> For the complete documentation index, see [llms.txt](https://docs.t-rex.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.t-rex.network/reference/token-suite/modularcompliance.md). # ModularCompliance `ModularCompliance` is the second gate of an asset and its ledger of positions. It answers the token before a movement, records the movement after it, routes each question to the modules the Issuer bound, and keeps what every identity owns over all its addresses and all chains. The concepts are in [Modular compliance](/token-and-register/modular-compliance.md) and [The compliance ledger](/token-and-register/the-compliance-ledger.md). The functions that issue and settle cross-chain validations are part of the same contract. They are listed in [Transfer validation](/reference/token-suite/transfer-validation.md). ### At a glance | | | | --------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Source** | `contracts/compliance/modular/ModularCompliance.sol`, with `ComplianceLedger.sol` and `TransferValidation.sol`, on the standard base `ERC3643Compliance` | | **Interfaces** | `IModularCompliance`, `IERC3643Compliance`, `IComplianceLedger`, `ITransferValidation`, `ISettlementHandler` | | **Deployed as** | A beacon proxy per asset, bound to one token | | **Limits** | 25 modules. 5 setting calls in one `addAndSetModule` | ### Called by the token | Function | Access | Behavior | | ------------------------------------------------ | --------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `canTransfer(_from, _to, _amount)` | Anyone, read | True when the amount is at most the smallest amount any `RULE` module allows. True with no `RULE` module. While a rule is bound, false when the sender or the recipient resolves to no identity | | `canSpenderCall(_spender, _from, _to, _value)` | Anyone, read | True when every `SPENDER` module accepts the spender. True with no `SPENDER` module | | `transferred(_from, _to, _amount)` | The bound token | Moves the amount between the positions of the two identities, then calls `afterTransfer` on every `TRACKER` module. Reverts with `ZeroValue`, `ZeroAddress` | | `created(_to, _amount)` | The bound token | The same for a mint | | `destroyed(_from, _amount)` | The bound token | The same for a burn | | `handleSettlement(originChainKey, notification)` | The bound token | Applies a settlement notification from a satellite: see [Transfer validation](/reference/token-suite/transfer-validation.md) | A call from another address than the bound token reverts with `AddressNotATokenBoundToComplianceContract`. ### Token binding | Function | Access | Reverts with | | ------------------------------------------------------------------- | ---------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------ | | `bindToken(_token)` | The token itself while no token is bound, or `OWNER` | `OnlyOwnerOrTokenCanCall`, `ZeroAddress`, `TokenCirculating` when the token has supply. Emits `TokenBound` | | `unbindToken(_token)` | The token, or `OWNER` | `OnlyOwnerOrTokenCanCall`, `ZeroAddress`, `TokenNotBound`. Emits `TokenUnbound` | | `getTokenBound()`, `isTokenBound(_token)` | Anyone, read | | | `init(tokenAddress, accessManagerAddress, modules, moduleSettings)` | Initializer, called once by the factory | `ZeroAddress`, `InvalidCompliancePattern` when there are more settings than modules, and the errors of `addModule` | ### Modules | Function | Access | Reverts with | | ------------------------------------------------------------------------ | ------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `addModule(_module)` | `OWNER` | `ZeroAddress`, `MaxModulesReached`, `ModuleAlreadyBound`, `ComplianceNotSuitableForBindingToModule`, `ModuleHasNoType`, `DuplicateModuleType`. Emits `ModuleTypesRecorded` and `ModuleAdded` | | `addAndSetModule(_module, _interactions)` | `OWNER` | `ArraySizeLimited` above five calls, then the errors of `addModule` and of each setting call. Emits `ModuleInteraction` for each call | | `callModuleFunction(callData, _module)` | `OWNER` | `ModuleNotBound`, and any revert of the module. The module sees the compliance as the caller. Emits `ModuleInteraction` | | `removeModule(_module)` | `OWNER` | `ZeroAddress`, `ModuleNotBound`, and any revert of the module's `unbindCompliance`. Emits `ModuleRemoved` | | `forceRemoveModule(_module)` | `OWNER` | `ZeroAddress`, `ModuleNotBound`. Makes no call to the module. Emits `ModuleForceRemoved` and no `ModuleRemoved`. The module keeps its record of the binding, so the same module address cannot be bound to this compliance again | | `resyncModuleTypes(_module)` | `OWNER` | `ModuleNotBound`, `ModuleHasNoType`, `DuplicateModuleType`. Reads `moduleTypes()` again after an upgrade of the module. Emits `ModuleTypesRecorded` | | `isModuleBound(_module)`, `getModules()`, `getModulesByType(moduleType)` | Anyone, read | | Guides: [11 Add a compliance rule](/guides/issuer/11.-add-a-compliance-rule.md), [12 Remove a compliance rule](/guides/issuer/12.-remove-a-compliance-rule.md), [26 Authorize spenders](/guides/issuer/26.-authorize-spenders.md). ### The ledger | Function | Access | Returns or does | | ------------------------------- | ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `positionOf(identity)` | Anyone, read | What the identity owns, over all its addresses and all chains | | `pendingInOf(identity)` | Anyone, read | What open validations promise to the identity | | `pendingOutOf(identity)` | Anyone, read | What open validations promise out of it | | `ownerOf(wallet)` | Anyone, read | The identity the ledger credits for an address of the reference chain. It can lag the registry until the next movement through that address | | `positionGap()` | Anyone, read | An `int256`: the amounts the ledger could not attribute to an identity. Zero in a consistent ledger | | `fixPosition(from, to, amount)` | `OWNER` | Moves `amount` of position from one identity to another. The zero address stands for the gap. Reverts with `FromAndToAreTheSame`, `InsufficientPosition`. Emits `PositionFixed` | A normal movement changes positions without an event. The ledger emits only on exceptions: `WalletOwnerChanged`, `PositionUnresolved`, `PositionUnderflow`. ### Events | Event | Emitted when | | ------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------ | | `TokenBound(address _token)`, `TokenUnbound(address _token)` | The compliance is bound to its token, unbound | | `ModuleAdded(address indexed module)`, `ModuleRemoved`, `ModuleForceRemoved` (same argument) | A module is bound, removed, removed without being called | | `ModuleTypesRecorded(address indexed module, IModule.ModuleType[] moduleTypes)` | A module is filed under its types | | `ModuleInteraction(address indexed target, bytes data)` | A setting of a module is changed through the compliance | | `WalletOwnerChanged(address indexed wallet, address indexed previousIdentity, address indexed identity, uint256 amount)` | The ledger moves the balance of an address to the identity the registry now names | | `PositionUnresolved(bytes32 indexed wallet, uint256 amount)` | One side of a movement resolves to no identity. The amount is added to the gap on the receiving side, subtracted on the sending side | | `PositionUnderflow(address indexed identity, uint256 missing)` | A debit exceeds the position: the position goes to zero and `missing` is subtracted from the gap | | `PositionFixed(address indexed from, address indexed to, uint256 amount)` | `fixPosition` | The events of validations are listed in [Transfer validation](/reference/token-suite/transfer-validation.md). --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. 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