erc20-limiter

ERC20 balance limit registry
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README.md (1827B)

      1 # erc20-limiter
      2 
      3 These smart contract implementations define value limits for tokens by holders.
      4 
      5 The contracts satisfy the [CIC TokenLimit](https://git.grassecon.net/cicnet/cic-contracts/#tokenlimit) interface.
      6 
      7 
      8 ## Defining limits
      9 
     10 The `setLimit(token, value)` method set the limit of `token` that the transaction signer will accept to `value`.
     11 
     12 Values are _inclusive_; if `42` is returned, a balance up to and including `42` should be approved.
     13 
     14 A limit of `0` means that the "holder" will categorically not accept a token.
     15 
     16 
     17 ### Defining limits for contracts
     18 
     19 An alternative `setLimitFor(token, holder, value)` method exists, where the contract `owner` may change the limit for a _smart contract_.
     20 
     21 If smart contract capable of transacting against this method itself does so, the result is the same as if that contract called `setLimit()`.
     22 
     23 The `owner` for the contract defined and managed according to the [ERC173](https://eips.ethereum.org/EIPS/eip-173) standard.
     24 
     25 
     26 ## Honoring limits
     27 
     28 Limits will only be honored if integrated into the proper context.
     29 
     30 One example of context is to implement a limit check in the `transfer` and `transferFrom` methods of ERC20 tokens.
     31 
     32 
     33 ## ACL Index variant
     34 
     35 The `LimitIndex.sol` contract variant includes an implementation of the [CIC ACL](https://git.grassecon.net/cicnet/cic-contracts/#acl) interface.
     36 
     37 In this case, any non-zero limit of a token for a holder results in a `true` value being returned. Otherwise, `false` is returned.
     38 
     39 The `LimitIndex.sol` contract takes a regular `Limit.sol` token address as argument, or more specifically a contract that satisfies this interface:
     40 
     41 ```
     42 interface Limiter {
     43 	function limitOf(address,address) external view returns(uint256);
     44 	function setLimit(address,uint256) external;
     45 	function setLimitFor(address,address,uint256) external;
     46 }
     47 ```