Contributing to Alex

Source Code Repository

Alex is hosted on GitHub. As previously discussed in `bug-reports`_, we use the built-in GitHub issue tracker for Alex. We also use GitHub pull requests for managing changes; feel free to submit them!

Repo Layout

  • src: The source code for Alex itself

  • doc: The documentation

  • examples: Various examples of using Alex

Contributor Build Instructions

Alex is built using GHC and Cabal Install (version 2.0 or later). Make sure they are already installed first.

Since Alex itself is implemented in terms of an Alex scanner, bootstrapping Alex is a bit tricky:

You need to have the build-tools alex and happy manually installed; either via your system package manager distribution, the Haskell Platform, or e.g. via (run this outside the Git repository!):

$ cabal install alex happy

which installs them into ${HOME}/.cabal/bin by default. (make sure they are in your $PATH for the next steps!)

Variant A

You can install alex simply by invoking:

$ cabal install

from inside the Git folder.

Variant B

Alternatively, you can use the Makefile which automates the steps of producing a self-contained pre-bootstrapped source distribution with pre-generated lexer/scanners:

$ make sdist
$ cabal install dist/alex-*.tar.gz

For convenience, there is also a make sdist-test target which builds the source source tarball and runs the test-suite from within the source dist.