Struct BufferLocals 

pub struct BufferLocals { /* private fields */ }

Typed-map of buffer-local mode-internal state.

Stored on per-buffer host state, one map per buffer. The host writes entries (seeding at buffer construction, or on a mode’s behalf — e.g. ModeActivator::set_buffer_scope_dir); anyone reads via Self::get. Removal is pub(crate) and not yet wired to any caller.

Implementations

impl BufferLocals

pub fn new() -> Self

An empty map.

pub fn len(&self) -> usize

Number of locals stored.

pub fn is_empty(&self) -> bool

True when no local is stored.

pub fn insert<T: BufferLocal>(&mut self, value: T)

Insert (or replace) the local of type T. Public so the App can seed locals at buffer-construction time (e.g. help-mode parsing the markdown links into HelpLinks when a help buffer is constructed – the “owner” semantically is help-mode, but the App is the caller because parsing lives in the constructor).

The owner-mode check is intentionally NOT enforced here; the design gives that job to a checked ModeContext::set_local for active modes’ runtime writes, which does not exist yet. App-level construction-time seeding is a separate path: the App is presumed to insert locals owned by the buffer’s eventual major mode, and the local’s OWNER_MODE field is metadata for :describe-buffer attribution rather than an access-control mechanism on this surface. Mirrors emacs’s setq-local – any code can set a buffer-local; the major mode’s claim of ownership is by convention.

pub fn get<T: BufferLocal>(&self) -> Option<&T>

Read the local of type T if present.

pub fn iter_descriptors(&self) -> impl Iterator<Item = LocalDescriptor> + '_

Iterate over descriptors for inspection. Walks every local with its display metadata + a single-line summary. Used by :describe-buffer to enumerate all state on a buffer grouped by owner mode.

pub fn contains<T: BufferLocal>(&self) -> bool

True if a local of type T is currently stored.

Trait Implementations

impl Clone for BufferLocals

fn clone(&self) -> Self

Slice 3c.final.B.9: walks the typed-map and clone_box’s each entry so the whole BufferLocals can be deep-cloned for BufferLocalsRenderState publishes.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BufferLocals

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for BufferLocals

fn default() -> BufferLocals

Returns the “default value” for a type.