diff --git a/test/issues/643/run_test.sh b/test/issues/643/run_test.sh
new file mode 100755
index 0000000..d54116e
--- /dev/null
+++ b/test/issues/643/run_test.sh
@@ -0,0 +1 @@
+time vim -Nu test.vim
diff --git a/test/issues/643/test.tex b/test/issues/643/test.tex
new file mode 100644
index 0000000..0331ef7
--- /dev/null
+++ b/test/issues/643/test.tex
@@ -0,0 +1,1110 @@
+\documentclass[12pt]{article}
+
+\usepackage{amsmath}    % need for subequations
+\usepackage{graphicx}   % need for figures
+\usepackage{verbatim}   % useful for program listings
+\usepackage{color}      % use if color is used in text
+\usepackage{subfigure}  % use for side-by-side figures
+\usepackage{hyperref}   % use for hypertext links, including those to external documents and URLs
+
+% don't need the following. simply use defaults
+\setlength{\baselineskip}{16.0pt}    % 16 pt usual spacing between lines
+
+\setlength{\parskip}{3pt plus 2pt}
+\setlength{\parindent}{20pt}
+\setlength{\oddsidemargin}{0.5cm}
+\setlength{\evensidemargin}{0.5cm}
+\setlength{\marginparsep}{0.75cm}
+\setlength{\marginparwidth}{2.5cm}
+\setlength{\marginparpush}{1.0cm}
+\setlength{\textwidth}{150mm}
+
+\begin{comment}
+  \pagestyle{empty} % use if page numbers not wanted
+\end{comment}
+
+% above is the preamble
+
+\begin{document}
+
+\begin{center}
+  {\large Introduction to \LaTeX} \\ % \\ = new line
+  \copyright 2006 by Harvey Gould \\
+  December 5, 2006
+\end{center}
+
+\section{Introduction}
+\TeX\ looks more difficult than it is. It is
+almost as easy as $\pi$. See how easy it is to make special
+symbols such as $\alpha$,
+$\beta$, $\gamma$,
+$\delta$, $\sin x$, $\hbar$, $\lambda$, $\ldots$ We also can make
+subscripts
+$A_{x}$, $A_{xy}$ and superscripts, $e^x$, $e^{x^2}$, and
+$e^{a^b}$. We will use \LaTeX, which is based on \TeX\ and has
+many higher-level commands (macros) for formatting, making
+tables, etc. More information can be found in Ref.~\cite{latex}.
+
+We just made a new paragraph. Extra lines and spaces make no
+difference. Note that all formulas are enclosed by
+\$ and occur in \textit{math mode}.
+
+The default font is Computer Modern. It includes \textit{italics},
+\textbf{boldface},
+\textsl{slanted}, and \texttt{monospaced} fonts.
+
+\section{Equations}
+Let us see how easy it is to write equations.
+\begin{equation}
+  \Delta =\sum_{i=1}^N w_i (x_i - \bar{x})^2 .
+\end{equation}
+It is a good idea to number equations, but we can have a
+equation without a number by writing
+\begin{equation}
+  P(x) = \frac{x - a}{b - a} , \nonumber
+\end{equation}
+and
+\begin{equation}
+  g = \frac{1}{2} \sqrt{2\pi} . \nonumber
+\end{equation}
+
+We can give an equation a label so that we can refer to it later.
+\begin{equation}
+  \label{eq:ising}
+  E = -J \sum_{i=1}^N s_i s_{i+1} ,
+\end{equation}
+Equation~\eqref{eq:ising} expresses the energy of a configuration
+of spins in the Ising model.\footnote{It is necessary to process (typeset) a
+file twice to get the counters correct.}
+
+We can define our own macros to save typing. For example, suppose
+that we introduce the macros:
+\begin{verbatim}
+ \newcommand{\lb}{{\langle}}
+ \newcommand{\rb}{{\rangle}}
+\end{verbatim}
+\newcommand{\lb}{{\langle}}
+\newcommand{\rb}{{\rangle}}
+Then we can write the average value of $x$ as
+\begin{verbatim}
+\begin{equation}
+\lb x \rb = 3
+\end{equation}
+\end{verbatim}
+The result is
+\begin{equation}
+  \lb x \rb = 3 .
