vertfn — Go linter for Vertical Function Ordering

Disclaimer: false positives; practically this is useful for "exploration" rather than for "enforcement"

Vertical Ordering
In general we want function call dependencies to point in the downward direction. That is, a function that is called should be bellow a function that does the calling. This creates a nice flow down the source code module from the high level to low level. As in newspaper articles, we expect the most important concepts to come first, and we expect them to be expressed with the least amount of polluting detail. We expect the low-level details to come last. This allows us to skim source files, getting the gist from the frist few functions, without having to immerge ourselves in the details.
— Clean Code, Chapter 5, p84, Robert C. Martin, 2009

go install github.com/nikolaydubina/vertfn@latest

verfn --verbose ./...

False Positives

Improving false positive rate is good, such as for following cases:

• same function names but different classes
• same function names but from different packages
• functions passed as arguments
• functions passed as arguments and argument name matches existing function names

Appendix A: Canonical Java Example

Clean Code, Chapter 5, code example WikiPageResponder.java

code

public class WikiPageResponder implements SecureResponder {
  protected WikiPage page;
  protected PageData pageData;
  protected String pageTitle;
  protected Request request;
  protected PageCrawler crawler;

  public Response makeResponse(FitNesseContext context, Request request)
    throws Exception {
    String pageName = getPageNameOrDefault(request, "FrontPage");
    loadPage(pageName, context);
    if (page == null)
      return notFoundResponse(context, request);
    else
      return makePageResponse(context);
  }

  private String getPageNameOrDefault(Request request, String defaultPageName)
  {
    String pageName = request.getResource();
    if (StringUtil.isBlank(pageName))
      pageName = defaultPageName;

    return pageName;
  }

  protected void loadPage(String resource, FitNesseContext context)
    throws Exception {
    WikiPagePath path = PathParser.parse(resource);
    crawler = context.root.getPageCrawler();
    crawler.setDeadEndStrategy(new VirtualEnabledPageCrawler());
    page = crawler.getPage(context.root, path);
    if (page != null)
      pageData = page.getData();
  }

  private Response notFoundResponse(FitNesseContext context, Request request)
    throws Exception {
    return new NotFoundResponder().makeResponse(context, request);
  }

  private SimpleResponse makePageResponse(FitNesseContext context)
    throws Exception {
    pageTitle = PathParser.render(crawler.getFullPath(page));
    String html = makeHtml(context);

    SimpleResponse response = new SimpleResponse();
    response.setMaxAge(0);
    response.setContent(html);
    return response;
  }
  
  ...
}