In object-oriented languages, function object (also known as functor) is a feature that allows objects to be used like if they were ordinary functions.
Questions tagged [function-object]
168 questions
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3 answers
Function wrapper via (function object) class (variadic) template
C++
I'm trying to implement a function wrapper via a (function object) class (variadic) template. The class has as its only data member a function pointer that is initialized by or assigned the function pointer it is wrapping. The parametrized…
CodeBricks
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1 answer
Do function decorators in python call the decorated function implicitly?
My title could be misleading. my question comes from this code snippet.
class myDecorator(object):
def __init__(self, f):
print "inside myDecorator.__init__()"
f() # Prove that function definition has completed
def…
eagertoLearn
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1
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1 answer
function object with stdout in C++
the program will run correctly if with no cout;
why?
something wrong with output cache?
#include
#include
#include
using namespace std;
class fn
{
public:
int i;
bool operator()(int,int)
{
…
tqtifnypmb
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1
vote
4 answers
Where do I define Predicates and Function Objects?
My question is of a purely organisational nature and hence I realize potential answers may be subjective in nature. After years of working with C#, I've finally returned to C++ and am struggling with getting used to how to properly organise the…
Renegade Vile
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1
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2 answers
Function objects in Haskell compile error
I'm trying to create a class Func which represents a function, and then a data type Dot which composes functions. Below is my attempt, but I'm getting compile errors:
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FunctionalDependencies #-}
{-#…
Clinton
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1
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1 answer
javascript augmented prototype and chain
I don't understand why if I add a property or function to a prototype of an existing function object that property or function is not recognized as belonging to the object.
Example:
var a = function() {};
a.prototype.c = function() {/* code…
cubob
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1
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2 answers
Parsing ambiguity in a call to a temporary function object
I suspect that in the code below, a call to a temporary function object with both a constructor argument and a function call operator argument is somehow ambiguous due to a most-vexing-parse issue.
#include
class Fun
{
public:
…
TemplateRex
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1
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2 answers
Is the classname() equivalent to a class object?
I know this might be a stupid question but I am not sure how to describe it properly.
When I try to call std::transform function for example,
template < class InputIterator, class OutputIterator, class UnaryOperator >
OutputIterator transform (…
SJinxin
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0
votes
1 answer
Dropdown box representing a method call on a string
I have a dropdown box where the user can select a method to check whether a certain string either equals or endswith another string.
I would think to use function pointers/objects as the dropdown box model and call the one currently selected, but…
Kawu
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2 answers
Is there an objective reason why the explicitly instantiated std::less, std::greater and similar offer no conversion to function pointer?
Stateless lambdas can be converted to function pointers, e.g. this is valid,
using Fun = bool(*)(int, int);
constexpr auto less = [](int a, int b){ return a < b; };
Fun f{less};
but objects like std::less{} can't.
I do understand why…
Enlico
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0
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0 answers
Problems with std::bind and std::placeholder
I'm trying to bind a function object (addWords) with two parameters (string and unsigned) but the compiler doesn't seem to like the std::placeholder.
I tried also without std::bind, calling the operator() with a std::placeholder before the for_each.…
Max Mistery
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0
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1 answer
Execution speed of code with `function` object as compared to using template functions
I know that std::function is implemented with the type erasure idiom. Type erasure is a handy technique, but as a drawback it needs to store on the heap a register (some kind of array) of the underlying objects.
Hence when creating or copying a…
Giogre
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0 answers
Attempting to use global variable in javascript Function object
Putting this at the top of my post for a little extra clarity:
The overall goal here is to build a feature for dynamic banners where you can input some custom javascript animation code through a dynamic data feed in the form of a google sheet. My…
tganyan
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Does Boost (or another library) offer a way to lift the name of a "constructor-less" class into a function object that uses aggregate initialization?
This is kind of a follow up to this question, where I asked how I could tersely turn a template and/or overloaded function into a function object.
The accepted answer was you can't do without macro, which is correct. Then I found that such a macro…
Enlico
- 23,259
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0
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1 answer
Add index signature to a function in .d.ts
I want to overwrite npm library typing to add index signature to a function. Let's say the function does nothing spectacular:
export function foo(input) {
return Number(input);
}
It has a typing in .d.ts file:
export default function foo(input:…
Buszmen
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