First-class functions can be assigned to variables, passed to other functions as arguments, or returned from other functions. The ability to return a function enables deferred execution. Functions that accept other functions as arguments are called higher-order functions.
Questions tagged [first-class-functions]
132 questions
1
vote
1 answer
wrong number of arguements clojure
I'm building a program that's meant to allow users count either the number of letters or number of words in a string, however when running the program through the cmd, I'm getting a clojure.lang.ArityException, wrong number of args (1) passed to :…
Karab
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1
vote
1 answer
Is there anything python function decorators can do that I can't do with first class functions?
I'm trying to understand Python function decorators, but so far I don't see any case where a function decorator can do something I couldn't do using first class functions.
As an example, the logger decorator is often given as a simple example of a…
arnfred
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1 answer
How do i refer to a get function as an object
I'd like to reference a get function as a Function object rather than as the value that it returns.
Normally i would be able to simply refer to the function without parenthesizes like so:
private function getFoo():int {
return…
Kris Welsh
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1 answer
What exactly are First Class Functions?
I searched the web to try and understand this term. I understand that 'first class functions' are functions that can be assigned to variables and 'passed around'. But I don't actually understand what this means.
So what does it mean? What are First…
Aviv Cohn
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4 answers
Java 8 dancing around functions as first class citizens?
So the functional programmer in me likes languages like python that treat functions as first class citizens. It looks like Java 8 caved to the pressure and "sort of" implemented things like lambda expressions and method references.
My question is,…
C.B.
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1
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2 answers
What is different between First-class function and Anonymous function?
I saw two concepts
First-class function
Anonymous function
It seems that these two concepts are the same? (lambda)
I'm confused?
HamedFathi
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2 answers
Lua: how to verify that a table contains a specific function
I'm developing a module that returns a table full of functions based on the arguments that are passed in. Specifically, the module returns a set of data transformation rules (functions) that need to be applied to a data set depending on which…
Mitch A
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1 answer
Function with varargs in constructor
I am trying to get this working in Scala:
class MyClass(some: Int, func: AnyRef* => Int) {
}
The above code won't compile (why?) but the following does:
class MyClass(some: Int, func: Seq[AnyRef] => Int) {
}
That's OK but are the two equivalent?…
nobeh
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4 answers
What is the equivalent of passing functions as arguments using an object oriented approach
I have a program in python that includes a class that takes a function as an argument to the __init__ method. This function is stored as an attribute and used in various places within the class. The functions passed in can be quite varied, and…
savagent
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Using FnMut, Fn, FnOnce as arguments to a function
I don't quite understand when/how a function can use bounds of types Fn, FnOnce, FnMut. Can someone explain in what scenario these would be used and how one would use them?
As I understand it, I can create a function like this:
struct Dog {
…
SPQR
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1 answer
On the fly function expression doesn't throw error when triggering with first class
I am learning Javascript and I came across these concepts of function expressions & first class functions.
While I do understand their definition, I am unable to understand why my code behaves the way it does.
I have a first class function which…
M Navneet Krishna
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1 answer
Why are functions only sometimes first class variables in R? Using them from built-in data structures causes "Error: attempt to apply non-function"
I am trying to understand how first class functions work in R. I had understood that functions were first class in R, but was sorely disappointed when applying that understanding. When a function is saved to a list, whether that be as an ordinary…
David
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How to use std::function with template as argument
I'm trying to understand templates and I have this piece of code:
#include
#include
using namespace std;
template
bool myCompare(const T& a, const T& b) {
return a>b;
}
template
bool encCompare(const…
user2565010
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2 answers
How to write a JavaScript function that works both as a first-class function and higher-order function?
For example let's take the function add. I want to be able to call:
add(1, 2)(3, 4)
and
add(1, 2)
using same implementation.
I have tried writing the add function the following way:
var add = (a, b) => {
return (c, d) => {
return a +…
Ahmad Wehbe
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1 answer
Making a first-class Function with arguments in Python
My issue is simple: I want to make a first-class function in python that has some arguments in it.
But the problem is that to assign it, you need to call it, wich can be problematic
def print_double(num):
print(num*2)
a = print_double(4)
I…
Stepa1411
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