ChaiScript/ChaiScript

Embedded Scripting Language Designed for C++

Adam Brown

@Wavesonics

var running = true;
while(running)
{
    printRaw("/");
    var line = readLine();
    if(line == "exit")
    {
        running = false;
        print("Good bye.");
    }
    else
    {
        var status = run(line);
        print(status);
        if(status == 0)
        {
            print("Success");
        }
        else
        {
            print("Program returned error");
        }
    }
}

int ChaiOs::run(const string& path)
{
    if(fileExists(path))
    {
        try
        {
            auto script = loadScript(path);
            int r = chai.eval<int>(script);

            return r;
        }
        catch(chaiscript::exception::eval_error& e)
        {
            cout << "eval_error: " << endl << e.pretty_print();
            return 1;
        }
        catch(chaiscript::exception::bad_boxed_cast& e)
        {
            cout << "bad_boxed_cast" << endl << e.what();
            return 1;
        }
    }
    else
    {
        cout << "Program not found" << endl;
        return 1;
    }
}

here's the test script it's loading:

printRaw("Test Program, type something:");

var input = readLine();
print("You entered: " + input);

return 0;

Pat Callahan

@callahanp

hmm.just ran into chaiscript for the first time.

Douglas Tinkham

@dtinkham_gitlab

Just ran across this. If I have a c++ app, for example a Qt gui app, I could have a text control where users write chaiscript code (or opens existing chaiscript files) that calls my C++ functions inside my app. Is this correct?

jhihn

@jhihn

@dtinkham_gitlab , why would you do that when Qt already has a JS engine?

or, PyQt (or PySide2)

Douglas Tinkham

@dtinkham_gitlab

Why? Because I didn't know qt had js or pyqt that would do such things. I'll have a look.

Daniel Brunner

@0xFEEDC0DE64

Hi, I am trying to embed chaiscript in a small microcontroller (ESP32) and I have problems while compiling

I do not have rtti, there is simply not enough space on the flash

Can I use ChaiScript without all the dynamic_casts all over the place?

Ambrase

@Ambrase

Hello, I'm working on an app where users provide a script function that is executed with objects that I get from my infrastructure. Can I limit the execution time of the user's script and its memory consumption? I assume for the memory limit I can override STL in ChaiScript with a custom allocator. But I have no idea about the execution time limit. Is it possible? Thanks

Branimir Malesevic

@penumbra23

Hi all!

I have a question regarding the chai embedded interpreter in C++. Is there any kind of environment/isolation/sandbox (milion of names) while doing eval so that the objects/variables/functions declared inside the script reside only in the environment?

Example would be

auto script = R("
hp = 10";
def attack() { hp -= 5; }
");

chai.eval(script, env1);
chai.eval(script, env2);

chai.eval("attack()", env1);

assert.true(env1["hp"], 5);
assert.true(env2["hp"], 10);

Tony

@DigDyn

Is chaiscript dead? -- Seems no new version for 2 1/2 years.

Tony

@DigDyn

Seems even more dead, if my question gets no response in a month.

linweiyang

@linweiyang

Does anyone know how to compile the chai script file to be another file to protect programmers’ code.

Does anyone know how to compile the chai script file to be another file to protect programmers’ code?

Patrick Mulder

@mulderp

hello, i was wondering how to pass a map from chaiscript language to a c++ function

AI-Messiah

@AI-Messiah

How do I pass a Chaiscript vector to and from my C++ classes and functions

daneldanel

@daneldanel

6.1.0 is compatible with c++17 from VS2019?

A default console project in VS2019, append #include "chaiscript/chaiscript.hpp" in the main.cpp and build

