What the /^\re*[ge]+x?$/

In this project you will learn about regular expressions.

A Regular Expression is a program that matches (or fails to match) parts of a string. Regular Expressions are often found inside of other, larger programs, but in this section we'll be learning them independently. As a programming language, regexes are very concise and can be difficult to understand; try to think of it as a cipher or puzzle and have fun learning its arcane rules without worrying too much about what they're used for.

Resources for debugging Regular Expressions

Simple language matching library

This library is similar to Regular Expressions but uses more verbose word-like symbols. It's is not the same as a RegExp but can help to form the problem if you think in a more narrative way.