Struct Ctx 

pub struct Ctx { /* private fields */ }

The thin evaluation context threaded through the tree-walker: the unique-id source (closure identities) and the builtin module cache. It carries no module registry and no loader — a module’s imports are resolved before evaluation begins (see crate::load_module), and a loaded module is an ordinary Rc-held value, kept alive only by whatever holds it.

Implementations

impl Ctx

pub fn new() -> Self

A context with a fresh id source. Used by eval and apply.

pub fn with_ids(ids: u64) -> Self

A context resuming an id source at ids, so identities it mints continue where an earlier context left off.

A host that builds a fresh Ctx per call and hands values out between them — the Python bindings do exactly this — needs it: a module reserves its item id block when it is instantiated (see instantiate), and the programs that later use it mint closure ids from a different context. If both started at zero, an item and an unrelated closure would get the same id and __eq would call them equal. The host reads ids_used back when the context is done and seeds the next one with it.

The counter is carried by value rather than shared behind an Rc: the pointer chase it would add to every closure mint costs ~2% on fib_naive, and only the host needs the continuity.

pub fn ids_used(&self) -> u64

How far this context’s id source has run — the value to seed a successor with (see with_ids).

Trait Implementations

impl Default for Ctx

fn default() -> Self

Returns the “default value” for a type.