A package is a namespace to which classes may belong. Packages are introduced with the package keyword at the beginning of a file:

package org.frostlang.examples

After a package declaration, all classes appearing in the same file are considered to belong to that package.

package com.example.program

class A { }

class B { }

This example defines two classes, with fully-qualified names com.example.program.A and com.example.program.B. Classes may be referred to by relative names. For instance, from within the class com.example.program.A, the name B would be taken to refer to com.example.program.B. From within com.example.C, the name program.A would be taken to refer to com.example.program.A.


Classes can always be referenced by their fully qualified names, such as frost.core.String. Because it would be inconvenient to always have to write out the full name of a class, there is a uses declaration which allows you to refer to a class by its simple name:


class NewExample : Example {

After the uses declaration, the name Example refers to the class All of Frost's built-in classes, other than those in the frost.unsafe package, are "used" automatically and so are always available by their simple names.