Yacc to LaTeX

Contents

The master copy of this document is available at the following URL: http://www.alchar.org/~aedil/Projects/y2l.html.

What is y2l?

The Yacc to LaTeX utility takes (hopefully) any yacc source file, and derives an Extended Backus-Naur Form (EBNF) description from it. This EBNF is written out as LaTeX source. The output is a LaTeX "longtable" environment, that can be included in any LaTeX document, typically using an \input{} statement.

What is the purpose of y2l?

Questions about the purpose of things are so common, so here is the answer to this very frequently asked question. When designing Abyss, I found that I was continuously updating the grammar in two places. The yacc description was of course the final authority. But I made it a point to ensure that I would have decent and up-to-date documentation for the language. Which led to the first incarnation of y2l.

Then came the well known moment of truth when that first version was used to try and generate an EBNF description for someone else's grammar. That failed quite miserably because of implicit dependencies on the format of the Abyss grammar description. A new y2l was written, based around a strict yacc source file parser. It is designed to be able to turn any yacc source file into an EBNF description, yet it might choke on some Bison source files, because of large liberties the authors of Bison have taken compared to the "original" yacc. This is considered to be a "known bug" and might be solved in the future.

What about portability?

How portable is this little utility? Well, it's pretty portable in the sense that is has been written in good ol' AWK! As long as you have a machine with a sensible AWK (such as Gawk, or the one true AWK on Brian Kernighan's homepage (http://plan9.bell-labs.com/cm/cs/who/bwk), it will work.

You may have to manually update the first line of the y2l script to point to the proper AWK executable on your system. Not every system has a sensible AWK as /usr/bin/awk!

Where to download y2l?

The latest release of y2l is available here for download (http://y2l.sourceforge.net/download/y2l.tar.gz).

The PGP signature for y2l is available at http://y2l.sourceforge.net/download/y2l.tar.gz.asc. The signing key can be found at the author's homepage (http://www.alchar.org/~aedil/).

Anonymous read-only CVS access is available from SourceForge. Follow these easy steps:

How to use y2l?

The y2l manual is included in the distribution in Unix manpage format and as an HTML file. The link in this section will bring you to the most current HTML version of the y2l manual.

Last modified: Jan 19th, 2001
©1995-2001 by Aedil