3

我想使用 std::wstring 类型编写 ChaiScript 代码，如下面的 c++ 代码。

#include <iostream>

int testfunc(std::wstring s, std::wstring t)
{
    if(s==t)
    {
        std::cout << "1" << std::endl;
    }

    if(s[1]==t[1])
    {
        std::cout << "2" << std::endl;
    }

    if(s==L"aaaa")
    {
        std::cout << "3" << std::endl;
    }

    if(s[1]==L'b')
    {
        std::cout << "4" << std::endl;
    }

    return 5;
}

int main()
{
    std::cout << testfunc(std::wstring(L"abcd"), std::wstring(L"abbb"));

    return 0;
}

D:\TestWork\test_chaiscript>t6
2
4
5

比较 std::wstring 类型的实例很好。

#include <iostream>
#include <chaiscript/chaiscript.hpp>
#include <chaiscript/chaiscript_stdlib.hpp>
#include <chaiscript/dispatchkit/bootstrap_stl.hpp>

int main()
{
    chaiscript::ChaiScript chai(chaiscript::Std_Lib::library());

    chai.add(chaiscript::bootstrap::standard_library::string_type<std::wstring>("wstring"));

    std::cout << chai.eval<std::function<int (std::wstring, std::wstring)> >(
        "fun(s, t){"
        "   if(s==t){"
        "       print(\"1\");"
        "   }"
        "   return 3;"
        "}"
    )(std::wstring(L"abcd"), std::wstring(L"abaa"));

    return 0;
}

D:\TestWork\test_chaiscript>t5
3

比较 wchar_t 类型的实例不起作用。

是否必须添加比较运算符方法？

        "   if(s[1]==t[1]){"
        "       print(\"2\");"
        "   }"

D:\TestWork\test_chaiscript>t5
terminate called after throwing an instance of 'chaiscript::exception::eval_error'
  what():  Error: "Error with numeric operator calling: =="

将 std::wstring 类型的实例与字符串类型的文字进行比较是行不通的。我无法输入 wstring 类型的文字。

是否可以在 ChaiScript 中输入 wstring 类型的文字？

        "   if(s==\"aaaa\"){"
        "       print(\"2\");"
        "   }"

D:\TestWork\test_chaiscript>t5
terminate called after throwing an instance of 'chaiscript::exception::eval_error'
  what():  Error: "Can not find appropriate '==' operator." With parameters: (wstring, const string)

将 wchar_t 类型的实例与 wchar_t 类型的文字进行比较是行不通的。我无法输入 wchat_t 类型的文字。

是否可以在 ChaiScript 中输入 wchat_t 类型的文字？

        "   if(s[1]=='b'){"
        "       print(\"2\");"
        "   }"

D:\TestWork\test_chaiscript>t5
terminate called after throwing an instance of 'chaiscript::exception::eval_error'
  what():  Error: "Error with numeric operator calling: =="
4

2 回答 2

0

是的，您需要告诉 ChaiScript 一些关于的信息wchar_t，例如==操作符。例如：

chai.add(
  chaiscript::fun<bool (wchar_t, wchar_t)>(
    [](wchar_t lhs, wchar_t rhs) { return lhs == rhs; }
  ), "=="
);
于 2015-06-17T01:05:16.683 回答
0

我认为 ChaiScript 需要原生支持 wchar_t。

“调用数字运算符时出错：”在 chaiscript_eval.hpp 中生成异常。

如果变量的类型是算术，则调用 Boxed_Number::do_oper()。

// chaiscript_eval.hpp, line 98
if (t_oper != Operators::invalid && t_lhs.get_type_info().is_arithmetic() && t_rhs.get_type_info().is_arithmetic())
{
  // If it's an arithmetic operation we want to short circuit dispatch
  try{
    return Boxed_Number::do_oper(t_oper, t_lhs, t_rhs);
  } catch (const chaiscript::exception::arithmetic_error &) {
    throw;
  } catch (...) {
    throw exception::eval_error("Error with numeric operator calling: " + t_oper_string);
  }
} else {

似乎使用 std::is_arithmetic 来确定是否算术类型。

// type_info.hpp, 133 line
struct Get_Type_Info
{
    typedef T type;

     static Type_Info get()
    {
      return Type_Info(std::is_const<typename std::remove_pointer<typename std::remove_reference<T>::type>::type>::value, std::is_reference<T>::value, std::is_pointer<T>::value, 
          std::is_void<T>::value,
          std::is_arithmetic<T>::value && !std::is_same<typename std::remove_const<T>::type, bool>::value,
          &typeid(T), 
          &typeid(typename Bare_Type<T>::type));
    }
};

wchat_t 是算术类型。

std::cout << std::is_arithmetic<wchar_t>::value << std::endl;
std::cout << std::is_arithmetic<std::string>::value << std::endl;

D:\TestWork\test_chaiscript>t5.exe
1
0

如果类型是算术，则调用 Boxed_Value 的 oper() 方法。但是， oper() 方法不支持 wchar_t 类型。

// boxed_number.hpp, 295 line
inline static Boxed_Value oper(Operators::Opers t_oper, const Boxed_Value &t_lhs, const Boxed_Value &t_rhs)
{
  const Type_Info &inp_ = t_lhs.get_type_info();

  if (inp_ == typeid(int)) {
    return oper_rhs<int>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(double)) {
    return oper_rhs<double>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(long double)) {
    return oper_rhs<long double>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(float)) {
    return oper_rhs<float>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(char)) {
    return oper_rhs<char>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(unsigned int)) {
    return oper_rhs<unsigned int>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(long)) {
    return oper_rhs<long>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(unsigned long)) {
    return oper_rhs<unsigned long>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(std::int8_t)) {
    return oper_rhs<std::int8_t>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(std::int16_t)) {
    return oper_rhs<std::int16_t>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(std::int32_t)) {
    return oper_rhs<std::int32_t>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(std::int64_t)) {
    return oper_rhs<std::int64_t>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(std::uint8_t)) {
    return oper_rhs<std::uint8_t>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(std::uint16_t)) {
    return oper_rhs<std::uint16_t>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(std::uint32_t)) {
    return oper_rhs<std::uint32_t>(t_oper, t_lhs, t_rhs);
  } else if (inp_ == typeid(std::uint64_t)) {
    return oper_rhs<std::uint64_t>(t_oper, t_lhs, t_rhs);
  } else  {
    throw chaiscript::detail::exception::bad_any_cast();
  }
}

我在所有使用 inp == typeid(char) 的地方添加了支持 wchar_t 类型的代码，如下所示。

} else if (inp_ == typeid(char)) {
    return go<LHS, char>(t_oper, t_lhs, t_rhs);
} else if (inp_ == typeid(wchar_t)) {
    return go<LHS, wchar_t>(t_oper, t_lhs, t_rhs);
} else if (inp_ == typeid(unsigned int)) {

我的测试代码运行良好。 

std::cout << chai.eval<std::function<int (wchar_t a, wchar_t b)> >(
    "fun(a, b){"
    "   if(a==b){"
    "       print(\"2\");"
    "   }"
    "   return 3;"
    "}"
)(wchar_t(L'a'), wchar_t(L'a'));

D:\TestWork\test_chaiscript>t5.exe
2
3
于 2015-06-18T09:05:05.310 回答