#include <eqpalg/exp_macro/delta.h>
#include <boost/regex.hpp>
#include <sstream>
std::string replace_delta_macro(std::string&& exp_str) {
  boost::regex base_regex("delta\\((\\d+)\\)");
  std::string plv;
  std::stringstream ss;
  ss << "abs(pv$1_1-pv$1_0)";
  plv = ss.str();
  auto ret = boost::regex_replace(exp_str, base_regex, plv);
  return ret;
}