Worksheet

The Worksheet modality arranges components on a grid and compiles them into a linear sequence of worksheet elements. It implements all three core traits — Reducer, Component, and Modality — on a single struct.

Type Summary

Associated Type	Concrete Type
`Synced`	`WorksheetSynced`
`Ephemeral`	`WorksheetEphemeral`
`Position`	`GridPosition`
`ChildComponent`	`dyn WorksheetComponent`
`Component::Metadata`	`WorksheetMetadata`
`Component::Output`	`Vec<WorksheetElement>`
`Snapshot`	`WorksheetSnapshot`

Session type: Session<Worksheet, SessionIntent<WorksheetIntent>>

Struct

pub struct Worksheet {
    state: State<WorksheetSynced, WorksheetEphemeral>,
}

Position

GridPosition describes where a component sits on the worksheet grid:

pub struct GridPosition {
    pub row: u32,
    pub col: u32,
    // grid span, etc.
}

Implements Clone, PartialEq, Hash, Describe. Describe output: "row 2, col 3".

Synced State

pub struct WorksheetSynced {
    pub placements: Vec<ComponentPlacement<GridPosition>>,
    // resource metadata (HasResourceMeta)
}

Each placement has a component_key (e.g. "question", "section_heading") and optional component_id for customized instances.

Elements

The compiled output is a sequence of WorksheetElement values (renamed from WorksheetNode):

pub enum WorksheetElement {
    Question(QuestionElement),
    SectionHeading(SectionHeadingElement),
    // ... additional variants
}

Compilation and Grid Math

The worksheet keeps its own compile context for grid layout math. WorksheetMetadata captures the grid parameters used as the modality-level Component::Metadata:

pub struct WorksheetMetadata {
    pub cell_width: f64,
    pub cell_height: f64,
    pub margin: f64,
    // grid dimensions, node bounds, etc.
}

WorksheetMetadata: Hash enables the incremental compilation cache on Session. When the grid parameters change, the entire worksheet recompiles; when only a single placement changes, only that component recompiles.

The layout() default iterates placements, resolves bindings, and delegates to compile_child. assemble() collects the per-component WorksheetElement outputs into Vec<WorksheetElement>.

fn compile_child(
    &self,
    placement: &ComponentPlacement<GridPosition>,
    _meta: &(),
    values: &HashMap<String, PropertyValue>,
) -> Result<WorksheetElement, CompileError> {
    let component = resolve_component(&placement.component_key);
    component.compile(&(), values)
}

Intents — all WorksheetIntent variants
Components — the WorksheetComponent subtrait and built-ins
Reducer — state management via the Genvoy pattern
Command — the universal envelope wrapping WorksheetIntent
FRB Patterns — how worksheet types cross the Dart/Rust boundary