private function initMappings(Configuration $config)
    {
        $this->mappings = [
            'PERIDOT_GREP' => [$config, 'setGrep'],
            'PERIDOT_REPORTER' => [$config, 'setReporter'],
            'PERIDOT_PATH' => [$config, 'setPath'],
            'PERIDOT_COLORS_ENABLED' => [$this, 'handleBooleanEnv', false, [$config, 'disableColors']],
            'PERIDOT_STOP_ON_FAILURE' => [$this, 'handleBooleanEnv', true, [$config, 'stopOnFailure']],
            'PERIDOT_DSL' => [$config, 'setDsl'],
            'PERIDOT_CONFIGURATION_FILE' => [$config, 'setConfigurationFile']
        ];
    }