scope readLocally.

static void readLocally(S progID, S varNames) {
  readLocally2(mc(), progID, varNames);
}

static void readLocally(S varNames) {
  readLocally2(mc(), programID(), varNames);
}

static void readLocally2(O obj, S varNames) {
  readLocally2(obj, programID(), varNames);
}

static int readLocally_stringLength;

static new ThreadLocal<Bool> readLocally2_allDynamic;
static new ThreadLocal readLocally2_classFinder;

sbool #useTwoThreads = true;

// read a string variable from standard storage
// does not overwrite variable contents if there is no file
static void readLocally2(O obj, S progID, S varNames) ctex {
  bool allDynamic = isTrue(getAndClearThreadLocal(readLocally2_allDynamic));
  for (S variableName : javaTokC(varNames)) {
    File textFile = new File(programDir(progID), variableName + ".text");
    
    S value = loadTextFile(textFile);
    if (value != null)
      set(main.class, variableName, value);
    else {
      File structureFile = new File(programDir(progID), variableName + ".structure");
      value = loadTextFile(structureFile);
      
      if (value == null) {
        File structureGZFile = new File(programDir(progID), variableName + ".structure.gz");
        if (!structureGZFile.isFile()) ret;
        temp new CloseablesHolder ch;
        Producer<S> tokenizer = gzFileTokenReaderForUnstruct(structureGZFile, ch);
        if (useTwoThreads) {
          tokenizer = moveProducerToNewThread(tokenizer, ch);
          ifdef readLocally_debug
            tokenizer = debugProducer(tokenizer);
          endifdef
        }
        O o = unstructure_tok(tokenizer, allDynamic, readLocally2_classFinder!);
        readLocally_set(obj, variableName, o);
        ret;
      }
      
      readLocally_stringLength = l(value);
      if (nempty(value))
        readLocally_set(obj, variableName, unstructure(value, allDynamic, readLocally2_classFinder!));
    }
  }
}

static void readLocally_set(O c, S varName, O value) {
  O oldValue = get(c, varName);
  if (oldValue instanceof List && !(oldValue instanceof ArrayList) && value != null) {
    // Assume it's a synchroList.
    value = synchroList((L) value);
  }
  set(c, varName, value);
}

end scope

Began life as a copy of #1001043