Method ParseFunction

contrib/libs/flatbuffers/src/idl_parser.cpp:2023–2064

}

CheckedError Parser::ParseFunction(const std::string *name, Value &e) {
  ParseDepthGuard depth_guard(this);
  ECHECK(depth_guard.Check());

  // Copy name, attribute will be changed on NEXT().
  const auto functionname = attribute_;
  if (!IsFloat(e.type.base_type)) {
    return Error(functionname + ": type of argument mismatch, expecting: " +
                 TypeName(BASE_TYPE_DOUBLE) +
                 ", found: " + TypeName(e.type.base_type) +
                 ", name: " + (name ? *name : "") + ", value: " + e.constant);
  }
  NEXT();
  EXPECT('(');
  ECHECK(ParseSingleValue(name, e, false));
  EXPECT(')');
  // calculate with double precision
  double x, y = 0.0;
  ECHECK(atot(e.constant.c_str(), *this, &x));
  // clang-format off
  auto func_match = false;
  #define FLATBUFFERS_FN_DOUBLE(name, op) \
    if (!func_match && functionname == name) { y = op; func_match = true; }
  FLATBUFFERS_FN_DOUBLE("deg", x / kPi * 180);
  FLATBUFFERS_FN_DOUBLE("rad", x * kPi / 180);
  FLATBUFFERS_FN_DOUBLE("sin", sin(x));
  FLATBUFFERS_FN_DOUBLE("cos", cos(x));
  FLATBUFFERS_FN_DOUBLE("tan", tan(x));
  FLATBUFFERS_FN_DOUBLE("asin", asin(x));
  FLATBUFFERS_FN_DOUBLE("acos", acos(x));
  FLATBUFFERS_FN_DOUBLE("atan", atan(x));
  // TODO(wvo): add more useful conversion functions here.
  #undef FLATBUFFERS_FN_DOUBLE
  // clang-format on
  if (true != func_match) {
    return Error(std::string("Unknown conversion function: ") + functionname +
                 ", field name: " + (name ? *name : "") +
                 ", value: " + e.constant);
  }
  e.constant = NumToString(y);
  return NoError();
}

CheckedError Parser::TryTypedValue(const std::string *name, int dtoken,
                                   bool check, Value &e, BaseType req,