the result: many warnings

Rebuild started...
1>------ Rebuild All started: Project: test_chai, Configuration: Debug Win32 ------
1>test_chai.cpp
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(2575,23): warning C4244: 'argument': conversion from 'const wchar_t' to 'const _Elem', possible loss of data
1> with
1> [
1> _Elem=char
1> ]
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(2586): message : see reference to function template instantiation 'void std::basic_string<char,std::char_traits<char>,std::allocator<char>>::_Construct<const wchar_t*>(_Iter,const _Iter,std::input_iterator_tag)' being compiled
1> with
1> [
1> _Iter=const wchar_t
1> ]
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(2586): message : see reference to function template instantiation 'void std::basic_string<char,std::char_traits<char>,std::allocator<char>>::_Construct<const wchar_t>(_Iter,const _Iter,std::input_iterator_tag)' being compiled
1> with
1> [
1> _Iter=const wchar_t
1> ]
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(2566): message : see reference to function template instantiation 'void std::basic_string<char,std::char_traits<char>,std::allocator<char>>::_Construct<const wchar_t>(const _Iter,const _Iter,std::forward_iterator_tag)' being compiled
1> with
1> [
1> _Iter=const wchar_t
1> ]
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(2566): message : see reference to function template instantiation 'void std::basic_string<char,std::char_traits<char>,std::allocator<char>>::_Construct<const wchar_t>(const _Iter,const _Iter,std::forward_iterator_tag)' being compiled
1> with
1> [
1> _Iter=const wchar_t *
1> ]
1>D:\work\src\3rdparty\ChaiScript-6.1.0\include\chaiscript\language\chaiscript_windows.hpp(36): message : see reference to function template instantiation 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>::basic_string<std::_String_const_iterator<std::_String_val<std::_Simple_types<_Elem>>>,0>(_Iter,_Iter,const _Alloc &)' being compiled
1> with
1> [
1> _Elem=wchar_t,
1> _Iter=std::_String_const_iterator<std::_String_val<std::_Simple_types<wchar_t>>>,
1> _Alloc=std::allocator<char>
1> ]
1>D:\work\src\3rdparty\ChaiScript-6.1.0\include\chaiscript\language\chaiscript_windows.hpp(36): message : see reference to function template instantiation 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>::basic_string<std::_String_const_iterator<std::_String_val<std::_Simple_types<_Elem>>>,0>(_Iter,_Iter,const _Alloc &)' being compiled
1> with
1> [
1> _Elem=wchar_t,
1> _Iter=std::_String_const_iterator<std::_String_val<std::_Simple_types<wchar_t>>>,
1> _Alloc=std::allocator<char>
1> ]
1>D:\work\src\3rdparty\ChaiScript-6.1.0\include\chaiscript\language\chaiscript_windows.hpp(78): message : see reference to function template instantiation 'std::string chaiscript::detail::Loadable_Module::to_string<std::wstring>(const T &)' being compiled
1> with
1> [
1> T=std::wstring
1> ]
1>test_chai.vcxproj -> D:\work\src\test\test_chai\Debug\test_chai.exe
1>Done building project "test_chai.vcxproj".
========== Rebuild All: 1 succeeded, 0 failed, 0 skipped ==========

the code is dummy:

include "chaiscript/chaiscript.hpp"

include <iostream>

int main()
{
std::cout << "Hello World!\n";
}

daneldanel

@daneldanel

for me, default settings must be with Warning Level: Level4 (/W4) and Threat Warnings as Error: true

so, the dummy project will never compile

daneldanel

@daneldanel

the problem is in static std::string get_error_message(DWORD t_err) if defined UNICODE

return to_string(retval); ehre retval is a wchar_t*

and

template<typename T>
static std::string to_string(const T &t_str)
{
return std::string(t_str.begin(), t_str.end());
}

if T=wchar_t then the result is malformed

daneldanel

@daneldanel

in Windows, for wchar_t to char conversion you must use WideCharToMultiByte and for char to wchar_t MultiByteToWideChar

NamelessHoodie

@NamelessHoodie

Is there any way in chaiscript to pass a c++ object to chaiscript. As an example as the argument for a function?

That back and forth passing of objects between cpp and the scripting language is something I really need.

Additionally, is chai script multi threaded? Is there any threading support? That's particularly important for events.

Sorry for the questions, wasn't able to deduct this information from the wiki.

namelesshoodie

@namelesshoodie:matrix.org

[m]

Well, please let me know if anyone knows anything about it.

stellarpower

@stellarpower

You can pass an object using chaiscript::var

https://github.com/ChaiScript/ChaiScript/blob/develop/cheatsheet.md#adding-objects

1 reply

On that note, could anytone tell me please if I can retrieve an arbitrary variable defined in the script file? If I have an object called v in the script, so far the only way I can see to do this is chai.boxed_cast<SomeType>(chai.eval("v"));

1 reply

stellarpower

@stellarpower

@namelesshoodie:matrix.org ^^ forgot to ping

stellarpower

@stellarpower

It'll do for now, at least I suppose.

And no worries

stellarpower

@stellarpower

Is there a way I can get a property of a chai object by its name (as a string), inside chai itself?

I.e.

auto x = SomeType()
auto a = x.property("count"); auto b  = x.count
print(a.to_string() + " == " + b.to_string)

stellarpower

@stellarpower

I see that the reflection module was removed some time ago. Is there some sort of alternative?

Or even just to get the type of an object? It's hard to debug dispatch issues, I have occasions when the backtrace I get from the eval exception isn't quite correct, and I also don't know what types my variables have been resolved to. I had something funky with a pair yesterday, where the instantiation hadn't been bootstrapped.

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include "chaiscript/chaiscript.hpp"

include <iostream>