Function evaluate

packages/lang-core/src/runtime/evaluator.ts:42–238

(
  node: ASTNode,
  context: EvaluationContext,
  schemaCtx?: SchemaContext,
)

 * Evaluate an AST node to a runtime value.
 */
export function evaluate(
  node: ASTNode,
  context: EvaluationContext,
  schemaCtx?: SchemaContext,
): unknown {
  switch (node.k) {
    // ── Literals ──────────────────────────────────────────────────────────
    case "Str":
      return node.v;
    case "Num":
      return node.v;
    case "Bool":
      return node.v;
    case "Null":
      return null;
    case "Ph":
      return null;

    // ── State references ──────────────────────────────────────────────────
    case "StateRef":
      return context.extraScope?.[node.n] ?? context.getState(node.n);

    // ── References ────────────────────────────────────────────────────────
    case "Ref":
    case "RuntimeRef":
      return context.resolveRef(node.n);

    // ── Collections ───────────────────────────────────────────────────────
    case "Arr":
      return node.els.map((el) => evaluate(el, context));
    case "Obj":
      return Object.fromEntries(node.entries.map(([k, v]) => [k, evaluate(v, context)]));

    // ── Component ─────────────────────────────────────────────────────────
    case "Comp": {
      // Lazy builtins — control their own evaluation
      if (LAZY_BUILTINS.has(node.name)) {
        return evaluateLazyBuiltin(node.name, node.args, context, schemaCtx);
      }
      // Check shared builtin registry first
      const builtin = BUILTINS[node.name];
      if (builtin) {
        const args = node.args.map((a) => evaluate(a, context));
        return builtin.fn(...args);
      }
      // Action calls → evaluate to ActionPlan/ActionStep
      if (ACTION_NAMES.has(node.name)) {
        return evaluateActionCall(node.name, node.args, context);
      }
      // If parser already mapped args→props (via materializeExpr), use named props.
      // With schema context: emit ReactiveAssign for StateRef on reactive props.
      // Without schema context: preserve StateRef as AST for evaluate-tree to handle.
      if (node.mappedProps) {
        const def = schemaCtx?.library.components[node.name];
        const props: Record<string, unknown> = {};
        for (const [key, val] of Object.entries(node.mappedProps)) {
          const propSchema = def?.props?.shape?.[key];
          if (val.k === "StateRef" && propSchema && isReactiveSchema(propSchema)) {