@Override
        public Node arrayNode(ArrayNode node) {
            List<Node> result = new ArrayList<>(node.size());
            for (Node element : node.getElements()) {
                result.add(element.accept(this));
            }
            return new ArrayNode(result, node.getSourceLocation());
        }
Expands ${NAME} values inside of strings to a {@code System} property
or an environment variable.
smithy-build/src/main/java/software/amazon/smithy/build/model/SmithyBuildUtils.java