Building a Toy Lexer in Ruby

Lexers are magical. They take your messy, hand-typed, human text, and convert it into a clean data structure that the computer can process. Every time you run a ruby program, use structured search or type in a date by hand, you'll find a lexer hard at work. In this article, Alex Braha Stoll pulls back the curtain to show us how lexers work and how to implement one for a simple programming language.