A Jupyter kernel for C++ based on the cling C++ interpreter and the xeus native implementation of the Jupyter protocol, xeus.
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#include <iostream>
std::cout << "some output" << std::endl;
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std::cerr << "some error" << std::endl;
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#include <stdexcept>
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throw std::runtime_error("Unknown exception");
Omitting the ; in the last statement of a cell results in an output being printed
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int j = 5;
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j
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?std::vector
For a user-defined type T, the rich rendering in the notebook and JupyterLab can be enabled by by implementing the function xeus::xjson mime_bundle_repr(const T& im), which returns the JSON mime bundle for that type.
More documentation on the rich display system of Jupyter and Xeus-cling is available at https://xeus-cling.readthedocs.io/en/latest/rich_display.html
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#include <string>
#include <fstream>
#include "xtl/xbase64.hpp"
#include "xeus/xjson.hpp"
namespace im
{
struct image
{
inline image(const std::string& filename)
{
std::ifstream fin(filename, std::ios::binary);
m_buffer << fin.rdbuf();
}
std::stringstream m_buffer;
};
xeus::xjson mime_bundle_repr(const image& i)
{
auto bundle = xeus::xjson::object();
bundle["image/png"] = xtl::base64encode(i.m_buffer.str());
return bundle;
}
}
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im::image marie("images/marie.png");
marie
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#include <string>
#include <fstream>
#include "xtl/xbase64.hpp"
#include "xeus/xjson.hpp"
namespace au
{
struct audio
{
inline audio(const std::string& filename)
{
std::ifstream fin(filename, std::ios::binary);
m_buffer << fin.rdbuf();
}
std::stringstream m_buffer;
};
xeus::xjson mime_bundle_repr(const audio& a)
{
auto bundle = xeus::xjson::object();
bundle["text/html"] =
std::string("<audio controls=\"controls\"><source src=\"data:audio/wav;base64,")
+ xtl::base64encode(a.m_buffer.str()) +
"\" type=\"audio/wav\" /></audio>";
return bundle;
}
}
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au::audio drums("audio/audio.wav");
drums
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#include "xcpp/xdisplay.hpp"
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xcpp::display(drums);
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#include <string>
#include "xcpp/xdisplay.hpp"
namespace ht
{
struct html
{
inline html(const std::string& content)
{
m_content = content;
}
std::string m_content;
};
xeus::xjson mime_bundle_repr(const html& a)
{
auto bundle = xeus::xjson::object();
bundle["text/html"] = a.m_content;
return bundle;
}
}
// A red rectangle
ht::html rect(R"(
<div style='
width: 90px;
height: 50px;
line-height: 50px;
background-color: blue;
color: white;
text-align: center;'>
Original
</div>)");
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xcpp::display(rect, "some_display_id");
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// Update the rectangle to be blue
rect.m_content = R"(
<div style='
width: 90px;
height: 50px;
line-height: 50px;
background-color: red;
color: white;
text-align: center;'>
Updated
</div>)";
xcpp::display(rect, "some_display_id", true);
Magics are special commands for the kernel that are not part of the C++ language.
They are defined with the symbol % for a line magic and %% for a cell magic.
More documentation for magics is available at https://xeus-cling.readthedocs.io/en/latest/magics.html.
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#include <algorithm>
#include <vector>
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std::vector<double> to_shuffle = {1, 2, 3, 4};
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%timeit std::random_shuffle(to_shuffle.begin(), to_shuffle.end());
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