Simplifying the use of std::function stored in an std::vector within a class












0














I have written this basic class to store std::function<T> within std::vector<T> and I have two free function templates foo() and bar() that both return void and take a std::vector<T> as their parameter. Currently they do exactly the same for simplicity sakes; but let's say for future reference they will be doing different calculations or tasks. So far this is what I have come up with:



#include <vector>
#include <functional
#include <iostream>
#include <exception>

template<typename T>
class MyClass {
private:
std::vector<std::function<void(std::vector<T>)>> myFuncs_;
public:
MyClass() = default;

void addFunc( std::function<void(std::vector<T>)> func ) {
myFuncs_.push_back(func);
}

std::function<void(std::vector<T>)> caller(unsigned idx) {
return myFuncs_.at(idx);
}
};

template<typename T>
void foo(std::vector<T> data) {
std::cout << "foo() called:n";

for (auto& d : data)
std::cout << d << " ";
std::cout << 'n';
}

template<typename T>
void bar(std::vector<T> data) {
std::cout << "bar() called:n";

for (auto& d : data)
std::cout << d << " ";
std::cout << 'n';
}

int main() {
try {
MyClass<int> myClass;
std::vector<int> a{ 1,3,5,7,9 };
std::vector<int> b{ 2,4,6,8,10 };

std::function<void(std::vector<int>)> funcA = std::bind(foo<int>, a);
std::function<void(std::vector<int>)> funcB = std::bind(bar<int>, b);
myClass.addFunc( funcA );
myClass.addFunc( funcB );

myClass.caller(0)(a);
myClass.caller(1)(b);

} catch( std::runtime_error& e ) {
std::cerr << e.what() << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}


And this sure enough outputs:



foo() called:
1 3 5 7 9
bar() called:
2 4 6 8 10




Here's what I would like to know: is there or are there any way(s) to simplify this code; some of the syntax looks redundant, for example: In the main function after I had instantiated an instance of my class template and created an std::vector with values, I then create an instance of std::function<T> using std::bind with the function I want to then add to my class's vector. Then after binding them and adding them to my class's container, this is where I call the class's function to index the function I want to call using std::functions's operator(). However the function is expecting a std::vector<T> so it appears that I am passing this vector<T> multiple times as you can see from this part from my code above.



// std::vector<T> being passed to std::bind
std::function<void(std::vector<int>)> funcA = std::bind(foo<int>,a);
myClass.addFunc( funcA );
myClass.caller(0)(a); // Again std::vector<T> being passed but to `std::function`'s operator because the stored function requires this parameter.


Can this be simplified or is this just in the semantics of how std::function and std::bind work? If this can be simplified, would it be done within the class itself to make it easier on the user or would it be from the user side?









share






















  • foo, bar and MyClass? That looks like example code. Please separate the code under review from the examples.
    – Zeta
    2 mins ago










  • @Zeta currently foo and bar is what I am using to test my class and its use within main(). Not 100% sure as to what you are asking...
    – Francis Cugler
    52 secs ago
















0














I have written this basic class to store std::function<T> within std::vector<T> and I have two free function templates foo() and bar() that both return void and take a std::vector<T> as their parameter. Currently they do exactly the same for simplicity sakes; but let's say for future reference they will be doing different calculations or tasks. So far this is what I have come up with:



#include <vector>
#include <functional
#include <iostream>
#include <exception>

template<typename T>
class MyClass {
private:
std::vector<std::function<void(std::vector<T>)>> myFuncs_;
public:
MyClass() = default;

void addFunc( std::function<void(std::vector<T>)> func ) {
myFuncs_.push_back(func);
}

std::function<void(std::vector<T>)> caller(unsigned idx) {
return myFuncs_.at(idx);
}
};

template<typename T>
void foo(std::vector<T> data) {
std::cout << "foo() called:n";

for (auto& d : data)
std::cout << d << " ";
std::cout << 'n';
}

template<typename T>
void bar(std::vector<T> data) {
std::cout << "bar() called:n";

for (auto& d : data)
std::cout << d << " ";
std::cout << 'n';
}

int main() {
try {
MyClass<int> myClass;
std::vector<int> a{ 1,3,5,7,9 };
std::vector<int> b{ 2,4,6,8,10 };

std::function<void(std::vector<int>)> funcA = std::bind(foo<int>, a);
std::function<void(std::vector<int>)> funcB = std::bind(bar<int>, b);
myClass.addFunc( funcA );
myClass.addFunc( funcB );

myClass.caller(0)(a);
myClass.caller(1)(b);

