- [Basic System Structure](#Basic-System-Structure)
- [Directives](#directives)
- [keepalive directive](#keepalive-directive)
- [singleton directive](#singleton-directive)
- [functions](#functions)
- [restore](#restore)
- [Links](#links)
## Basic System Structure
A Vogue system is a database of interlinked instances and their persistent data. Two things are required to start: A group (usually a directory) of vogue modules that a system knows, and a database to load from or create (usually in the form of a single file).
At the initial creation of a Vogue system, if there is no database to load from, any template module with the [singleton directive](#singleton-directive) will have an instance created of itself, without any predefined parameters.
When a database is loaded, all instances who's template module has the [keepalive directive](#keepalive-directive) will be [restored](#restore).
## Keepalive Directive
The keepalive directive is used to describe that a module should always remain in memory. This directive applies only to instances. This means that if no instances exist of a particular template module with the keepalive directive, then no instances will be restored.
```vogue
keepalive;
```
## Singleton Directive
The singleton directive is used to describe a template module which should always have an instance of itself in memory. If one does not exist, it will be created. A system will never be running in a state where a template module which has a singleton directive does not have a corresponding instance.
The singleton directive implies the keepalive directive.
```vogue
singleton;
```
## Functions
functions can be referred to in other functions with or without the `this.` prefix. Use the prefix to disambiguate if local variables exist with the same identifier.
