _decimals, uint256 _taxLevelMinute, uint256 _periodMinutes, address _defaultSinkAddress) public {
+		// ACL setup
+		owner = msg.sender;
+		minter[owner] = true;
+
+		// ERC20 setup
+		name = _name;
+		symbol = _symbol;
+		decimals = _decimals;
+
+		// Demurrage setup
+		periodStart = block.timestamp;
+		periodDuration = _periodMinutes * 60;
+		demurrageAmount = uint128(ppmDivider * 1000000); // Represents 38 decimal places
+		demurragePeriod = 1;
+		taxLevel = _taxLevelMinute; // Represents 38 decimal places
+		bytes32 initialRedistribution = toRedistribution(0, 1000000, 0, 1);
+		redistributions.push(initialRedistribution);
+
+		// Misc settings
+		sinkAddress = _defaultSinkAddress;
+		minimumParticipantSpend = 10 ** uint256(_decimals);
+	}
+
+	// Given address will be allowed to call the mintTo() function
+	function addMinter(address _minter) public returns (bool) {
+		require(msg.sender == owner);
+		minter[_minter] = true;
+		return true;
+	}
+
+	// Given address will no longer be allowed to call the mintTo() function
+	function removeMinter(address _minter) public returns (bool) {
+		require(msg.sender == owner || _minter == msg.sender);
+		minter[_minter] = false;
+		return true;
+	}
+
+	/// Implements ERC20
+	function balanceOf(address _account) public view returns (uint256) {
+		uint256 baseBalance;
+		uint256 currentDemurragedAmount;
+		uint256 periodCount;
+
+		baseBalance = baseBalanceOf(_account);
+
+		periodCount = actualPeriod() - demurragePeriod; 
+
+		currentDemurragedAmount = uint128(decayBy(demurrageAmount, periodCount));
+
+		return (baseBalance * currentDemurragedAmount) / (ppmDivider * 1000000);
+	}
+
+	/// Balance unmodified by demurrage
+	function baseBalanceOf(address _account) public view returns (uint256) {
+		return account[_account];
+	}
+
+	/// Increases base balance for a single account
+	function increaseBaseBalance(address _account, uint256 _delta) private returns (bool) {
+		uint256 oldBalance;
+		uint256 newBalance;
+		uint256 workAccount;
+
+		workAccount = uint256(account[_account]);
+	
+		if (_delta == 0) {
+			return false;
+		}
+
+		oldBalance = baseBalanceOf(_account);
+		account[_account] = oldBalance + _delta;
+		return true;
+	}
+
+	/// Decreases base balance for a single account
+	function decreaseBaseBalance(address _account, uint256 _delta) private returns (bool) {
+		uint256 oldBalance;
+	       	uint256 newBalance;
+		uint256 workAccount;
+
+		workAccount = uint256(account[_account]);
+
+		if (_delta == 0) {
+			return false;
+		}
+
+		oldBalance = baseBalanceOf(_account);	
+		require(oldBalance >= _delta, 'ERR_OVERSPEND'); // overspend guard
+		account[_account] = oldBalance - _delta;
+		return true;
+	}
+
+	// Creates new tokens out of thin air, and allocates them to the given address
+	// Triggers tax
+	function mintTo(address _beneficiary, uint256 _amount) external returns (bool) {
+		uint256 baseAmount;
+
+		require(minter[msg.sender]);
+
+		changePeriod();
+		baseAmount = _amount;
+		totalSupply += _amount;
+		increaseBaseBalance(_beneficiary, baseAmount);
+		emit Mint(msg.sender, _beneficiary, _amount);
+		saveRedistributionSupply();
+		return true;
+	}
+
+	// Deserializes the redistribution word
+	// uint95(unused) | uint20(demurrageModifier) | uint36(participants) | uint72(value) | uint32(period)
+	function toRedistribution(uint256 _participants, uint256 _demurrageModifierPpm, uint256 _value, uint256 _period) private pure returns(bytes32) {
+		bytes32 redistribution;
+
+		redistribution |= bytes32((_demurrageModifierPpm << shiftRedistributionDemurrage) & maskRedistributionDemurrage);
