Struct SurfaceHub 

pub struct SurfaceHub { /* private fields */ }

The canonical multi-surface coordination point.

Holds the single canonical value per resource, the universal LensRegistry that renders and edits, an owned Cx, the registered surfaces and their SurfaceCaps, the live (surface, pane) bindings, and the append-only EditRow ledger.

Implementations

impl SurfaceHub

pub fn new() -> Self

A new hub with the universal default lens registered (writable) and no resources, surfaces, bindings, or ledger rows.

pub fn seed(&mut self, resource: Symbol, value: Expr)

Set (or replace) the canonical value of resource.

pub fn register_surface(&mut self, surface: Symbol, caps: SurfaceCaps)

Register a surface (identified by surface) with its capabilities. Re-registering replaces the stored caps.

pub fn register_surface_with_role( &mut self, surface: Symbol, caps: SurfaceCaps, role: SurfaceRole, )

Register a surface with an explicit role inside the hub.

pub fn surface_role(&self, surface: &Symbol) -> Option<SurfaceRole>

Returns the role recorded for surface.

pub fn open( &mut self, surface: &Symbol, pane: Symbol, resource: Symbol, ) -> Result<Expr>

Bind (surface, pane) to resource, render the canonical value through the universal view (projected to the surface caps via reduce_for_caps), cache that Scene for the pane, and return it.

An existing binding for the same (surface, pane) is replaced. Fails if the surface is not registered or the resource has no canonical value.

pub fn submit( &mut self, surface: &Symbol, pane: &Symbol, intent: &Expr, ) -> Result<Vec<Broadcast>>

Submit an Intent against the resource shown in (surface, pane).

The Intent is proposed and committed through the universal editor against the CURRENT canonical value; the resulting set-value operation is applied to the canonical store and appended to the ledger (attributed to the Intent origin’s operator and tick). Then, for EVERY (surface, pane) viewing that resource – including other surfaces – the new value is re-rendered, diffed against the pane’s cached Scene, the cache updated, and a Broadcast emitted. Returns all broadcasts.

Fails closed (returns an error, never panics) if the pane is not open, the resource is missing, the Intent is invalid, or the draft is not committable.

pub fn commit_value_from( &mut self, surface: &Symbol, pane: &Symbol, intent: &Expr, new_value: Expr, ) -> Result<Vec<Broadcast>>

Commit an already decoded value update from surface/pane.

Device coordinators use this when a physical Intent has already been reduced to a canonical value update. The hub still validates the Intent, enforces the source surface input capability, records exactly one append-only ledger row, and broadcasts through the same atomic path as Self::submit.

pub fn detach_surface(&mut self, surface: &Symbol) -> Vec<SurfaceBinding>

Detach a surface from this hub without changing canonical resources or ledger history.

pub fn bindings_for_resource(&self, resource: &Symbol) -> Vec<SurfaceBinding>

Returns live bindings currently showing resource.

pub fn handoff( &mut self, from: &Symbol, to: &Symbol, resource: Symbol, pane: Symbol, ) -> Result<Expr>

Hand resource off from from to to: open it on to in a new pane and return its Scene. The from surface keeps its binding, so the resource is now open on both and subsequent edits broadcast to both.

Fails if from does not currently hold resource.

pub fn ledger(&self) -> &[EditRow]

The append-only edit ledger, in submit order.

pub fn canonical(&self, resource: &Symbol) -> Option<&Expr>

The current canonical value of resource, if any.

Trait Implementations

impl Default for SurfaceHub

fn default() -> Self

Returns the “default value” for a type.