} catch( std::runtime_error& e ) {
std::cerr << e.what() << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}


And this sure enough outputs:



foo() called:
1 3 5 7 9
bar() called:
2 4 6 8 10




Here's what I would like to know: is there or are there any way(s) to simplify this code; some of the syntax looks redundant, for example: In the main function after I had instantiated an instance of my class template and created an std::vector with values, I then create an instance of std::function<T> using std::bind with the function I want to then add to my class's vector. Then after binding them and adding them to my class's container, this is where I call the class's function to index the function I want to call using std::functions's operator(). However the function is expecting a std::vector<T> so it appears that I am passing this vector<T> multiple times as you can see from this part from my code above.



// std::vector<T> being passed to std::bind
std::function<void(std::vector<int>)> funcA = std::bind(foo<int>,a);
myClass.addFunc( funcA );
myClass.caller(0)(a); // Again std::vector<T> being passed but to `std::function`'s operator because the stored function requires this parameter.


Can this be simplified or is this just in the semantics of how std::function and std::bind work? If this can be simplified, would it be done within the class itself to make it easier on the user or would it be from the user side?









share






















  • foo, bar and MyClass? That looks like example code. Please separate the code under review from the examples.
    – Zeta
    2 mins ago










  • @Zeta currently foo and bar is what I am using to test my class and its use within main(). Not 100% sure as to what you are asking...
    – Francis Cugler
    52 secs ago














0












0








0







I have written this basic class to store std::function<T> within std::vector<T> and I have two free function templates foo() and bar() that both return void and take a std::vector<T> as their parameter. Currently they do exactly the same for simplicity sakes; but let's say for future reference they will be doing different calculations or tasks. So far this is what I have come up with:



#include <vector>
#include <functional
#include <iostream>
#include <exception>

template<typename T>
class MyClass {
private:
std::vector<std::function<void(std::vector<T>)>> myFuncs_;
public:
MyClass() = default;

void addFunc( std::function<void(std::vector<T>)> func ) {
myFuncs_.push_back(func);
}

std::function<void(std::vector<T>)> caller(unsigned idx) {
return myFuncs_.at(idx);
}
};

template<typename T>
void foo(std::vector<T> data) {
std::cout << "foo() called:n";

for (auto& d : data)
std::cout << d << " ";
std::cout << 'n';
}

template<typename T>
void bar(std::vector<T> data) {
std::cout << "bar() called:n";

for (auto& d : data)
std::cout << d << " ";
std::cout << 'n';
}

int main() {
try {
MyClass<int> myClass;
std::vector<int> a{ 1,3,5,7,9 };
std::vector<int> b{ 2,4,6,8,10 };

std::function<void(std::vector<int>)> funcA = std::bind(foo<int>, a);
std::function<void(std::vector<int>)> funcB = std::bind(bar<int>, b);
myClass.addFunc( funcA );
myClass.addFunc( funcB );

myClass.caller(0)(a);
myClass.caller(1)(b);

} catch( std::runtime_error& e ) {
std::cerr << e.what() << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}


And this sure enough outputs:



foo() called:
1 3 5 7 9
bar() called:
2 4 6 8 10




Here's what I would like to know: is there or are there any way(s) to simplify this code; some of the syntax looks redundant, for example: In the main function after I had instantiated an instance of my class template and created an std::vector with values, I then create an instance of std::function<T> using std::bind with the function I want to then add to my class's vector. Then after binding them and adding them to my class's container, this is where I call the class's function to index the function I want to call using std::functions's operator(). However the function is expecting a std::vector<T> so it appears that I am passing this vector<T> multiple times as you can see from this part from my code above.



// std::vector<T> being passed to std::bind
std::function<void(std::vector<int>)> funcA = std::bind(foo<int>,a);
myClass.addFunc( funcA );
myClass.caller(0)(a); // Again std::vector<T> being passed but to `std::function`'s operator because the stored function requires this parameter.


