Master PHP.

A shell is a command-line interface that executes commands and manages processes. In this challenge, you'll build your own POSIX compliant shell that's capable of interpreting shell commands, running external programs and builtin commands like cd, pwd, echo and more.

Along the way, you'll learn about shell command parsing, REPLs, builtin commands, and more.

Learn about regular expressions and how they're evaluated. Implement your own version of grep in PHP.

This challenge follows the book Crafting Interpreters by Robert Nystrom.

In this challenge you'll build an interpreter for Lox, a simple scripting language. Along the way, you'll learn about tokenization, ASTs, tree-walk interpreters and more.

Before starting this challenge, make sure you've read the "Welcome" part of the book that contains these chapters:

• Introduction (chapter 1)
• A Map of the Territory (chapter 2)
• The Lox Language (chapter 3)

These chapters don't involve writing code, so they won't be covered in this challenge. This challenge will start from chapter 4, Scanning.

Discover concurrent programming in PHP while also learning about TCP servers, network programming, and the Redis Protocol.