cpp.react/examples/src/BasicEvents.cpp at master · zengyuxing007/cpp.react · GitHub

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// Copyright Sebastian Jeckel 2014.

// Distributed under the Boost Software License, Version 1.0.

// (See accompanying file LICENSE_1_0.txt or copy at

// http://www.boost.org/LICENSE_1_0.txt)

#include <iostream>

#include <string>

#include <utility>

#include "react/Domain.h"

#include "react/Event.h"

#include "react/Observer.h"

///////////////////////////////////////////////////////////////////////////////////////////////////

/// Example 1 - Hello world

///////////////////////////////////////////////////////////////////////////////////////////////////

namespace example1

{

using namespace std;

using namespace react;

// Defines a domain.

// Each domain represents a separate dependency graph, managed by a dedicated propagation engine.

// Reactives of different domains can not be combined.

REACTIVE_DOMAIN(D, sequential)

// Define type aliases for the given domain in this namespace.

// Now we can use EventSourceT instead of D::EventSourceT.

USING_REACTIVE_DOMAIN(D)

// An event source that emits values of type string

namespace v1

{

EventSourceT<string> mySource = MakeEventSource<D,string>();

void Run()

{

cout << "Example 1 - Hello world (string source)" << endl;

Observe(mySource, [] (const string& s) {

std::cout << s << std::endl;

});

mySource << string("Hello world #1");

// Or without the operator:

mySource.Emit(string("Hello world #2"));

// Or as a function call:

mySource(string("Hello world #3"));

cout << endl;

}

// An event source without an explicit value type

namespace v2

{

EventSourceT<> helloWorldTrigger = MakeEventSource<D>();

void Run()

{

cout << "Example 1 - Hello world (token source)" << endl;

int count = 0;

Observe(helloWorldTrigger, [&] (Token) {

cout << "Hello world #" << ++count << endl;

});

helloWorldTrigger.Emit();

// Or without the stream operator:

helloWorldTrigger << Token::value;

// Or as a function call:

helloWorldTrigger();

cout << endl;

}

///////////////////////////////////////////////////////////////////////////////////////////////////

/// Example 2 - Merging event streams

///////////////////////////////////////////////////////////////////////////////////////////////////

namespace example2

{

using namespace std;

using namespace react;

REACTIVE_DOMAIN(D, sequential)

USING_REACTIVE_DOMAIN(D)

// An event stream that merges both sources

namespace v1

{

EventSourceT<> leftClick = MakeEventSource<D>();

EventSourceT<> rightClick = MakeEventSource<D>();

EventsT<> anyClick = Merge(leftClick, rightClick);

void Run()

{

cout << "Example 2 - Merging event streams (Merge)" << endl;

int count = 0;

Observe(anyClick, [&] (Token) {

cout << "clicked #" << ++count << endl;

});

leftClick.Emit(); // output: clicked #1

rightClick.Emit(); // output: clicked #2

cout << endl;

}

// Using overloaded operator | instead of explicit Merge

namespace v2

{

EventSourceT<> leftClick = MakeEventSource<D>();

EventSourceT<> rightClick = MakeEventSource<D>();

EventsT<> anyClick = leftClick | rightClick;

void Run()

{

cout << "Example 2 - Merging event streams (operator)" << endl;

int count = 0;

Observe(anyClick, [&] (Token) {

cout << "clicked #" << ++count << endl;

});

leftClick.Emit(); // output: clicked #1

rightClick.Emit(); // output: clicked #2

cout << endl;

}

///////////////////////////////////////////////////////////////////////////////////////////////////

/// Example 3 - Filtering events

///////////////////////////////////////////////////////////////////////////////////////////////////

namespace example3

{

using namespace std;

using namespace react;

REACTIVE_DOMAIN(D, sequential)

USING_REACTIVE_DOMAIN(D)

EventSourceT<int> numbers = MakeEventSource<D,int>();

EventsT<int> greater10 = Filter(numbers, [] (int n) {

return n > 10;

});

void Run()

{

cout << "Example 3 - Filtering events" << endl;

Observe(greater10, [] (int n) {

cout << n << endl;

});

numbers << 5 << 11 << 7 << 100; // output: 11, 100

cout << endl;

}

///////////////////////////////////////////////////////////////////////////////////////////////////

/// Example 4 - Filtering events

///////////////////////////////////////////////////////////////////////////////////////////////////

namespace example4

{

using namespace std;

using namespace react;

REACTIVE_DOMAIN(D, sequential)

USING_REACTIVE_DOMAIN(D)

// Data types

enum class ETag { normal, critical };

using TaggedNum = pair<ETag,int>;

EventSourceT<int> numbers = MakeEventSource<D,int>();

EventsT<TaggedNum> tagged = Transform(numbers, [] (int n) {

if (n > 10)

return TaggedNum( ETag::critical, n );

else

return TaggedNum( ETag::normal, n );

});

void Run()

{

cout << "Example 4 - Transforming events" << endl;

Observe(tagged, [] (const TaggedNum& t) {

if (t.first == ETag::critical)

cout << "(critical) " << t.second << endl;

else

cout << "(normal) " << t.second << endl;

});

numbers << 5; // output: (normal) 5

numbers << 20; // output: (critical) 20

cout << endl;

}

///////////////////////////////////////////////////////////////////////////////////////////////////

/// Example 5 - Queuing multiple inputs

///////////////////////////////////////////////////////////////////////////////////////////////////

namespace example5

{

using namespace std;

using namespace react;

REACTIVE_DOMAIN(D, sequential)

USING_REACTIVE_DOMAIN(D)

EventSourceT<int> src = MakeEventSource<D,int>();

void Run()

{

cout << "Example 5 - Queuing multiple inputs" << endl;

Observe(src, [] (int v) {

cout << v << endl;

}); // output: 1, 2, 3, 4

DoTransaction<D>([] {

src << 1 << 2 << 3;

src << 4;

});

cout << endl;

}

///////////////////////////////////////////////////////////////////////////////////////////////////

/// Run examples

///////////////////////////////////////////////////////////////////////////////////////////////////

int main()

{

example1::v1::Run();

example1::v2::Run();

example2::v1::Run();

example2::v2::Run();

example3::Run();

example4::Run();

example5::Run();

return 0;

}

cpp.react/examples/src/BasicEvents.cpp at master · zengyuxing007/cpp.react · GitHub

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