1  // SPDX-License-Identifier: UNLICENSED
 2  pragma solidity >=0.8.17 <=0.9.0;
 3  
 4  import { Script } from "forge-std/Script.sol";
 5  
 6  abstract contract BaseScript is Script {
 7      /// @dev Included to enable compilation of the script without a $MNEMONIC environment variable.
 8      string internal constant TEST_MNEMONIC = "test test test test test test test test test test test junk";
 9  
10      /// @dev The address of the transaction broadcaster.
11      address internal broadcaster;
12  
13      /// @dev Used to derive the broadcaster's address if $ETH_FROM is not defined.
14      string internal mnemonic;
15  
16      /// @dev Initializes the transaction broadcaster like this:
17      ///
18      /// - If $ETH_FROM is defined, use it.
19      /// - Otherwise, derive the broadcaster address from $MNEMONIC.
20      /// - If $MNEMONIC is not defined, default to a test mnemonic.
21      ///
22      /// The use case for $ETH_FROM is to specify the broadcaster key and its address via the command line.
23      constructor() {
24          address from = vm.envOr({ name: "ETH_FROM", defaultValue: address(0) });
25          if (from != address(0)) {
26              broadcaster = from;
27          } else {
28              mnemonic = vm.envOr({ name: "MNEMONIC", defaultValue: TEST_MNEMONIC });
29              (broadcaster,) = deriveRememberKey({ mnemonic: mnemonic, index: 0 });
30          }
31      }
32  
33      modifier broadcast() {
34          vm.startBroadcast(broadcaster);
35          _;
36          vm.stopBroadcast();
37      }
38  }