8.5 Exports: export🔗ℹ

By default, all of a module’s definitions are private to the module. The export form specifies definitions to be made available where the module is imported.

export:

export_clause

....

An export form can only appear in a module body or a namespace body. Specifying multiple export_clauses in a single export is the same as using multiple export forms each with a single export_clause.

Each identifier can be exported at most once from a module across all exports within the module. More precisely, the external name for each export must be distinct; the same internal binding can be exported multiple times under different external names.

The simplest export_clause is just an identifier that names a binding within the module. The binding can be from either a local definition or from an import.

export:

color

pi

def color = "blue"

def pi = 3.14

The export form also can be combined with a definition to export the names defined by the definition:

export def color = "blue"

export fun greet(who):

"Hello, " ++ who

When a class or namespace is exported, bindings introduced by the class or namespace—such as the constructor, accessors, predicates, and methods, or the bindings inside a namespace—are exported along with it. So, for example,

export:

Posn

class Posn(x, y)

exports Posn, Posn.x, Posn.y, and so on.

export:

rename:

hue as color

def hue = "blue"

import:

"f2c.rhm" open

export:

all_from("f2c.rhm")

The all_from form with .namespace_id re-exports everything that is exported by namespace_id, independent of the bindings that are imported or exposed from the namespace. A module import without open binds a namespace (based on the imported module’s name), so this form of all_from can be used to re-export all of the bindings of another module.

import:

"f2c.rhm"

namespace extras:

export: def

def freezing_f = 32

export:

all_from(.f2c)

all_from(.extras)

import:

"f2c.rhm" open

export:

all_from("f2c.rhm"):

except fahrenheit_freezing