+\end{equation}
+
+Examples of more complicated equations:
+\begin{equation}
+  I = \! \int_{-\infty}^\infty f(x)\,dx \label{eq:fine}.
+\end{equation}
+We can do some fine tuning by adding small amounts of horizontal
+spacing:
+\begin{verbatim}
+ \, small space       \! negative space
+\end{verbatim}
+as is done in Eq.~\eqref{eq:fine}.
+
+We also can align several equations:
+\begin{align}
+  a & = b \\
+  c &= d ,
+\end{align}
+or number them as subequations:
+\begin{subequations}
+  \begin{align}
+    a & = b \\
+    c &= d .
+  \end{align}
+\end{subequations}
+
+We can also have different cases:
+\begin{equation}
+  \label{eq:mdiv}
+  m(T) =
+  \begin{cases}
+  0 & \text{$T > T_c$} \\
+\bigl(1 - [\sinh 2 \beta J]^{-4} \bigr)^{\! 1/8} & \text{$T < T_c$}
+\end{cases}
+\end{equation}
+write matrices
+\begin{align}
+  \textbf{T} &=
+  \begin{pmatrix}
+    T_{++} \hfill & T_{+-} \\
+    T_{-+} & T_{--} \hfill 
+  \end{pmatrix} , \nonumber \\
+  & =
+  \begin{pmatrix}
+    e^{\beta (J + B)} \hfill & e^{-\beta J} \hfill \\
+    e^{-\beta J} \hfill & e^{\beta (J - B)} \hfill
+  \end{pmatrix}.
+\end{align}
+and 
+\newcommand{\rv}{\textbf{r}}
+\begin{equation}
+  \sum_i \vec A \cdot \vec B = -P\!\int\! \rv \cdot
+  \hat{\mathbf{n}}\, dA = P\!\int \! {\vec \nabla} \cdot \rv\, dV.
+\end{equation}
+
+\section{Tables}
+Tables are a little more difficult. TeX
+automatically calculates the width of the columns.
+
+\begin{table}[h]
+  \begin{center}
+    \begin{tabular}{|l|l|r|l|}
+      \hline
+      lattice & $d$ & $q$ & $T_{\rm mf}/T_c$ \\
+      \hline
+      square & 2 & 4 & 1.763 \\
+      \hline
+      triangular & 2 & 6 & 1.648 \\
+      \hline
+      diamond & 3 & 4 & 1.479 \\
+      \hline
+      simple cubic & 3 & 6 & 1.330 \\
+      \hline
+      bcc & 3 & 8 & 1.260 \\
+      \hline
+      fcc & 3 & 12 & 1.225 \\
+      \hline
+    \end{tabular}
+    \caption{\label{tab:5/tc}Comparison of the mean-field predictions
+      for the critical temperature of the Ising model with exact results
+      and the best known estimates for different spatial dimensions $d$
+    and lattice symmetries.}
+  \end{center}
+\end{table}
+
+\section{Lists}
+
+Some example of formatted lists include the
+following:
+
+\begin{enumerate}
+
+  \item bread
+
+  \item cheese
+
+\end{enumerate}
+
+\begin{itemize}
+
+  \item Tom
+
+  \item Dick
+
+\end{itemize}
+
+\section{Figures}
+
+We can make figures bigger or smaller by scaling them. Figure~\ref{fig:lj}
+has been scaled by 60\%.
