Alex is a tool for generating lexical analysers in Haskell, given a description of the tokens to be recognised in the form of regular expressions. It is similar to the tool lex or flex for C/C++.

Alex is part of the Haskell Platform, so if you install the platform you will automatically have a working Alex. Alex is also on Hackage. If you have the cabal-install tool (which also comes with the Haskell Platform), then you can build and install the latest version of Alex with cabal install alex To find out what the latest version of Alex is, and to download the source separately, go to Alex's HackageDB page. Alex might also be pre-packaged for your OS: Ubuntu users: packages should be available from the universe repository.

Debian GNU/Linux users: packages are available here.

RPMs for other versions of Linux can be built directly from the source, using rpmbuild -ta .

. FreeBSD/x86 users: Alex is in the ports tree, so either pkg_add -r hs-alex , or install it from the ports tree in /usr/ports/devel/hs-alex .

, or install it from the ports tree in . OpenBSD users: Alex is in the -current ports tree, you can install it from /usr/ports/devel/alex .