compare std::wstring type and represent of wstring literal in ChaiScript - wstring

Question

I want to write ChaiScript code using std::wstring type like below c++ code.
#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
To compare the instances of std::wstring type is good.
#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
To compare the instances of wchar_t type doesn't work.
Do the compare operator method must be added?
" 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: =="
To compare the instance of std::wstring type with the literal of string type doesn't work.
I cannot input the literal of wstring type.
Is it possible to input the literal of wstring type in ChaiScript?
" 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)
To compare the instance of wchar_t type with the literal of wchar_t type doesn't work.
I cannot input the literal of wchat_t type.
Is it possible to input the literal of wchat_t type in ChaiScript?
" 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: =="

Answer 1

Yes, you will need to tell ChaiScript something about wchar_t, such as the == operator. For example:
chai.add(
chaiscript::fun<bool (wchar_t, wchar_t)>(
[](wchar_t lhs, wchar_t rhs) { return lhs == rhs; }
), "=="
);

Answer 2

I think that the native support wchar_t need in ChaiScript.
"Error with numeric operator calling: " exception is generated in chaiscript_eval.hpp.
If the type of variable is arithmetic, Boxed_Number::do_oper() is called.
// 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 {
It seems to use std::is_arithmetic to determine whether arithmetic type or not.
// 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 is the arithmetic type.
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
If the type is arithmetic, oper() method for Boxed_Value is called.
But, wchar_t type is not supported in oper() method.
// 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();
}
}
I add the code to support wchar_t type like below in all place used inp == typeid(char).
} 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)) {
My test code works well.
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