int ret = 0;

QApplication a(argc, argv);

// Either read a config file specified as an input argument or try to read

// a file "config.hjson" in the application directory.

std::string configPath = argc > 1 ? argv[1] :

QCoreApplication::applicationDirPath().toStdString() + "/config.hjson";

// The root node for our config tree (will have type Undefined here).

Hjson::Value config;

try {

Hjson::DecoderOptions opt;

// Throws a helpful error if the user has accidentally given a value for

// the same config key twice or more.

opt.duplicateKeyException = true;

// Makes sure that empty lines and custom indentation are kept when the

// config file is rewritten.

opt.whitespaceAsComments = true;

config = Hjson::UnmarshalFromFile(configPath, opt);

} catch(const Hjson::syntax_error& e) {

std::fprintf(stderr, "Error in config: %s\n\n\n", e.what());

std::fprintf(stdout, "Default config:\n\n");

std::fprintf(stdout, "%s", _szDefaultConfig);

return 1;

} catch(const Hjson::file_error&) {

}

// We have a base of default config values in the string _szDefaultConfig,

// but all of them (and relevant comments) can be replaced here by what has

// been read from the config file.

config = Hjson::Merge(Hjson::Unmarshal(_szDefaultConfig), config);

try {

// Add working directory to possible locations for the "platforms" directory.

QCoreApplication::addLibraryPath(".");

MainWidget w(config);

// Throws Hjson::type_mismatch if the config values are not of type Int64

// or Double. The mismatch can instead be silently ignored by calling

// to_int64(), for example config[Cfg::mainWindowWidth].to_int64(). Then

// the value 0 is used if no conversion could be performed, and no error is

// thrown.

w.resize(config[Cfg::mainWindowWidth], config[Cfg::mainWindowHeight]);

w.show();

// The exec() function call does not return until the UI has been closed by the user.

ret = a.exec();

config[Cfg::mainWindowWidth] = w.width();

config[Cfg::mainWindowHeight] = w.height();

} catch(const Hjson::type_mismatch& e) {

std::fprintf(stderr, "Type mismatch in config file: %s\n", e.what());

return 1;

}

try {

Hjson::EncoderOptions opt;

// Just because it looks nice.

opt.omitRootBraces = true;

// Rewrites the same config file that was previously read as input. Or

// creates a new config file if none existed.

Hjson::MarshalToFile(config, configPath, opt);

} catch(const std::exception& e) {

std::fprintf(stderr, "Failed to write config file '%s': %s\n", configPath.c_str(), e.what());

return 1;

}

return ret;