Function materializeLazyBuiltin

packages/lang-core/src/parser/materialize.ts:80–97

* If node is a lazy builtin like Each(arr, varName, template), temporarily * scope the iterator variable during materialization so template refs resolve. * Returns the materialized Comp node, or null if not a lazy builtin.

(
  node: ASTNode & { k: "Comp" },
  ctx: MaterializeCtx,
  scopedRefs: ReadonlySet<string>,
)

 * Returns the materialized Comp node, or null if not a lazy builtin.
 */
function materializeLazyBuiltin(
  node: ASTNode & { k: "Comp" },
  ctx: MaterializeCtx,
  scopedRefs: ReadonlySet<string>,
): ASTNode | null {
  if (!LAZY_BUILTINS.has(node.name) || node.args.length < 3) return null;
  const varArg = node.args[1];
  const varName = varArg.k === "Ref" ? varArg.n : varArg.k === "Str" ? varArg.v : null;
  if (!varName) return null;

  const nextScopedRefs = new Set(scopedRefs);
  nextScopedRefs.add(varName);
  // Skip args[1] (the iterator declaration) but preserve scoped refs elsewhere.
  const recursedArgs = node.args.map((a, i) =>
    i === 1 ? a : materializeExprInternal(a, ctx, nextScopedRefs),
  );
  return { ...node, args: recursedArgs };
}

function materializeExprInternal(
  node: ASTNode,