+
+\begin{figure}[h]
+  \begin{center}
+    \includegraphics{figures/sine}
+    \caption{\label{fig:typical}Show me a sine.}
+  \end{center}
+\end{figure}
+
+\begin{figure}[h]
+  \begin{center}
+    \scalebox{0.6}{\includegraphics{figures/lj}}
+    \caption{\label{fig:lj}Plot of the
+      Lennard-Jones potential
+      $u(r)$. The potential is characterized by a length
+      $\sigma$ and an energy
+    $\epsilon$.}
+  \end{center}
+\end{figure}
+
+\section{Literal text}
+It is desirable to print program code exactly as it is typed in a
+monospaced font. Use \verb \begin{verbatim} and
+\verb \end{verbatim} as in the following example:
+\begin{verbatim}
+double y0 = 10; // example of declaration and assignment statement
+double v0 = 0;  // initial velocity
+double t = 0;   // time
+double dt = 0.01; // time step
+double y = y0;
+\end{verbatim}
+The command \verb \verbatiminput{programs/Square.java}\ allows
+you to list the file \texttt{Square.java} in the directory
+programs.
+
+\section{Special Symbols}
+
+\subsection{Common Greek letters}
+
+These commands may be used only in math mode. Only the most common
+letters are included here.
+
+$\alpha, 
+\beta, \gamma, \Gamma,
+\delta,\Delta,
+\epsilon, \zeta, \eta, \theta, \Theta, \kappa,
+\lambda, \Lambda, \mu, \nu,
+\xi, \Xi,
+\pi, \Pi,
+\rho,
+\sigma, 
+\tau,
+\phi, \Phi,
+\chi,
+\psi, \Psi,
+\omega, \Omega$
+
+\subsection{Special symbols}
+
+The derivative is defined as
+\begin{equation}
+  \frac{dy}{dx} = \lim_{\Delta x \to 0} \frac{\Delta y}
+  {\Delta x}
+\end{equation}
+\begin{equation}
+  f(x) \to y \quad \mbox{as} \quad x \to
+  x_{0}
+\end{equation}
+\begin{equation}
+  f(x) \mathop {\longrightarrow}
+  \limits_{x \to x_0} y
+\end{equation}
+
+\noindent Order of magnitude:
+\begin{equation}
+  \log_{10}f \simeq n
+\end{equation}
+\begin{equation}
+  f(x)\sim 10^{n}
+\end{equation}
+Approximate equality:
+\begin{equation}
+  f(x)\simeq g(x)
+\end{equation}
+\LaTeX\ is simple if we keep everything in proportion:
+\begin{equation}
+  f(x) \propto x^3 .
+\end{equation}
+
+Finally we can skip some space by using commands such as
+\begin{verbatim}
+\bigskip    \medskip    \smallskip    \vspace{1pc}
+\end{verbatim}
+The space can be negative.
+
+\section{\color{red}Use of Color}
+
+{\color{blue}{We can change colors for emphasis}},
+{\color{green}{but}} {\color{cyan}{who is going pay for the ink?}}
+
+\section{\label{morefig}Subfigures}
+
+As soon as many students start becoming comfortable using \LaTeX, they want
+to use some of its advanced features. So we now show how to place two
+figures side by side.
+
+\begin{figure}[h!]
+  \begin{center}
+    \subfigure[Real and imaginary.]{
+    \includegraphics[scale=0.5]{figures/reim}}
+    \subfigure[Amplitude and phase.]{
+    \includegraphics[scale=0.5]{figures/phase}}
+    \caption{\label{fig:qm/complexfunctions} Two representations of complex
+    wave functions.}
+  \end{center}
+\end{figure}
+
+We first have to include the necessary package,
+\verb+\usepackage{subfigure}+, which has to go in the preamble (before
+\verb+\begin{document}+). It sometimes can be difficult to place a figure in
+the desired place.
+
+Your LaTeX document can be easily modified to make a poster or a screen
+presentation similar to (and better than) PowerPoint. Conversion to HTML is
+straightforward. Comments on this tutorial are appreciated.
