Bare Cartons

A file that never calls export is a Bare Carton. Importing it returns a Carton::Namespace of the constants and top-level methods, called Helpers, that the file defines, as if it had exported them all.

Its Box stays private, so an importer cannot eval or require inside it. Bare Cartons suit existing code you want to load in a Box without changing it; new Cartons should export deliberately.

# main.rb: some_script.rb never calls export
Toolbox = import 'some_script'

Toolbox::SomeConstant
Toolbox.helper
Toolbox[:helper]         # => #<Method: ...helper()>, not called
Toolbox.fetch(:SomeConstant)
Toolbox => { helper:, **rest }
Toolbox                  # => #<Carton::Namespace helper, SomeConstant>

• Only constants and Helpers the Entrypoint introduces count, not constants the runtime already defined.
• Constants are read when the import finishes, so an autoloaded top-level constant loads then rather than on first use.
• Lookups by name, such as [], fetch, and destructuring, return a Helper’s Method object, so they never call it.
• A Helper named like a Carton::Namespace method, such as fetch, keys, or name, raises Carton::ExportError instead of hiding it.