Method eval

src/common/StateDatabase.cpp:300–344

float StateDatabase::eval(const std::string& name) {
  static StringSet evalStack;

  // avoid recursive evaluation
  if (evalStack.find(name) != evalStack.end()) {
    return getNaN();
  }

  EvalMap::const_iterator cit = evalCache.find(name);
  if (cit != evalCache.end()) {
    if (!evalStack.empty()) {
      // add this item to its dependents' sets
      ItemMap::iterator it = lookup(name);
      addDependents(it, evalStack);
    }
    return cit->second;
  }

  StringSet::iterator myStackIt = evalStack.insert(name).first;

  DEBUG_LOOKUPS(name);
  ItemMap::iterator it = items.find(name);
  if ((it == items.end()) ||
      !it->second.isSet || it->second.value.empty()) {
    evalStack.erase(myStackIt);
    return getNaN();
  }

  Expression infix;
  std::string input = it->second.value;
  input >> infix;

  Expression prefix = infixToPrefix(infix);
  const float value = evaluate(prefix);
  if (value != getNaN()) {
    evalCache[name] = value;
  }

  evalStack.erase(myStackIt);

  // add this item to its dependents' sets
  addDependents(it, evalStack);

  return value;
}


int StateDatabase::evalInt(const std::string& name) {