The Reactive Extensions for C++ (RxCpp) is a library of algorithms for values-distributed-in-time. The Range-v3 library does the same for values-distributed-in-space.
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Usage
RxCpp is a header-only C++ library that only depends on the standard library. The CMake build generates documentation and unit tests. The unit tests depend on a git submodule for the Catch library.
Example
Add Rx/v2/src
to the include paths
#include "rxcpp/rx.hpp"
namespace Rx {
using namespace rxcpp;
using namespace rxcpp::sources;
using namespace rxcpp::operators;
using namespace rxcpp::util;
}
using namespace Rx;
#include <regex>
#include <random>
using namespace std;
using namespace std::chrono;
int main()
{
random_device rd; // non-deterministic generator
mt19937 gen(rd());
uniform_int_distribution<> dist(4, 18);
// for testing purposes, produce byte stream that from lines of text
auto bytes = range(0, 10) |
flat_map([&](int i){
auto body = from((uint8_t)('A' + i)) |
repeat(dist(gen)) |
as_dynamic();
auto delim = from((uint8_t)'\r');
return from(body, delim) | concat();
}) |
window(17) |
flat_map([](observable<uint8_t> w){
return w |
reduce(
vector<uint8_t>(),
[](vector<uint8_t> v, uint8_t b){
v.push_back(b);
return v;
}) |
as_dynamic();
}) |
tap([](const vector<uint8_t>& v){
// print input packet of bytes
copy(v.begin(), v.end(), ostream_iterator<long>(cout, " "));
cout << endl;
});
//
// recover lines of text from byte stream
//
auto removespaces = [](string s){
s.erase(remove_if(s.begin(), s.end(), ::isspace), s.end());
return s;
};
// create strings split on \r
auto strings = bytes |
concat_map([](vector<uint8_t> v){
string s(v.begin(), v.end());
regex delim(R"/(\r)/");
cregex_token_iterator cursor(&s[0], &s[0] + s.size(), delim, {-1, 0});
cregex_token_iterator end;
vector<string> splits(cursor, end);
return iterate(move(splits));
}) |
filter([](const string& s){
return !s.empty();
}) |
publish() |
ref_count();
// filter to last string in each line
auto closes = strings |
filter(
[](const string& s){
return s.back() == '\r';
}) |
Rx::map([](const string&){return 0;});
// group strings by line
auto linewindows = strings |
window_toggle(closes | start_with(0), [=](int){return closes;});
// reduce the strings for a line into one string
auto lines = linewindows |
flat_map([&](observable<string> w) {
return w | start_with<string>("") | sum() | Rx::map(removespaces);
});
// print result
lines |
subscribe<string>(println(cout));
return 0;
}
Reactive Extensions
The ReactiveX Observable model allows you to treat streams of asynchronous events with the same sort of simple, composable operations that you use for collections of data items like arrays. It frees you from tangled webs of callbacks, and thereby makes your code more readable and less prone to bugs.
Credit ReactiveX.io
Other language implementations
Resources
- Intro
- Tutorials
- Marble Diagrams
- twitter stream analysis app
- Algorithm Design For Values Distributed In Time
Cloning RxCpp
RxCpp uses a git submodule (in ext/catch
) for the excellent Catch library. The easiest way to ensure that the submodules are included in the clone is to add --recursive
in the clone command.
git clone --recursive https://github.com/ReactiveX/RxCpp.git
cd RxCpp
Installing
To install RxCpp into your OS you need to follow standart procedure:
mkdir build
cd build
cmake ..
make install
If you're using the vcpkg dependency manager, you can install RxCpp using a single one-line command:
vcpkg install rxcpp
Vcpkg will acquire RxCpp, build it from source in your computer, and provide CMake integration support for your projects.
See the vcpkg repository for more information.
Importing
After you have successfully installed RxCpp you can import it into any project by simply adding to your CMakeLists.txt:
find_package(rxcpp CONFIG)
Building RxCpp Unit Tests
- RxCpp is regularly tested on OSX and Windows.
- RxCpp is regularly built with Clang, Gcc and VC
- RxCpp depends on the latest compiler releases.
RxCpp uses CMake to create build files for several platforms and IDE's
ide builds
XCode
mkdir projects/build
cd projects/build
cmake -G"Xcode" -DRXCPP_DISABLE_TESTS_AND_EXAMPLES=0 ../CMake -B.
Visual Studio 2017
mkdir projects\build
cd projects\build
cmake -G "Visual Studio 15" -DRXCPP_DISABLE_TESTS_AND_EXAMPLES=0 ..\CMake\
msbuild Project.sln
makefile builds
OSX
mkdir projects/build
cd projects/build
cmake -G"Unix Makefiles" -DCMAKE_BUILD_TYPE=RelWithDebInfo -DRXCPP_DISABLE_TESTS_AND_EXAMPLES=0 -B. ../CMake
make
Linux --- Clang
mkdir projects/build
cd projects/build
cmake -G"Unix Makefiles" -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_EXE_LINKER_FLAGS="-stdlib=libc++" -DRXCPP_DISABLE_TESTS_AND_EXAMPLES=0 -B. ../CMake
make
Linux --- GCC
mkdir projects/build
cd projects/build
cmake -G"Unix Makefiles" -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DCMAKE_BUILD_TYPE=RelWithDebInfo -DRXCPP_DISABLE_TESTS_AND_EXAMPLES=0 -B. ../CMake
make
Windows
mkdir projects\build
cd projects\build
cmake -G"NMake Makefiles" -DCMAKE_BUILD_TYPE=RelWithDebInfo -DRXCPP_DISABLE_TESTS_AND_EXAMPLES=0 -B. ..\CMake
nmake
The build only produces test and example binaries.
Running tests
- You can use the CMake test runner
ctest
- You can run the test binaries directly
rxcpp_test_*
- Tests can be selected by name or tag Example of by-tag
rxcpp_test_subscription [perf]
Documentation
RxCpp uses Doxygen to generate project documentation.
When Doxygen+Graphviz is installed, CMake creates a special build task named doc
. It creates actual documentation and puts it to projects/doxygen/html/
folder, which can be published to the gh-pages
branch. Each merged pull request will build the docs and publish them.
Contributing Code
Before submitting a feature or substantial code contribution please discuss it with the team and ensure it follows the product roadmap. Note that all code submissions will be rigorously reviewed and tested by the Rx Team, and only those that meet an extremely high bar for both quality and design/roadmap appropriateness will be merged into the source.
Microsoft Open Source Code of Conduct
This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.