+
+\begin{thebibliography}{5}
+
+  \bibitem{latex}Helmut Kopka and Patrick W. Daly, \textsl{A Guide to
+  \LaTeX: Document Preparation for Beginners and Advanced Users},
+  fourth edition, Addison-Wesley (2004).
+
+  \bibitem{website}Some useful links are
+  given at \url{}.
+
+\end{thebibliography}
+
+{\small \noindent Updated 5 December 2006.}
+\section{Introduction}
+
+\latex is a typesetting program; given an input file with formatting
+instructions (e.g intro.tex), the program will create your document in
+one of several formats (DVI, Postscript or PDF).  It is therefore not
+a WYSIWYG word processor.  \latex is known as a logical markup
+language, similar for example to HTML, so that you describe a piece of
+text as a ``section heading'' rather than saying that it should be
+formatted in a certain way.  It has excellent facilities for
+typesetting mathematics, and handles large documents (such as theses)
+well.  The aim of this document is not to provide an overview of
+\latex, since many other guides have already been written (see
+Section~\ref{sec:summary}).  Instead, it has been written primarily to
+provide simple workable examples that you can cut and paste to help
+you get started with \latex.  The examples have been selected to be
+those most likely to be useful when writing a scientific report.  This
+document is best read by comparing the source code with the resulting
+output.
+
+\section{Running \latex}
+
+The files to accompany this paper are at:
+\url{http://www.damtp.cam.ac.uk/user/eglen/texintro}.  Get the
+following files and put them into a new directory.
+
+\begin{enumerate}
+  \item \url{intro.tex}: the main \latex document.
+  \item \url{example.bib}: a short bibliography.
+  \item \url{sigmoid.ps}: example postscript image.
+  \item \url{sigmoid.pdf}: example PDF image.
+\end{enumerate}
+
+Change directory to where you stored the files and type the
+following (ignoring comments placed after \#\#):
+
+\begin{verbatim}
+latex intro                     ## Run latex 1st time.
+bibtex intro                    ## Extract required references
+latex intro                     ## Run latex 2nd to resolve references.
+latex intro                     ## Probably need to run latex a 3rd time.
+xdvi intro                      ## View the DVI (device independent) file.
+dvips -o intro.ps intro         ## Create a postscript file for printing.
+\end{verbatim}
+
+You will notice that you run latex several times here; this is so that
+references can be resolved, and references can be extracted from your
+bibtex file.  After running latex, you will be told if you need to run
+it again to resolve references.  After a while, you will get the idea
+of how many times you need to run latex to resolve all your
+references.
+
+If instead you would like to generate PDF files (see
+Section~\ref{sec:graphics} for a discussion of file formats for
+included images), you can try the following shorter sequence:
+
+\begin{verbatim}
+pdflatex intro
+bibtex intro
+pdflatex intro
+pdflatex intro
+xpdf intro.pdf                  ## View the resulting PDF
+\end{verbatim}
+
+Whether you prefer to generate DVI or PDF is up to you.  The xdvi
+viewer has some nice features, such as it can reload your document
+easily and has a ``magnifying glass'' that is activated by the mouse.
+On the other hand, xpdf will display the document more accurately as 
+it will be printed.
+
+\section{Tables}
+
+Tables are relatively straightforward to generate.  Note that tables
+and figures are not always placed exactly where you wish, as
+they can \textit{float} to other parts of the document.  Rather than
+trying to battle with \latex as to where they are placed, concentrate
+first on getting the right content and let \latex worry about the
+positioning.  Instead, use labels to your tables to refer to them.
+See Table~\ref{tab:simple} and Table~\ref{tab:pars} for examples.
+
+\begin{table}
+  \centering
+  \begin{tabular}{ccc}
+    year & min temp (\textdegree C) & max temp (\textdegree C)\\ 
+    \hline
+    1970 & $-5$ & 35\\
+    1975 & $-7$ & 29\\
+    1980 & $-3$ & 30\\
+    1985 & $-2$ & 32\\
+  \end{tabular}
+  \caption{Fictional minimal and maximal temperatures recorded in
+  Cambridge over several years.}
+  \label{tab:simple}
+\end{table}
+%% Why are the negative numbers above enclosed in math mode?