+		redistribution |= bytes32((_value << shiftRedistributionValue) & maskRedistributionValue); 
+		redistribution |= bytes32(_period & maskRedistributionPeriod);
+		return redistribution;
+	}
+
+	// Serializes the demurrage period part of the redistribution word
+	function toRedistributionPeriod(bytes32 redistribution) public pure returns (uint256) {
+		return uint256(redistribution) & maskRedistributionPeriod;
+	}
+
+	// Serializes the supply part of the redistribution word
+	function toRedistributionSupply(bytes32 redistribution) public pure returns (uint256) {
+		return (uint256(redistribution) & maskRedistributionValue) >> shiftRedistributionValue;
+	}
+
+	// Serializes the number of participants part of the redistribution word
+	function toRedistributionDemurrageModifier(bytes32 redistribution) public pure returns (uint256) {
+		return (uint256(redistribution) & maskRedistributionDemurrage) >> shiftRedistributionDemurrage;
+	}
+
+	// Client accessor to the redistributions array length
+	function redistributionCount() public view returns (uint256) {
+		return redistributions.length;
+	}
+
+	// Save the current total supply amount to the current redistribution period
+	function saveRedistributionSupply() private returns (bool) {
+		uint256 currentRedistribution;
+
+		currentRedistribution = uint256(redistributions[redistributions.length-1]);
+		currentRedistribution &= (~maskRedistributionValue);
+		currentRedistribution |= (totalSupply << shiftRedistributionValue);
+
+		redistributions[redistributions.length-1] = bytes32(currentRedistribution);
+		return true;
+	}
+
+	// Get the demurrage period of the current block number
+	function actualPeriod() public view returns (uint128) {
+		return uint128((block.timestamp - periodStart) / periodDuration + 1);
+	}
+
+	// Add an entered demurrage period to the redistribution array
+	function checkPeriod() private view returns (bytes32) {
+		bytes32 lastRedistribution;
+		uint256 currentPeriod;
+
+		lastRedistribution =  redistributions[redistributions.length-1];
+		currentPeriod = this.actualPeriod();
+		if (currentPeriod <= toRedistributionPeriod(lastRedistribution)) {
+			return bytes32(0x00);
+		}
+		return lastRedistribution;
+	}
+
+	// Returns the amount sent to the sink address
+	function applyDefaultRedistribution(bytes32 _redistribution) private returns (uint256) {
+		uint256 redistributionSupply;
+		uint256 redistributionPeriod;
+		uint256 unit;
+		uint256 truncatedResult;
+
+		redistributionSupply = toRedistributionSupply(_redistribution);
+
+		unit = (redistributionSupply * taxLevel) / 1000000;
+		truncatedResult = (unit * 1000000) / taxLevel;
+
+		if (truncatedResult < redistributionSupply) {
+			redistributionPeriod = toRedistributionPeriod(_redistribution); // since we reuse period here, can possibly be optimized by passing period instead
+		}
+
+		increaseBaseBalance(sinkAddress, unit / ppmDivider);
+		return unit;
+	}
+
+	// Calculate and cache the demurrage value corresponding to the (period of the) time of the method call
+	function applyDemurrage() public returns (bool) {
+		uint128 epochPeriodCount;
+		uint128 periodCount;
+		uint256 lastDemurrageAmount;
+		uint256 newDemurrageAmount;
+
+		epochPeriodCount = actualPeriod();
+		periodCount = epochPeriodCount - demurragePeriod;
+		if (periodCount == 0) {
+			return false;
+		}
+		lastDemurrageAmount = demurrageAmount;
+		demurrageAmount = uint128(decayBy(lastDemurrageAmount, periodCount));
+		demurragePeriod = epochPeriodCount; 
