Standard Bridger

This patch adds a simple Legend Script for pushing ERC20 assets over the standard Optimism/Base bridge. The real bridge seems to use a mix of CCIP and CCTP bridges, as well, but this is a good starting point for understanding cross-chain actions.

src/legend-scripts/src/StandardBridger.sol

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+pragma solidity 0.8.23;
+
+import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
+
+interface StandardBridge {
+    function bridgeERC20To(
+        address _localToken,
+        address _remoteToken,
+        address _to,
+        uint256 _amount,
+        uint32 _minGasLimit,
+        bytes calldata _extraData
+    ) external;
+}
+
+contract StandardBridger {
+    StandardBridge immutable bridge;
+
+    constructor(StandardBridge bridge_) {
+        bridge = bridge_;
+    }
+
+    /**
+     *   @notice Bridge token over standard bridge.
+     */
+    function bridgeToken(address localToken,
+            address remoteToken,
+            address to,
+            uint256 amount,
+            uint32 minGasLimit,
+            bytes calldata extraData) external {
+        IERC20(localToken).approve(address(bridge), amount);
+        bridge.bridgeERC20To(localToken, remoteToken, to, amount, minGasLimit, extraData);
+    }
+}