Coding in Haskell | Writing and debugging megaparsec parsers for grep

A live-coding session building a grep clone from scratch in Haskell using the Megaparsec library.

Try building your own smth using CodeCrafters, my affiliate link: app.codecrafters.io/join?via=Zelenya In this tutorial, we build grep from "scratch" by following a CodeCrafters challenge: we work with megaparsec, debug parsers, and rewrite the same things multiple times. #fp #functionalprogramming #haskell Subscribe to Impure Pics: bit.ly/impure-youtube *How to think like a functional programmer* 🎓 impurepics.thinkific.com/courses/functional-thinking *More Impure Pics* 🐣 twitter.com/impurepics 📦 impurepics.com 👕 merch.impurepics.com *Functional Alphabet book* 📗 Softcover: bit.ly/fp-abc-soft-cover 📘 Hardcover: bit.ly/fp-abc-hard-cover *Watch more Impure Pics* youtube.com/watch?v=c7FncTzvpUQ&list=UULF9-egQYdpElHtvVM-t9q… *About Impure Pics* FP Advocat. Distilling functional programming for the good of all Get in touch: zelenya.com 0:00:00 Intro 0:00:28 Hurdle 1. Stack and GHC version 0:00:51 Match literal char, digit, alphanumeric 0:03:12 Splitting pattern, parsing, and matching 0:06:42 1st (regex) parser. Introducing megaparsec 0:15:03 2nd (matcher) parser. Parsing many characters. Some debugging 0:26:07 Start and End of string anchors. 1st attempt 0:33:48 Start and End of string anchors. 2nd attempt 0:39:13 Quantifiers. 1st attempt 0:45:06 Wildcard. Realizing that quantifiers don't work 0:46:17 Quantifiers. Debugging and refactoring 0:51:37 Quantifiers. Adding State 1:03:56 More debugging 1:10:26 Alternations 1:13:58 Recap