+		emit Decayed(epochPeriodCount, periodCount, lastDemurrageAmount, demurrageAmount);
+		return true;
+	}
+
+	// Return timestamp of start of period threshold
+	function getPeriodTimeDelta(uint256 _periodCount) public view returns (uint256) {
+		return periodStart + (_periodCount * periodDuration);
+	}
+
+	// Amount of demurrage cycles inbetween the current timestamp and the given target time
+	function demurrageCycles(uint256 _target) public view returns (uint256) {
+		return (block.timestamp - _target) / 60;
+	}
+
+	// Recalculate the demurrage modifier for the new period
+	function changePeriod() public returns (bool) {
+		bytes32 currentRedistribution;
+		bytes32 nextRedistribution;
+		uint256 currentPeriod;
+		uint256 currentDemurrageAmount;
+		uint256 nextRedistributionDemurrage;
+		uint256 demurrageCounts;
+		uint256 periodTimestamp;
+		uint256 nextPeriod;
+
+		currentRedistribution = checkPeriod();
+		if (currentRedistribution == bytes32(0x00)) {
+			return false;
+		}
+
+		currentPeriod = toRedistributionPeriod(currentRedistribution);
+		nextPeriod = currentPeriod + 1;
+		periodTimestamp = getPeriodTimeDelta(currentPeriod);
+
+		applyDemurrage();
+		currentDemurrageAmount = demurrageAmount; 
+
+		demurrageCounts = demurrageCycles(periodTimestamp);
+		if (demurrageCounts > 0) {
+			nextRedistributionDemurrage = growBy(currentDemurrageAmount, demurrageCounts) / ppmDivider;
+		} else {
+			nextRedistributionDemurrage = currentDemurrageAmount / ppmDivider;
+		}
+		
+		nextRedistribution = toRedistribution(0, nextRedistributionDemurrage, totalSupply, nextPeriod);
+		redistributions.push(nextRedistribution);
+
+		applyDefaultRedistribution(currentRedistribution);
+		emit Period(nextPeriod);
+		return true;
+	}
+
+	// Reverse a value reduced by demurrage by the given period to its original value
+	function growBy(uint256 _value, uint256 _period) public view returns (uint256) {
+		uint256 valueFactor;
+		uint256 truncatedTaxLevel;
+	      
+		valueFactor = 1000000;
+		truncatedTaxLevel = taxLevel / ppmDivider;
+
+		for (uint256 i = 0; i < _period; i++) {
+			valueFactor = valueFactor + ((valueFactor * truncatedTaxLevel) / 1000000);
+		}
+		return (valueFactor * _value) / 1000000;
+	}
+
+	// Calculate a value reduced by demurrage by the given period
+	// TODO: higher precision if possible
+	function decayBy(uint256 _value, uint256 _period) public view returns (uint256) {
+		uint256 valueFactor;
+		uint256 truncatedTaxLevel;
+	      
+		valueFactor = 1000000;
+		truncatedTaxLevel = taxLevel / ppmDivider;
+
+		for (uint256 i = 0; i < _period; i++) {
+			valueFactor = valueFactor - ((valueFactor * truncatedTaxLevel) / 1000000);
+		}
+		return (valueFactor * _value) / 1000000;
+	}
+
+	// Inflates the given amount according to the current demurrage modifier
+	function toBaseAmount(uint256 _value) public view returns (uint256) {
+		return (_value * ppmDivider * 1000000) / demurrageAmount;
+	}
+
+	// Implements ERC20, triggers tax and/or redistribution
+	function approve(address _spender, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+
+		changePeriod();
+
+		baseValue = toBaseAmount(_value);
+		allowance[msg.sender][_spender] += baseValue;
+		emit Approval(msg.sender, _spender, _value);
+		return true;
+	}
+
+	// Implements ERC20, triggers tax and/or redistribution
+	function transfer(address _to, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+		bool result;
+
+		changePeriod();
+
+		baseValue = toBaseAmount(_value);
+		result = transferBase(msg.sender, _to, baseValue);