+%% Hint: consider the difference between "-" in text and in math.
+
+\begin{table}[htbp]
+  \centering
+  \begin{tabular}{lccc}\\ \hline
+    & \multicolumn{1}{c}{$\phi$ (\micro m)}
+    & \multicolumn{1}{c}{$\alpha$}
+    & $\delta_{12}$ (\micro m)\\ \hline
+    W81S1\\
+    $h_{11}(u)$  & 67.94 & 7.81\\
+    $h_{22}(u)$  & 66.27 & 5.40\\
+    $h_{12}(u)$  &       &     &18\\
+    \hline
+    M623\\
+    $h_{11}(u)$  &112.79 &  3.05\\
+    $h_{22}(u)$  & 65.46 &  8.11\\
+    $h_{12}(u)$  &       &      &20\\
+    \hline
+  \end{tabular}
+  \caption{Summary of parameter estimates for the univariate
+    functions $h_{11}(u)$, $h_{22}(u)$ and the bivariate function
+    $h_{12}(u)$.  For the univariate fits, $\alpha$ and $\phi$ are 
+    least-square estimates (assuming $\delta$ was fixed at 15 \micro m).
+    The final column gives the
+    maximum likelihood estimate of $\delta_{12}$ assuming that the
+    interaction between types is simple inhibition.
+  \label{tab:pars}}
+\end{table}
+
+
+\section{Bibliography management}
+
+Scientific reports normally require a section where your references
+are listed.  Bibtex is an excellent system for maintaining references,
+especially for large documents.  Each reference needs a unique key;
+you can then refer to the reference in your \latex document by using
+this key within a cite command.
+
+Take care when formatting your references, especially when it comes to
+writing authors names and the case of letters in journal titles.  In
+our examples, the files are found in \url{example.bib}.  As an example
+of a citation, see \citep{ihaka1996} or \citep{ihaka1996,venables1999}.
+
+Bibtex is flexible enough to format your references in a wide number
+of different styles to suit your needs.  In this file I have used the
+``natbib'' package, which is suitable for the natural sciences.
+Depending on the type of cite command you get (and the package that
+you use for citations), you can get different styles of citation.  See
+Table~\ref{tab:cite} for some examples.
+
+\begin{table}
+  \centering
+  \begin{tabular}{ll}
+    \hline
+    command & result\\ \hline
+    \verb+\citep{ihaka1996}+ & \citep{ihaka1996}\\
+    \verb+\citet{ihaka1996}+ & \citet{ihaka1996}\\
+    \verb+\citep[see][p. 300]{ihaka1996}+ &
+    \citep[see][p. 300]{ihaka1996}
+    \\
+    \verb+\citeauthor{ihaka1996}+ & \citeauthor{ihaka1996}
+    \\
+    \verb+\citeyear{ihaka1996}+ & \citeyear{ihaka1996}
+    \\
+    \hline
+  \end{tabular}
+  \caption{Examples of different citation commands available in the
+  natbib package.}
+  \label{tab:cite}
+\end{table}
+
+
+\section{Graphics}
+\label{sec:graphics}
+
+\latex can include images in one of several format, depending on
+whether you use latex (postscript format required) or pdflatex (either
+jpeg, png or pdf required).  Figures can be included either at their
+natural size, or you can specify e.g. the figure width.
+Figure~\ref{fig:example} shows an example image which intentionally
+looks slightly different depending on whether you compile the document
+with latex or pdflatex.  Note that in this example the suffix of the
+image file is not included so that this document compiles under both
+latex and pdflatex.
