Add EIP-5773: Multi-Resource Token standard

assets/eip-5773/contracts/IMultiAsset.sol

@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: CC0-1.0
+
+pragma solidity ^0.8.0;
+
+interface IMultiAsset {
+    event AssetSet(uint64 assetId);
+
+    event AssetAddedToToken(
+        uint256 indexed tokenId,
+        uint64 indexed assetId,
+        uint64 indexed replacesId
+    );
+
+    event AssetAccepted(
+        uint256 indexed tokenId,
+        uint64 indexed assetId,
+        uint64 indexed replacesId
+    );
+
+    event AssetRejected(uint256 indexed tokenId, uint64 indexed assetId);
+
+    event AssetPrioritySet(uint256 indexed tokenId);
+
+    event ApprovalForAssets(
+        address indexed owner,
+        address indexed approved,
+        uint256 indexed tokenId
+    );
+
+    event ApprovalForAllForAssets(
+        address indexed owner,
+        address indexed operator,
+        bool approved
+    );
+
+    function acceptAsset(
+        uint256 tokenId,
+        uint256 index,
+        uint64 assetId
+    ) external;
+
+    function rejectAsset(
+        uint256 tokenId,
+        uint256 index,
+        uint64 assetId
+    ) external;
+
+    function rejectAllAssets(uint256 tokenId, uint256 maxRejections) external;
+
+    function setPriority(uint256 tokenId, uint16[] calldata priorities)
+        external;
+
+    function getActiveAssets(uint256 tokenId)
+        external
+        view
+        returns (uint64[] memory);
+
+    function getPendingAssets(uint256 tokenId)
+        external
+        view
+        returns (uint64[] memory);
+
+    function getActiveAssetPriorities(uint256 tokenId)
+        external
+        view
+        returns (uint16[] memory);
+
+    function getAssetReplacements(uint256 tokenId, uint64 newAssetId)
+        external
+        view
+        returns (uint64);
+
+    function getAssetMetadata(uint256 tokenId, uint64 assetId)
+        external
+        view
+        returns (string memory);
+
+    function approveForAssets(address to, uint256 tokenId) external;
+
+    function getApprovedForAssets(uint256 tokenId)
+        external
+        view
+        returns (address);
+
+    function setApprovalForAllForAssets(address operator, bool approved)
+        external;
+
+    function isApprovedForAllForAssets(address owner, address operator)
+        external
+        view
+        returns (bool);
+}