This series is about how to write a programming language. A lexer breaks up the characters in a source file into simple “tokens” which have a type like “string” and a value.

Andy Balaam walks through the lexer of Cell, a little programming language he wrote. More info: http://www.artificialworlds.net/blog/2016/09/24/how-to-write-a-programming-language-part-1-the-lexer/