+
+\begin{figure}
+  \centering
+  \includegraphics[width=6cm]{sigmoid}
+  \caption{Example of a sigmoidal curve generated by the R programming
+    environment.  The title above the curve indicates whether you have
+  included the postscript or the pdf version of the figure.}
+  \label{fig:example}
+\end{figure}
+
+\section{Mathematics}
+
+\latex can format mathematics with ease, either in line, such as 
+$x \times y$, or on separate lines, such as:
+\[ x^2 +y^2 = z^2 \]
+
+If you are writing several lines of equations, you can use statements
+like the following:
+
+\begin{align}
+  b(t) & = s(t) - \int_{0}^{T} a(t') \cdot i(T-t') dt'
+  \\
+  a(t) & = \int_{0}^{T} b(t) \cdot e(T-t') dt' \label{eq:am}
+  \\
+  g(t) & = b(t) \ast e(t) \nonumber
+\end{align}
+
+By using labels on certain equations, we can refer to equations by
+number, such as equation~(\ref{eq:am}).
+
+\section{Summary}
+\label{sec:summary}
+This short guide should give you a flavour of what can be done with
+\latex.  It is by no means complete, or supposed to be
+self-explanatory.  It is, however, hopefully enough to get you
+started!  Try experimenting by editing the source file and then
+recompiling this document.  As mentioned earlier, there are many
+guides for latex.  Two that I can recommend are
+\url{http://www.andy-roberts.net/misc/latex/index.html} and 
+`` The (Not So) Short Introduction to LaTeX2e''
+(\url{http://ctan.tug.org/tex-archive/info/lshort/english/lshort.pdf}).
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Finally we specify the format required for our references and the
+%% name of the bibtex file where our references should be taken from.
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+\bibliographystyle{plainnat}
+\bibliography{example}
+
+\section{Introduction}
+\TeX\ looks more difficult than it is. It is
+almost as easy as $\pi$. See how easy it is to make special
+symbols such as $\alpha$,
+$\beta$, $\gamma$,
+$\delta$, $\sin x$, $\hbar$, $\lambda$, $\ldots$ We also can make
+subscripts
+$A_{x}$, $A_{xy}$ and superscripts, $e^x$, $e^{x^2}$, and
+$e^{a^b}$. We will use \LaTeX, which is based on \TeX\ and has
+many higher-level commands (macros) for formatting, making
+tables, etc. More information can be found in Ref.~\cite{latex}.
+
+We just made a new paragraph. Extra lines and spaces make no
+difference. Note that all formulas are enclosed by
+\$ and occur in \textit{math mode}.
+
+The default font is Computer Modern. It includes \textit{italics},
+\textbf{boldface},
+\textsl{slanted}, and \texttt{monospaced} fonts.
+
+\section{Equations}
+Let us see how easy it is to write equations.
+\begin{equation}
+  \Delta =\sum_{i=1}^N w_i (x_i - \bar{x})^2 .
+\end{equation}
+It is a good idea to number equations, but we can have a
+equation without a number by writing
+\begin{equation}
+  P(x) = \frac{x - a}{b - a} , \nonumber
+\end{equation}
+and
+\begin{equation}
+  g = \frac{1}{2} \sqrt{2\pi} . \nonumber
+\end{equation}
+
+We can give an equation a label so that we can refer to it later.
+\begin{equation}
+  \label{eq:ising}
+  E = -J \sum_{i=1}^N s_i s_{i+1} ,
+\end{equation}
+Equation~\eqref{eq:ising} expresses the energy of a configuration
+of spins in the Ising model.\footnote{It is necessary to process (typeset) a
+file twice to get the counters correct.}
+
+We can define our own macros to save typing. For example, suppose
+that we introduce the macros:
+\begin{verbatim}
+ \newcommand{\lb}{{\langle}}
+ \newcommand{\rb}{{\rangle}}
+\end{verbatim}
+\newcommand{\lb}{{\langle}}
+\newcommand{\rb}{{\rangle}}
+Then we can write the average value of $x$ as
+\begin{verbatim}
+\begin{equation}
+\lb x \rb = 3
+\end{equation}
+\end{verbatim}
+The result is
+\begin{equation}
+  \lb x \rb = 3 .
