Module arena

The Arena, UniqueArena, and Handle types.

To improve translator performance and reduce memory usage, most structures are stored in an Arena. An Arena<T> stores a series of T values, indexed by Handle<T> values, which are just wrappers around integer indexes. For example, a Function’s expressions are stored in an Arena<Expression>, and compound expressions refer to their sub-expressions via Handle<Expression> values.

A UniqueArena is just like an Arena, except that it stores only a single instance of each value. The value type must implement Eq and Hash. Like an Arena, inserting a value into a UniqueArena returns a Handle which can be used to efficiently access the value, without a hash lookup. Inserting a value multiple times returns the same Handle.

If the span feature is enabled, both Arena and UniqueArena can associate a source code span with each element.

Re-exports

pub use handle::BadHandle;

pub use handle::Handle;

pub use range::BadRangeError;

pub use range::Range;

pub use unique_arena::UniqueArena;

Modules

handle 🔒

Well-typed indices into Arenas and UniqueArenas.

handle_set 🔒

The HandleSet type and associated definitions.

handlevec 🔒

The HandleVec type and associated definitions.

range 🔒

Well-typed ranges of Arenas.

unique_arena 🔒

The UniqueArena type and supporting definitions.

Structs

Arena

An arena holding some kind of component (e.g., type, constant, instruction, etc.) that can be referenced.