cpp.react/examples/src/BasicComposition.cpp at master · TheKK/cpp.react · GitHub

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// Copyright Sebastian Jeckel 2017.

// 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/state.h"

#include "react/event.h"

#include "react/observer.h"

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

/// Example 1 - Reactive class members

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

namespace example1

{

using namespace std;

using namespace react;

Group g;

class Shape

{

public:

StateVar<int> width = StateVar<int>::Create(g, 0);

StateVar<int> height = StateVar<int>::Create(g, 0);

State<int> size = State<int>::Create(g, CalcSize, width, height);

auto GetReactiveMembers() const -> decltype(auto)

{ return std::tie(width, height, size); }

private:

static int CalcSize(int w, int h)

{ return w * h; }

};

void Run()

{

cout << "Example 1 - Reactive class members" << endl;

auto myShape = ObjectState<Shape>::Create(g, Shape());

auto obs = Observer::Create([] (const auto& ctx)

{

const Shape& shape = ctx.GetObject();

cout << "Size is " << ctx.Get(shape.size) << endl;

}, myShape);

g.DoTransaction([&]

{

myShape->width.Set(4);

myShape->height.Set(4);

}); // output: Size changed to 16

cout << endl;

}

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

/// Example 2 - Slots

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

namespace example2

{

using namespace std;

using namespace react;

Group g;

class Company

{

public:

StateVar<string> name;

Company(const char* name) :

name( StateVar<string>::Create(g, name) )

{ }

bool operator==(const Company& other) const

{ return name == other.name; }

};

class Employee

{

public:

StateSlot<string> myCompanyName;

Employee(const Company& company) :

myCompanyName( StateSlot<string>::Create(company.name) )

{ }

void SetCompany(const Company& company)

{ myCompanyName.Set(company.name); }

};

void Run()

{

cout << "Example 2 - Slots" << endl;

Company company1( "MetroTec" );

Company company2( "ACME" );

Employee alice( company1 );

auto obs = Observer::Create([] (const string& name)

{

cout << "Alice now works for " << name << endl;

}, alice.myCompanyName);

company1.name.Set(string( "ModernTec" )); // output: Alice now works for ModernTec

alice.SetCompany(company2); // output: Alice now works for ACME

company2.name.Set(string( "A.C.M.E." )); // output: Alice now works for A.C.M.E.

cout << endl;

}

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

/// Run examples

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

int main()

{

example1::Run();

example2::Run();

return 0;

}

cpp.react/examples/src/BasicComposition.cpp at master · TheKK/cpp.react · GitHub

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