This is outdated: The ERC-20 is here: ethereum/EIPs#20
function totalSupply() constant returns (uint256 supply)
Get the total coin supply
function balanceOf(address _address) constant returns (uint256 balance)
Get the account balance of another account with address _address
function transfer(address _to, uint256 _value) returns (bool _success)
Send _value
amount of coins to address _to
function transferFrom(address _from, address _to, uint256 _value) returns (bool success)
Send _value
amount of coins from address _from
to address _to
The transferFrom
method is used for a "direct debit" workflow, allowing contracts to send coins on your behalf, for example to "deposit" to a contract address and/or to charge fees in sub-currencies; the command should fail unless the _from
account has deliberately authorized the sender of the message via some mechanism; we propose these standardized APIs for approval:
function approve(address _address) returns (bool success)
Allow _address
to direct debit from your account with full custody. Only implement if absolutely required and use carefully. See approveOnce
below for a more limited method.
function unapprove(address _address) returns (bool success)
Unapprove address _address
to direct debit from your account if it was previously approved. Must reset both one-time and full custody approvals.
function isApprovedFor(address _target, address _proxy) constant returns (bool success)
Returns 1 if _proxy
is allowed to direct debit from _target
function approveOnce(address _address, uint256 _maxValue) returns (bool success)
Makes a one-time approval for _address
to send a maximum amount of currency equal to _maxValue
function isApprovedOnceFor(address _target, address _proxy) returns (uint256 maxValue)
Returns _maxValue
if _proxy
is allowed to direct debit the returned maxValue
from address _target
only once. The approval must be reset on any transfer by _proxy
of _maxValue
or less.
event Transfer(address indexed _from, address indexed _to, uint256 _value)
Triggered when tokens are transferred.
event AddressApproval(address indexed _address, address indexed _proxy, bool _result)
Triggered when an _address
approves _proxy
to direct debit from their account.
event AddressApprovalOnce(address indexed _address, address indexed _proxy, uint256 _value)
Triggered when an _address
approves _proxy
to direct debit from their account only once for a maximum of _value
Yeah,
createCheque
andcashCheque
as above, plustransferCheque(address _from, address _to, uint256 _value)
sounds good. In that case, we should probably remove the_to
argument fromcashCheque
; generally, you can only cash cheques from your own bank account.We probably also want
getChequeValue(address _from, address _for)
. We then have a choice of whether we want to keep thevalue
argument incashCheque
rather than simply only allowing cashing in 100% of whatever is in there. If we want to fully follow the cheque analogy, this triad seems most intuitive to me:function createCheque(address _for, uint256 _maxValue)
function cashCheque(address _from)
function getChequeValue(address _from, address _for)
Question: does running
createCheque
twice add the value of the two cheques together? Are there legitimate use cases for creating a cheque multiple times and then cashing either once or multiple times?