Gain insights into functional programming in PHP. Learn about pure functions, immutable data, and monads. Explore error handling and apply principles through practical projects.

fp15aug.tar.gz

php7.4

ch8-phonebook

php8.1

purescript

python-pytoolz

chapter5-challenge1

AMQP

eris-testing-lesson

AMQP-Challenge

eris-testing-challenge

Functional programming is a paradigm that emphasizes expressing program logic as compositions of pure functions. PHP is a good fit for functional programming as functions are first-class citizens in its userland.
 
This course introduces you to the core concepts of functional programming, like pure functions, immutable data structures, and referential transparency. From there, you'll explore ways to handle errors with default values and callbacks while also exploring sum types such as Either or Maybe. Next, you'll look at functors before diving deep into monads, including IO, State, Reader, and List.
 
By the end of this course, you'll have a keen understanding of how to apply these principles in practice through a worked-out project. Not only will you know another way to program, but you’ll also feel confident enough to apply these ideas to your projects in PHP.

Learn Functional Programming in PHP

## What’s a pure function?


A **pure function** is one free from side effects and side causes. Side effects and side causes are either caused by or cause undesirable state changes in scopes both local and foreign to a function definition.

## Side causes and side effects

A **side cause** is a product of impure input. It’s typically an input, such as a global variable used in a function body or an ORM (object-relational mapper) object specified as a function parameter. A **side effect** i is the result of impure functions. Side causes often cause side effects.

### Problem 1

Look closely at the following code snippet:

# What’s a pure function?


A **pure function** is one free from side effects and side causes. Side effects and side causes are either caused by or cause undesirable state changes in scopes both local and foreign to a function definition.

# Side causes and side effects

A **side cause** is a product of impure input. It’s typically an input, such as a global variable used in a function body or an ORM (object-relational mapper) object specified as a function parameter. A **side effect** i is the result of impure functions. Side causes often cause side effects.

## Problem 1

Look closely at the following code snippet:

Learn about pure functions, their side causes, and their side effects.

Getting Started

An Introduction to Functional Programming in PHP

Core Concepts: Functional Programming in PHP

Composition and Helper Functions

Error Handling in Functional Programming

Functors in PHP

Parallelization of Tasks in PHP

Recursion, Pattern Matching, and Property Testing

Phonebook Application — A Simple Project

Conclusion

Appendix

Pure Functions

What’s a pure function?

Side causes and side effects

Problem 1