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

# Problem statement

In a Writer monad environment, sequential chains are log-oriented. In addition to the computed values, the Writer monad also generates useful side data.

For this challenge, some string operations are given below in the table. Your task is to log all operations in sequential chains with a Writer monad and generate side data. The encoded representations of the operations are given below in sequential order:



|**Order**|**Operation**|**Encoded representation**|
|:---:|:---|:---:|
| 1 | Placing a given string (`$str`) in an environment. | `place "$str" in environment` |
| 2  | Computing the letter count of the string (`$str`).  | `compute "$str" letter count`  |
| 3  | Squaring the letter count of the string (`$str`).  | `compute square of "$str" letter count` |

# Requirements 

Write all your logic inside a function named `WriterChallenge()`. The function must be able to take a string as a parameter and return the result of the sequential chain, along with side data.

Use the function defined below in your composition for all three operations. It returns a function that computes the value of the function `f` and logs it along with the side data `msg`.


# Problem statement

In a Writer monad environment, sequential chains are log-oriented. In addition to the computed values, the Writer monad also generates useful side data.

For this challenge, some string operations are given below in the table. Your task is to log all operations in sequential chains with a Writer monad and generate side data. The encoded representations of the operations are given below in sequential order:



|**Order**|**Operation**|**Encoded representation**|
|:---:|:---|:---:|
| 1 | Placing a given string (`＄str`) in an environment. | `place "＄str" in environment` |
| 2  | Computing the letter count of the string (`＄str`).  | `compute "＄str" letter count`  |
| 3  | Squaring the letter count of the string (`＄str`).  | `compute square of "＄str" letter count` |

# Requirements 

Write all your logic inside a function named `WriterChallenge()`. The function must be able to take a string as a parameter and return the result of the sequential chain, along with side data.

Use the function defined below in your composition for all three operations. It returns a function that computes the value of the function `f` and logs it along with the side data `msg`.


Test your knowledge by solving a problem requiring the Writer monad.

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

Challenge 2: Writer Monad

Problem statement