feat: add export string value

src/ScriptTools.sol

@@ -166,6 +166,31 @@ library ScriptTools {
         _doExport(name, json);
     }
 
+    /**
+     * @notice Used to export important values to higher level deploy scripts.
+     *         Note waiting on Foundry to have better primitives, but roll our own for now.
+     * @dev Requires FOUNDRY_EXPORTS_NAME to be set.
+     * @param label The label of the address.
+     * @param val The value to export.
+     */
+    function exportValue(string memory label, string memory val) internal {
+        exportValue(vm.envString("FOUNDRY_EXPORTS_NAME"), label, val);
+    }
+
+    /**
+     * @notice Used to export important values to higher level deploy scripts.
+     *         Note waiting on Foundry to have better primitives, but roll our own for now.
+     * @dev Set FOUNDRY_EXPORTS_NAME to override the name of the json file.
+     * @param name The name to give the json file.
+     * @param label The label of the address.
+     * @param val The value to export.
+     */
+    function exportValue(string memory name, string memory label, string memory val) internal {
+        name = vm.envOr("FOUNDRY_EXPORTS_NAME", name);
+        string memory json = vm.serializeString(EXPORT_JSON_KEY, label, val);
+        _doExport(name, json);
+    }
+
     /**
      * @dev Common logic to export JSON files.
      * @param name The name to give the json file

src/tests/ScriptToolsTest.t.sol

@@ -70,6 +70,15 @@ contract ScriptToolTest is DssTest {
         loadedExports = ScriptTools.readOutput("myExports", 1);
         assertEq(stdJson.readUint(loadedExports, ".label1"), 1);
         assertEq(stdJson.readUint(loadedExports, ".label2"), 2);
+
+        // Export some values and write to output
+        ScriptTools.exportValue("myExports", "str-label1", "str1");
+        ScriptTools.exportValue("myExports", "str-label2", "str2");
+
+        // Simulate a subsequent run loading a previously written file (use latest deploy)
+        loadedExports = ScriptTools.readOutput("myExports", 1);
+        assertEq(stdJson.readString(loadedExports, ".str-label1"), "str1");
+        assertEq(stdJson.readString(loadedExports, ".str-label2"), "str2");
     }
 
 }