struct MyArgs : MixEvalArgs, MixCommonArgs
        {
            Path releaseExpr;
            MyArgs() : MixCommonArgs("hydra-eval-jobs")
            {
                mkFlag()
                    .longName("help")
                    .description("show usage information")
                    .handler([&]() {
                        printHelp(programName, std::cout);
                        throw Exit();
                    });
                mkFlag()
                    .longName("gc-roots-dir")
                    .description("garbage collector roots directory")
                    .labels({"path"})
                    .dest(&gcRootsDir);

        Path releaseExpr;

                mkFlag()
                    .longName("dry-run")
                    .description("don't create store derivations")
                    .set(&settings.readOnlyMode, true);

        struct MyArgs : LegacyArgs, MixEvalArgs
        {
            using LegacyArgs::LegacyArgs;

                expectArg("expr", &releaseExpr);
            }

        MyArgs myArgs(baseNameOf(argv[0]), [&](Strings::iterator & arg, const Strings::iterator & end) {
            if (*arg == "--gc-roots-dir")
                gcRootsDir = getArg(*arg, arg, end);
            else if (*arg == "--dry-run")
                settings.readOnlyMode = true;
            else if (*arg != "" && arg->at(0) == '-')
                return false;
            else
                releaseExpr = *arg;
            return true;
        });

        MyArgs myArgs;

        if (releaseExpr == "") throw UsageError("no expression specified");

        if (myArgs.releaseExpr == "") throw UsageError("no expression specified");

        state.evalFile(lookupFileArg(state, releaseExpr), v);

        state.evalFile(lookupFileArg(state, myArgs.releaseExpr), v);