Struct SlotData 

pub struct SlotData { /* private fields */ }

Dense Vec indexed by slot_id — the bridge between Rust page handlers and the IR walker.

Handlers create a SlotData, populate it with values (title, user name, nav items, etc.), then the walker reads slot values when it encounters DYN_TEXT, DYN_ATTR, SHOW_IF, LIST opcodes.

Implementations

impl SlotData

pub fn new(capacity: usize) -> Self

Create a new SlotData with capacity Null-initialized slots.

This is the only constructor that can be undersized relative to a module’s slot table. Prefer SlotData::new_from_defaults or SlotData::from_json, which size themselves from the module; new is for tests and for callers that know their own slot count.

pub fn set(&mut self, slot_id: u16, value: SlotValue)

Set a slot value, growing the backing storage if slot_id is past the end (new entries are Null).

This used to be a silent no-op when out of bounds, which made a LIST whose item_slot_id exceeded the SlotData length render every row identically with no error at all. Growing is cheap, and a write outside the module’s declared slot table cannot reach here from a parsed module — IrModule::validate rejects an opcode naming an undeclared slot at parse time — so the branch only catches a caller that sized its own SlotData too small, and warns under the tracing feature.

Verified by: crates/forma-ir/src/slot.rs > “set_grows_instead_of_silently_dropping” Verified by: crates/forma-ir/src/parser.rs > “validate_rejects_list_item_slot_not_in_table”

pub fn replace(&mut self, slot_id: u16, value: SlotValue) -> SlotValue

Set a slot value and return the previous one.

This is the primitive the walker’s LIST loop is built on: it binds the row’s item (and any PROP the body extracts from it) by swapping values in, then swaps the saved originals back when the row ends. That keeps per-row scoping without the deep SlotData clone the loop used to take, which made a list cost O(rows x slots) instead of O(rows).

Verified by: crates/forma-ir/tests/list_scaling.rs > “list_walk_allocations_are_linear_in_row_count”

pub fn get(&self, slot_id: u16) -> &SlotValue

Get a reference to a slot value. Returns &Null if out of bounds.

pub fn get_text(&self, slot_id: u16) -> Option<&str>

Get the text content of a slot. Returns Some(&str) if Text, None otherwise.

pub fn from_json(json_str: &str, module: &IrModule) -> Result<Self, IrError>

Create SlotData from a named-key JSON string, resolving names to slot IDs via the module’s string table and slot table.

The JSON must be an object (e.g., {"title": "Hello", "count": 42}). Each key is resolved against the slot table: the slot entry’s name_str_idx is looked up in the string table to find the slot name. If it matches a JSON key, the JSON value is converted to a SlotValue and stored at that slot_id.

Unknown JSON keys (not in the slot table) are silently ignored. Starts from slot table defaults so missing keys retain their defaults. JSON numbers become IEEE-754 f64 values. Decimal spellings use correctly rounded parsing, so finite f64 values serialized to JSON preserve their bits, including negative zero. This does not make all integers above 2^53 exact. Island state serialization subsequently canonicalizes negative zero to zero under the Serialize9 contract.

pub fn new_from_defaults(table: &SlotTable) -> Self

Create SlotData pre-populated from the IR slot table defaults. Server-sourced slots with no default -> Null. Client-sourced slots with defaults -> parsed from default_bytes.

Trait Implementations

impl Clone for SlotData

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SlotData

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

Formats the value using the given formatter.