ALEX(1)

okay bestie, welcome to the Alex Lexical Analyser Generator manual 🎀 (aka the alex command, and yes, it's iconic)

✨ NAME ✨

alex - the lexical analyser generator for Haskell 💖

💅 SYNOPSIS 💅

alex [OPTION]... file [OPTION]...

🦋 DESCRIPTION 🦋

So this page is a quick little intro to the alex command 🌸

This page was written for the Debian GNU/Linux distribution, ngl, because the original program doesn't come with a manual page of its own 🙈. It has docs in other formats instead, including DVI, Info and HTML, which I'll mention below 📚.

Alex is a lexical analyser generator system for Haskell 🌈 it's giving lex or flex vibes for C/C++.

Input files should be file.x, and alex spits out file.y 🧚

Caveat, bestie 💀: if you're using hbc (Chalmers Haskell), the command arguments are set up a little differently. That's because the hbc run time system grabs some flags for itself (for setting things like the heap size, etc). You can get around it by adding a single dash (-) to your command line. So with an hbc generated version of Alex, the argument structure is:

alex - [OPTION]... file [OPTION]...

🌷 OPTIONS

Alex uses the usual GNU command line style, so long options start with two dashes (--) 💁 Here's a quick summary of the options. For the full deal, check out the other docs.

• -d, --debug — tells Alex to make a lexer that prints debugging messages while it runs 🐛
• -g, --ghc — makes a lexer that's optimised for compiling with GHC 🚀 It's significantly more efficient, both in terms of the size of the compiled lexer and its runtime 🔥
• -o FILE, --outfile=FILE — picks where the output goes 🍓 By default, it's the name of the input file with the .x suffix swapped out for .hs
• -i [FILE], --info[=FILE] — makes a human-readable version of the state machine (DFA) that Alex builds from your lexer, in FILE (default: file.info where the input file is file.x) 🔍
  • heads up, the info file format is kinda basic right now and not super informative 😭
• -v, --version — prints version info to standard output, then exits successfully ✅

🗂️ FILES

Just one thing here: @DATADIR@ 📁

🔗 SEE ALSO

/usr/share/doc/alex, the Alex homepage (http://haskell.org/alex/) 🦋

🏷️ COPYRIGHT

Alex Version 3.5.4.0

Copyright (c) 1995-2003, Chris Dornan and Simon Marlow

👑 AUTHOR

This page was written by Ian Lynagh <igloo@debian.org>, based on the happy manpage, for the Debian GNU/Linux system. Anyone else is welcome to use it too 🫶

---

That's the tea, from Glasgow FP Suite, dated 2003-09-09, filed under ALEX(1)! Stay iconic, bestie 💅✨