Module event 

Host-neutral event object, binding registry, and propagation driver (phase 4): n.on(type, handler) / off(), the current-event cell, and the capture -> target -> bubble dispatch. Host-neutral event object, binding registry, and propagation driver for the dynamic DOM API (phase 4).

n.on("click", handler) binds a handler to a node for an event type and returns an off token; off() unbinds. Bindings live in a process-global registry keyed by token so the generic dispatcher (and the C-ABI, which has no script host) share one source of truth. The handler itself is either a closure held by the active crate::ScriptHost (keyed by the same token) or a native Rust callback (the C-ABI / SDK path).

During dispatch the driver publishes the event into a process-global current-event cell; a handler reads target / position / key / modifiers / button / delta / value from it and mutates its prevent_default / stop_propagation / stop_immediate_propagation flags through the free functions here. A host may wrap those in a registered Event handle or call them procedurally, as the C-ABI does.

Propagation follows the DOM contract: capture from the root down to the target, dispatch at the target, then bubble back up (for events that bubble). stop_propagation halts movement to the next node after the current node’s handlers finish; stop_immediate_propagation also halts the remaining handlers on the current node.

Structs

EventBinding

One n.on(type, handler) binding.

EventData

The full event payload delivered to a handler. Positional / key / button / delta / value fields carry meaning only for the event types that produce them (a keydown has key + modifiers, a wheel has delta, an input / change has value, and so on); unused fields stay at their defaults.

Enums

EventHandler

How a bound handler is invoked at dispatch time.

Functions

clear_all_bindings

Drop all bindings (mainly for test isolation).

clear_host_bindings

Drop every host-closure binding. Called on host reset, and on hot reload before the script re-runs and re-binds.

clear_prevented_clicks

Reset the per-tick prevented-click set. The dispatcher calls this before processing a tick’s events.

current_event

Read the current event (cheap clone).

dispatch

Drive a full capture -> target -> bubble dispatch for data.

event_bubbles

Whether event_type bubbles (fires bubble-phase handlers on ancestors after the target). Mirrors the DOM: focus / blur, pointer enter / leave, and scroll do not bubble; everything else does.

event_button

ev.button().

event_current_target

ev.current_target().

event_delta

ev.delta() as (x, y).

event_key

ev.key().

event_modifiers

ev.modifiers() as (shift, ctrl, alt, super).

event_position_client

Client position (x, y) (window coordinates).

event_position_local

Local position (x, y) (relative to the target).

event_prevent_default

ev.prevent_default().

event_stop_immediate_propagation

ev.stop_immediate_propagation(). Implies stop_propagation.

event_stop_propagation

ev.stop_propagation().

event_target

ev.target().

event_type

ev.type().

event_value

ev.value().

has_bindings_for

Whether any binding exists for event_type (fast dispatch gate).

is_click_default_prevented

Whether a click on target (packed handle) was default-prevented this tick. The anchor-navigation executor consults this to honor prevent_default.

mark_prevented_click

Record that a click on target (packed handle) had its default action cancelled via prevent_default.

mint_event_token

Mint a fresh, process-unique bind / off token (always >= 1).

register_host_binding

Register a host-closure binding (token, node, type, capture). The host holds the closure itself keyed by token.

register_native_binding

Register a native-callback binding (the C-ABI / SDK path). Returns the token for the caller to hand back as the off token.

restore_host_bindings

Carry prior bindings forward past a hot reload, and report the tokens that were dropped instead.

set_current_event

Publish data as the current event before invoking handlers.

set_current_target

Update the current event’s current_target as the driver moves along the propagation path.

take_host_bindings

Remove every host-closure binding and return it, in registration order.

unregister_binding

Remove the binding for token, returning it when present.