static IResourceLoader resourceLoaderFromDir(File dir) {
  ret new IResourceLoader {
    public S loadSnippet(S snippetID) {
      ret loadTextFile(newFile(dir, psI(snippetID) + ".text"));
    }
    
    public S getTranspiled(S snippetID) {
      S src = loadTextFile(newFile(dir, psI(snippetID) + ".transpiled"));
      if (empty(src))
        print("Warning: Transpilation for " + snippetID + " not found");
      ret src;
    }
    
    public int getSnippetType(S snippetID) {
      ret parseInt(loadTextFileTrim(newFile(dir, snippetID + ".type")));
    }
    
    public S getSnippetTitle(S snippetID) {
      ret loadTextFileTrim(newFile(dir, snippetID + ".title"));
    }
    
    public File loadLibrary(S snippetID) {
      long id = psI(snippetID);
      if (isImageServerSnippet(id)) 
        ret assertIsFile(oneOfTheFilesInDir(dir, id + ".png", id + ".gif"));
      else
        ret assertIsFile(newFile(dir, id + ".bin"));
    }
  };
}

Began life as a copy of #1022668