static IResourceLoader resourceLoaderFromDirWithInitializing(File dir) {
  ret new IResourceLoader {
    public S loadSnippet(S snippetID) ctex {
      long id = psI(snippetID);
      File f = newFile(dir, id + ".text");
      S text = loadTextFile(f);
      if (text != null) ret text;
      saveTextFile(f, text = loadSnippet_noResourceLoader(id, false));
      ret text;
    }
    
    public S getTranspiled(S snippetID) {
      long id = psI(snippetID);
      File f = newFile(dir, id + ".transpiled");
      if (fileExists(f))
        ret loadTextFile(f);
      S src = getServerTranspiled2_noResourceLoader(snippetID);
      saveTextFile(f, src);
      ret src;
    }
    
    public int getSnippetType(S snippetID) {
      long id = psI(snippetID);
      File f = newFile(dir, id + ".type");
      if (fileExists(f))
        ret parseInt(loadTextFileTrim(f));
      int type = getSnippetType_noResourceLoader(id);
      saveTextFile(f, str(type));
      ret type;
    }
    
    public S getSnippetTitle(S snippetID) {
      long id = psI(snippetID);
      File f = newFile(dir, id + ".title");
      if (fileExists(f))
        ret loadTextFileTrim(f);
      S title = getSnippetTitle_noResourceLoader(snippetID);
      saveTextFile(f, title);
      ret title;
    }
    
    public File loadLibrary(S snippetID) {
      long id = psI(snippetID);
      File f = newFile(dir, isImageServerSnippet(id) ? id + ".png" : id + ".bin");
      if (fileExists(f))
        ret f;
      copyFile(loadBinarySnippet_noResourceLoader(snippetID), f);
      ret f;
    }
  };
}

Began life as a copy of #1029946