Can this be simplified or is this just in the semantics of how std::function and std::bind work? If this can be simplified, would it be done within the class itself to make it easier on the user or would it be from the user side?









share













I have written this basic class to store std::function<T> within std::vector<T> and I have two free function templates foo() and bar() that both return void and take a std::vector<T> as their parameter. Currently they do exactly the same for simplicity sakes; but let's say for future reference they will be doing different calculations or tasks. So far this is what I have come up with:



#include <vector>
#include <functional
#include <iostream>
#include <exception>

template<typename T>
class MyClass {
private:
std::vector<std::function<void(std::vector<T>)>> myFuncs_;
public:
MyClass() = default;

void addFunc( std::function<void(std::vector<T>)> func ) {
myFuncs_.push_back(func);
}

std::function<void(std::vector<T>)> caller(unsigned idx) {
return myFuncs_.at(idx);
}
};

template<typename T>
void foo(std::vector<T> data) {
std::cout << "foo() called:n";

for (auto& d : data)
std::cout << d << " ";
std::cout << 'n';
}

template<typename T>
void bar(std::vector<T> data) {
std::cout << "bar() called:n";

for (auto& d : data)
std::cout << d << " ";
std::cout << 'n';
}

int main() {
try {
MyClass<int> myClass;
std::vector<int> a{ 1,3,5,7,9 };
std::vector<int> b{ 2,4,6,8,10 };

std::function<void(std::vector<int>)> funcA = std::bind(foo<int>, a);
std::function<void(std::vector<int>)> funcB = std::bind(bar<int>, b);
myClass.addFunc( funcA );
myClass.addFunc( funcB );

myClass.caller(0)(a);
myClass.caller(1)(b);

} catch( std::runtime_error& e ) {
std::cerr << e.what() << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}


And this sure enough outputs:



foo() called:
1 3 5 7 9
bar() called:
2 4 6 8 10




Here's what I would like to know: is there or are there any way(s) to simplify this code; some of the syntax looks redundant, for example: In the main function after I had instantiated an instance of my class template and created an std::vector with values, I then create an instance of std::function<T> using std::bind with the function I want to then add to my class's vector. Then after binding them and adding them to my class's container, this is where I call the class's function to index the function I want to call using std::functions's operator(). However the function is expecting a std::vector<T> so it appears that I am passing this vector<T> multiple times as you can see from this part from my code above.



// std::vector<T> being passed to std::bind
std::function<void(std::vector<int>)> funcA = std::bind(foo<int>,a);
myClass.addFunc( funcA );
myClass.caller(0)(a); // Again std::vector<T> being passed but to `std::function`'s operator because the stored function requires this parameter.


Can this be simplified or is this just in the semantics of how std::function and std::bind work? If this can be simplified, would it be done within the class itself to make it easier on the user or would it be from the user side?







c++ template c++17





share












share










share



share










asked 7 mins ago









Francis Cugler

25116




25116












  • foo, bar and MyClass? That looks like example code. Please separate the code under review from the examples.
    – Zeta
    2 mins ago










  • @Zeta currently foo and bar is what I am using to test my class and its use within main(). Not 100% sure as to what you are asking...
    – Francis Cugler
    52 secs ago


















  • foo, bar and MyClass? That looks like example code. Please separate the code under review from the examples.
    – Zeta
    2 mins ago










  • @Zeta currently foo and bar is what I am using to test my class and its use within main(). Not 100% sure as to what you are asking...
    – Francis Cugler
    52 secs ago
















foo, bar and MyClass? That looks like example code. Please separate the code under review from the examples.
– Zeta
2 mins ago




foo, bar and MyClass? That looks like example code. Please separate the code under review from the examples.
– Zeta
2 mins ago












@Zeta currently foo and bar is what I am using to test my class and its use within main(). Not 100% sure as to what you are asking...
– Francis Cugler
52 secs ago




@Zeta currently foo and bar is what I am using to test my class and its use within main(). Not 100% sure as to what you are asking...
– Francis Cugler
52 secs ago















active

oldest

votes











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["\$", "\$"]]);
});
});
}, "mathjax-editing");

StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "196"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f210548%2fsimplifying-the-use-of-stdfunction-stored-in-an-stdvector-within-a-class%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown






























active

oldest

votes













active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Code Review Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.





Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


Please pay close attention to the following guidance:


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f210548%2fsimplifying-the-use-of-stdfunction-stored-in-an-stdvector-within-a-class%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Morgemoulin

Scott Moir

Souastre