Modules

Do modules are named namespaces of values. A module can export functions, classes, constants, and other public bindings.

Importing Modules

Whole-Module Imports

Import a module by name:

import math
math.add 1 2

Module names may be dotted:

import build.tools
build.tools.compile sources

When a dotted module name is imported without renaming, the local binding is the first component. That binding is a namespace object whose nested fields mirror the rest of the dotted name.

import build.tools
import build.images

build.tools.compile sources
build.images.pack rootfs

Conceptually, import build.tools binds a local build object, then inserts the imported module at build.tools. A later import build.images extends the same local build namespace instead of replacing it.

Renaming

Use module: alias to bind the imported module directly under a different local name:

import math: m
m.add 1 2

This also works with dotted module names:

import build.tools: tools
tools.compile sources

Unlike import build.tools, this binds tools directly to the imported module. It does not create a local build namespace object.

Importing Specific Items

Import selected public items from a module:

import math:
  - add
  - subtract

add 1 2

Renaming Imported Items

Rename individual imported items:

import math:
  add: plus

plus 1 2

The left-hand side is the exported name in the module; the right-hand side is the local binding.

Combined Forms

import math:
  - add
  subtract: minus

The vertical form is useful when importing multiple modules at once:

import
  build.tools
  build.images: images
  build.deploy:
    - push
    status: deploy_status

Exporting with pub

Mark definitions as public with pub:

pub def helper x
  (x + 1)

pub let VERSION = "1.0"

# Private (not exported)
def internal_detail
  42

Only pub items are visible when a module is imported.

Module Resolution

Modules are resolved according to the host application. See the Shell Guide for details on module path configuration for dolang.