F# Composition

Syntax

F# composition is denoted using the >> operator. Here is the syntax of F# composition:

let composedFunc = func1 >> func2 >> func3

Example

Let's say we have two functions that we want to compose:

let addOne x = x + 1
let double x = x * 2

We can compose them to create a new function that first adds one to the input and then doubles it:

let addOneAndDouble = addOne >> double

Explanation

F# composition allows you to combine multiple functions into a new function. The >> operator is used to compose functions. When you compose two functions f and g, you create a new function that applies g to the result of f.

In the example above, the addOneAndDouble function is created by composing addOne and double. When you apply addOneAndDouble to an input value, it first applies addOne to the value and then applies double to the result.

Use

F# composition is useful when you want to break down a complex function into smaller, simpler functions. You can then compose these simpler functions to create the complex function.

Composition also makes it easier to reuse code. If you have multiple functions that perform similar operations, you can compose them to avoid duplication.

Important Points

• In F# composition, the output type of one function must match the input type of the next function.
• F# composition is left associative. This means that if you have three functions to compose f, g, and h, the expression f >> g >> h is equivalent to (f >> g) >> h.
• Functions can be composed in any order. For example, you can also compose the double and addOne functions to create a new function that first doubles the input and then adds one: let doubleAndAddOne = double >> addOne.

Summary

F# composition allows you to combine multiple functions into a new function. You can use the >> operator to compose functions. Composition is useful for breaking down complex functions into simpler functions, and for reusing code. Remember that the output type of one function must match the input type of the next function, and that composition is left associative.