Namespaces

namespace NameSpaceName {
    // ...
}

Everything between the braces in this statement is in the namespace NameSpaceName and must be referenced as such. Any code outside this namespace must either use qualified names for anything within the name of the namespace, or be in a file with an appropriate using declaration in order to import this namespace:

using NameSpaceName;

// ...

For example, if the namespace Gtk is imported with using Gtk; you can simply write Window instead of Gtk.Window. A fully qualified name would only be necessary in case of ambiguity, for example between GLib.Object and Gtk.Object.

The namespace GLib is imported by default. Imagine an invisible using GLib; line at the beginning of every Vala file.

Everything that you don't put into a separate namespace will land in the anonymous global namespace. If you have to reference the global namespace explicitly due to ambiguity you can do that with the global:: prefix.

Namespaces can be nested, either by nesting one declaration inside another, or by giving a name of the form NameSpace1.NameSpace2.

Several other types of definition can declare themselves to be inside a namespace by following the same naming convention, e.g.

class NameSpace1.Test { ... }. Note that when doing this, the final namespace of the definition will be the one the declaration is nested in plus the namespaces declared in the definition.