ava/namespaces.md

Namespaces

Namespaces are the primary organizational unit of Ava. Every Ava file must define a namespace. The namespace is ALWAYS the first line of the file.

Syntax

Each namespace is an ordered, delimited, list of names. Each name is separated by the . character.

<name>[.<name>]*

• At least one name MUST be specified.
• CANNOT contain more than one . character in a row.
• CANNOT begin with . character.
• CANNOT end with . character.
• CANNOT use a Reserved Name.

Examples

• foo
• foo.bar.baz
• language.v0
• collections.v0

Reserved Names

Any namespaces provided with a particular Ava distribution are considered reserved. This means that, for example, the following namespaces cannot be used:

• language
• collections

Language Namespace

The language namespace is automatically imported into every Ava file.

Exports

Each namespace MAY export defintions using the export keyword. If some definition is exported, it may be imported into another namespace. Definitions are NOT exported by default -- it is an opt-in process. As noted in the Definitions documentation, the export keyword may be used at the beginning of any definition.

Imports

Imports immediately follow the namespace definition in each file. Each file may have zero or more imports. Imports bring definitions from another namespace into scope.

Syntax

Each import is a single, fully-qualified name. Imported names MAY be mapped to some alternative name. An import may refer to a specific namespace or it may refer to some specific definition within a namespace.

TODO: Account for type classes. How can we easily import instances? One option is to NOT do this. Ever. Just resolve EVERY possible instance during compilation and make them available within the scope of the program. Global. Very strict one-instance-per-thing side-effect, but could be useful.

import <namespace>[.<definition name>] [as <name>]

Examples

import collections.NonEmptyList as NEL
import collections.Queue
import collections