Currying
Below is the code snippet illustrating how to implement multi-argument functions using lambdas and back:
// Let's take a 3 argument function
const foo = (x, y, z) => x + y + z;
// This function can be curried, i.e., it can be implemented using
// single-argument functions:
const foo_curried = (x) => (y) => (z) => x + y +z;
// a single argument function can always be used to implement a
// multiple-argument functions:
const foo_uncurried = (x,y,z) => foo_curried(x)(y)(z);
// all the foo's are equivalent:
// the only thing thatchanges is how we call the function
console.log(foo(1,2,3));
console.log(foo_curried(1)(2)(3));
console.log(foo_uncurried(1,2,3));
In a language with only sigle-argument lambdas, you can add syntactic sugar to implement multiple-argument functions:
Function declaration:
(x1,x2,x3,...,xn) => egets transformed to(x1) => (x2) => (x3) => ... => (xn) => eFunction application:
f(e1, e2, e3, ..., en)gets transformed tof(e1)(e2)(e3)...(en)