Namespaces

Namespaces are only relevant during compilation in order to keep track of all declared objects available in the current scope.

There are three distinct namespaces:

Type Namespace

• Component definitions

• enum/struct types

Element Namespace

• Component instances

• Parameters

Property Namespace

• Contains builtin and user-defined properties

Each has slightly different lookup rules:

Type

• Resolved by searching local scope, and traversing up until a match is found.

Element

• Resolve in local scope only.

• Only exception is a ‘signal’ instance that effectively uses ‘type’ namespace search rules.

Property

• Global namespace

• User-defined properties can only be added in the root namespace.

Implementation

A single namespace registry class exists throughout compilation that manages namespaces. This single instance is carried through the compiler everywhere.

As objects are defined/instantiated, they are registered with the namespace using the following methods:

• .register_element(name, ref)

• .register_type(name, ref)

• .register_property(name, ref)

At any point, the compiler can query the namespace:

• .lookup_element(name)

• .lookup_type(name)

• .lookup_property(name)

The above return None if not found.

Changing scope when entering/exiting a component definition:

.enter_scope()

pushes a blank scope onto the type-stack and element-stack

.exit_scope()

pop and discard top of type-stack and element-stack

Hierarchical references are handled elsewhere. Component instances are traversed manually.