minimal-megaparsec-tutorial

Welcome 👋 This is the repository accompanying the minimal megaparsec tutorial blog post from Tweag's website. It can be forked to obtain a complete setup for experimenting with the megaparsec library.

Comments and improvements welcome!

Development instructions

Install the different tools (you need to have ghcup and direnv installed) locally:

mkdir -p bin/{cabal,ghc,hls,ormolu}
# All paths below match paths in .envrc, so update both places at the same time.
# cabal and GHC's version numbers are also in .github/workflows/haskell.yml
ghcup install cabal 3.12.1.0 --isolate $(pwd)/bin/cabal
ghcup install ghc 9.10.1 --isolate $(pwd)/bin/ghc
ghcup install hls 2.9.0.1 --isolate $(pwd)/bin/hls

# Note that ormolu's version number is also in .github.workflows/lint.yml
wget https://github.com/tweag/ormolu/releases/download/0.8.0.0/ormolu-x86_64-linux.zip -O bin/ormolu/ormolu.zip
unzip bin/ormolu/ormolu.zip -d bin/ormolu/

Because there is a cabal.project file that pins the set of packages to a specific timestamp, this project is highly reproducible.

Then build:

cabal update # Only required the first time
cabal build all

To run tests:

cabal test min-mega-test

To test your code interactively, you probably want to do: cabal repl Lib