## 6.3.1 Variables and Scopes

Within the scope of a tag library there are a number of pre-defined variables including:

- `actionName` - The currently executing action name
- `controllerName` - The currently executing controller name
- `flash` - The flash object
- `grailsApplication` - The GrailsApplication instance
- `out` - The response writer for writing to the output stream
- `pageScope` - A reference to the pageScope object used for GSP rendering (i.e. the binding)
- `params` - The params object for retrieving request parameters
- `pluginContextPath` - The context path to the plugin that contains the tag library
- `request` - The HttpServletRequest instance
- `response` - The HttpServletResponse instance
- `servletContext` - The javax.servlet.ServletContext instance
- `session` - The HttpSession instance