Anonymous function facts for kids
In computer science and mathematics, an anonymous function is a function with no name. Usually, a function is written like: . It can be written anonymously as . Anonymous functions exist in most functional programming languages and most other programming languages where functions are values.
Contents
Examples in some programming languages
Each of these examples show a nameless function that multiplies two numbers.
Python
Uncurried (not curried):
(lambda x, y: x * y)
Curried:
(lambda x: (lambda y: x * y))
When given two numbers:
>>>(lambda x: (lambda y: x * y)) (3) (4)
12
Haskell
Curried:
\x -> \y -> x * y
\x y -> x * y
When given two numbers:
>>> (\x -> \y -> x * y) 3 4
12
The function can also be written in point-free (tacit) style:
(*)
Standard ML
Uncurried:
fn (x, y) => x * y
Curried:
fn x => fn y => x * y
Point-free:
(op *)
JavaScript
Uncurried:
(x, y) => x * y
function (x, y) {
return x * y;
}
Curried:
x => y => x * y
function (x) {
return function (y) {
return x * y;
};
}
Scheme
Uncurried:
(lambda (x y) (* x y))
Curried:
(lambda (x) (lambda (y) (* x y)))
Point-free:
C++ 11
Uncurried:
[](int x, int y)->int
{
return x * y;
};
Curried:
[](int x)
{
return [=](int y)->int
{
return x * y;
};
};
C++ Boost
Uncurried:
_1 * _2
Note: What you need to write boost lambda is to include <boost/lambda/lambda.hpp> header file, and using namespace boost::lambda, i.e.
#include <boost/lambda/lambda.hpp>
using namespace boost::lambda;
Related pages
See also
In Spanish: Expresión lambda para niños