Getting errors when using the grammar environment before \chapter{} and \begin{description}

Question

I hope you can help me.

I am using an empty grammar environment, included in the syntax package, within a file called appendix_c.tex, whose contents are as follows:

\chapter{Modified version of the grammar of VHDL}\label{short-vhdl-grammar}

\begin{grammar}
\end{grammar}

Then, in a file called acronyms.tex I inserted the following code:

\chapter{List of acronyms}

\begin{description}
\item[ASIC] Application-Specific Integrated Circuit

\item[CORBA] Common Object Request Broker Architecture

\item[DCS] Digital Communications System
\item[DSML] Domain-Specific Modeling Language
...
\end{description}

I was using acronym instead of description, but got the same problem. I get the following error every time I process the main file thesis.tex:

! LaTeX Error: Something's wrong--perhaps a missing \item.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...                                              

l.11 \begin{description}

And the contents of thesis.tex are roughly like this:

\documentclass[letterpaper, 12pt]{report}

\usepackage{acronym}
\usepackage{amssymb}
\usepackage{captcont}
\usepackage{graphicx}
\usepackage[hang]{subfigure}
\usepackage{rotating}
\usepackage[T1]{fontenc}
\usepackage[nounderscore]{syntax}

\setcounter{secnumdepth}{3}
\setcounter{tocdepth}{3}

\linespread{1.3}

% Top margin
\setlength{\voffset}{0pt}
\setlength{\topmargin}{0pt}
% Heading space
\setlength{\headheight}{13pt}
\setlength{\headsep}{30pt}
% Left side margin
\setlength{\hoffset}{0pt}
\setlength{\oddsidemargin}{0.25in}
% Text dimensions
\setlength{\textheight}{596pt}
\setlength{\textwidth}{6in}
% Page number space
\setlength{\footskip}{27.10125pt}
% Margin notes
\setlength{\marginparsep}{0pt}
\setlength{\marginparwidth}{0pt}

\pagestyle{headings}

...

\begin{document}

\maketitle

\pagenumbering{roman}

\begin{abstract}
\end{abstract}

\renewcommand{\abstractname}{Resumen}

\begin{abstract}
\end{abstract}

\renewcommand{\abstractname}{Acknowledgments}

\begin{abstract}
\end{abstract}

\tableofcontents
\listoffigures
\listoftables

\newpage
\pagenumbering{arabic}

\include{./chapter_1/chapter_1}
\include{./chapter_2/chapter_2}
\include{./chapter_3/chapter_3}
\include{./chapter_4/chapter_4}
\include{./chapter_5/chapter_5}
\include{./chapter_6/chapter_6}
\include{./chapter_7/chapter_7}

\appendix

\include{./appendix_a/appendix_a}
\include{./appendix_b/appendix_b}
\include{./appendix_c/appendix_c}
\include{./acronyms/acronyms}

\bibliographystyle{abbrv}
\bibliography{bibliography}{}

\end{document}

The problem seems to be located in the transition from appendix_c.tex and acronyms.tex. Does anybody know what is going on? I cannot even start to type any grammar because of this problem. And I tried getting rid of the acronym environment but the issue is still present.

Answer 1

Do not leave the grammar environment empty; it is built using a list, so leaving it without contents (in the presence of another list-like environment!) will trigger the error. This minimal example reproduces the error

\documentclass{article}
\usepackage{syntax}

\begin{document}

\begin{grammar}
\end{grammar}

\begin{description}
\item[a]
\end{description}

\end{document}

You can comment out the lines beginning and ending the environment:

%\begin{grammar}
%\end{grammar}

or, if for some reason you need the environment there without the actual contents, simply populate it with something it expects:

\documentclass{article}
\usepackage{syntax}

\begin{document}

\begin{grammar}
<statement> ::= <ident> ‘=’ <expr>
\end{grammar}

\begin{description}
\item[a]
\end{description}

\end{document}

you can also use something simpler such as

\begin{grammar}
\item a
\end{grammar}