+		emit Transfer(msg.sender, _to, _value);
+		return result;
+	}
+
+
+	// Implements ERC20, triggers tax and/or redistribution
+	function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
+		uint256 baseValue;
+		bool result;
+
+		changePeriod();
+
+		baseValue = toBaseAmount(_value);
+		require(allowance[_from][msg.sender] >= baseValue);
+
+		result = transferBase(_from, _to, baseValue);
+		emit Transfer(_from, _to, _value);
+		return result;
+	}
+
+	// ERC20 transfer backend for transfer, transferFrom
+	function transferBase(address _from, address _to, uint256 _value) private returns (bool) {
+		uint256 period;
+
+		decreaseBaseBalance(_from, _value);
+		increaseBaseBalance(_to, _value);
+
+		period = actualPeriod();
+		return true;
+	}
+
+	// Implements EIP173
+	function transferOwnership(address _newOwner) public returns (bool) {
+		require(msg.sender == owner);
+		newOwner = _newOwner;
+	}
+
+	// Implements OwnedAccepter
+	function acceptOwnership() public returns (bool) {
+		address oldOwner;
+
+		require(msg.sender == newOwner);
+		oldOwner = owner; 
+		owner = newOwner;
+		newOwner = address(0);
+		emit OwnershipTransferred(oldOwner, owner);
+	}
+
+	// Implements EIP165
+	function supportsInterface(bytes4 _sum) public pure returns (bool) {
+		if (_sum == 0xc6bb4b70) { // ERC20
+			return true;
+		}
+		if (_sum == 0x449a52f8) { // Minter
+			return true;
+		}
+		if (_sum == 0x01ffc9a7) { // EIP165
+			return true;
+		}
+		if (_sum == 0x9493f8b2) { // EIP173
+			return true;
+		}
+		if (_sum == 0x37a47be4) { // OwnedAccepter
+			return true;
+		}
+		return false;
+	}
+}

solidity/Makefile

@@ -1,16 +1,38 @@
 SOLC = /usr/bin/solc
 
-all:
-	$(SOLC) RedistributedDemurrageToken.sol --abi --evm-version byzantium | awk 'NR>3' > RedistributedDemurrageToken.json
-	$(SOLC) RedistributedDemurrageToken.sol --bin --evm-version byzantium | awk 'NR>3' > RedistributedDemurrageToken.bin
-	truncate -s -1 RedistributedDemurrageToken.bin
+all: multi single
+
+multi_nocap:
+	$(SOLC) DemurrageTokenMultiNocap.sol --abi --evm-version byzantium | awk 'NR>3' > DemurrageTokenMultiNocap.json
+	$(SOLC) DemurrageTokenMultiNocap.sol --bin --evm-version byzantium | awk 'NR>3' > DemurrageTokenMultiNocap.bin
+	truncate -s -1 DemurrageTokenMultiNocap.bin
+
+multi_cap:
+	$(SOLC) DemurrageTokenMultiCap.sol --abi --evm-version byzantium | awk 'NR>3' > DemurrageTokenMultiCap.json
+	$(SOLC) DemurrageTokenMultiCap.sol --bin --evm-version byzantium | awk 'NR>3' > DemurrageTokenMultiCap.bin
+	truncate -s -1 DemurrageTokenMultiCap.bin
+
+multi: multi_nocap multi_cap
+
+single_nocap:
+	$(SOLC) DemurrageTokenSingleNocap.sol --abi --evm-version byzantium | awk 'NR>3' > DemurrageTokenSingleNocap.json
+	$(SOLC) DemurrageTokenSingleNocap.sol --bin --evm-version byzantium | awk 'NR>3' > DemurrageTokenSingleNocap.bin
+	truncate -s -1 DemurrageTokenSingleNocap.bin
+
+single_cap:
+	$(SOLC) DemurrageTokenSingleCap.sol --abi --evm-version byzantium | awk 'NR>3' > DemurrageTokenSingleCap.json
+	$(SOLC) DemurrageTokenSingleCap.sol --bin --evm-version byzantium | awk 'NR>3' > DemurrageTokenSingleCap.bin
+	truncate -s -1 DemurrageTokenSingleCap.bin
+
+single: single_nocap single_cap
 
 test: all
 	python ../python/tests/test_basic.py
 	python ../python/tests/test_period.py
 	python ../python/tests/test_redistribution.py
+	python ../python/tests/test_pure.py
 
 install: all
-	cp -v RedistributedDemurrageToken.{json,bin} ../python/sarafu_token/data/
+	cp -v DemurrageToken*.{json,bin} ../python/erc20_demurrage_token/data/
 	
 .PHONY: test install