sclass CodeSafetyChecker {

  // general data

  SS identifierSafetyMap;

  bool identifiersStartingWithDollarAreSafe;

  // data for code currently tested

  S code;

  Set<S> identifiers;

  LS unknownIdentifiers;

  LS tags;

  void init {

    if (identifierSafetyMap == null)

      identifierSafetyMap = codeAnalysis_identifierSafetyMap();

  }

  LS tokenize(S code) { ret javaTok(code); }

  run {

    init();

    LS tok = tokenize(code);

    tok_inStringEvals(tok); 

    identifiers = tok_allIdentifiersWithoutColonEquals(tok);

    unknownIdentifiers = new L;

    Set<S> tags = treeSet();

    for (S id : identifiers) {

      S tag;

      if (identifiersStartingWithDollarAreSafe && startsWith(id, "$"))

        tag = "safe";

      else

        tag = or2(mapGet(identifierSafetyMap, id), "?");

      if (eq(tag, "?"))

        unknownIdentifiers.add(id);

      tags.addAll(tokSplitAtComma(tag));

    }

    this.tags = simplifySafetyTags(tags);

    if (empty(this.tags)) this.tags.add("safe");

  }

  S checkCode(S code) {

    this.code = code;

    run();

    ret joinWithComma(tags);

  }

  S verbalCheckResult(S code) {

    checkCode(code);

    ret verbalCheckResult();

  }

  S verbalCheckResult() {

    S safety = joinWithComma(tags);

    if (neq(safety, "safe") && nempty(unknownIdentifiers))

      safety += ". Unknown identifiers: " + joinWithComma(unknownIdentifiers);

    ret safety;

  }

  void markSafe(S... ids) {

    init();

    putMultipleKeys(identifierSafetyMap, asList(ids), "safe");

  }

  bool isSafe() {

    ret eq(tags, ll("safe"));

  }

}