+\end{equation}
+
+Examples of more complicated equations:
+\begin{equation}
+  I = \! \int_{-\infty}^\infty f(x)\,dx \label{eq:fine}.
+\end{equation}
+We can do some fine tuning by adding small amounts of horizontal
+spacing:
+\begin{verbatim}
+ \, small space       \! negative space
+\end{verbatim}
+as is done in Eq.~\eqref{eq:fine}.
+
+We also can align several equations:
+\begin{align}
+  a & = b \\
+  c &= d ,
+\end{align}
+or number them as subequations:
+\begin{subequations}
+  \begin{align}
+    a & = b \\
+    c &= d .
+  \end{align}
+\end{subequations}
+
+We can also have different cases:
+\begin{equation}
+  \label{eq:mdiv}
+  m(T) =
+  \begin{cases}
+  0 & \text{$T > T_c$} \\
+\bigl(1 - [\sinh 2 \beta J]^{-4} \bigr)^{\! 1/8} & \text{$T < T_c$}
+\end{cases}
+\end{equation}
+write matrices
+\begin{align}
+  \textbf{T} &=
+  \begin{pmatrix}
+    T_{++} \hfill & T_{+-} \\
+    T_{-+} & T_{--} \hfill 
+  \end{pmatrix} , \nonumber \\
+  & =
+  \begin{pmatrix}
+    e^{\beta (J + B)} \hfill & e^{-\beta J} \hfill \\
+    e^{-\beta J} \hfill & e^{\beta (J - B)} \hfill
+  \end{pmatrix}.
+\end{align}
+and 
+\newcommand{\rv}{\textbf{r}}
+\begin{equation}
+  \sum_i \vec A \cdot \vec B = -P\!\int\! \rv \cdot
+  \hat{\mathbf{n}}\, dA = P\!\int \! {\vec \nabla} \cdot \rv\, dV.
+\end{equation}
+
+\section{Tables}
+Tables are a little more difficult. TeX
+automatically calculates the width of the columns.
+
+\begin{table}[h]
+  \begin{center}
+    \begin{tabular}{|l|l|r|l|}
+      \hline
+      lattice & $d$ & $q$ & $T_{\rm mf}/T_c$ \\
+      \hline
+      square & 2 & 4 & 1.763 \\
+      \hline
+      triangular & 2 & 6 & 1.648 \\
+      \hline
+      diamond & 3 & 4 & 1.479 \\
+      \hline
+      simple cubic & 3 & 6 & 1.330 \\
+      \hline
+      bcc & 3 & 8 & 1.260 \\
+      \hline
+      fcc & 3 & 12 & 1.225 \\
+      \hline
+    \end{tabular}
+    \caption{\label{tab:5/tc}Comparison of the mean-field predictions
+      for the critical temperature of the Ising model with exact results
+      and the best known estimates for different spatial dimensions $d$
+    and lattice symmetries.}
+  \end{center}
+\end{table}
+
+\section{Lists}
+
+Some example of formatted lists include the
+following:
+
+\begin{enumerate}
+
+  \item bread
+
+  \item cheese
+
+\end{enumerate}
+
+\begin{itemize}
+
+  \item Tom
+
+  \item Dick
+
+\end{itemize}
+
+\section{Figures}
+
+We can make figures bigger or smaller by scaling them. Figure~\ref{fig:lj}
+has been scaled by 60\%.
+
+\begin{figure}[h]
+  \begin{center}
+    \includegraphics{figures/sine}
+    \caption{\label{fig:typical}Show me a sine.}
+  \end{center}
+\end{figure}
+
+\begin{figure}[h]
+  \begin{center}
+    \scalebox{0.6}{\includegraphics{figures/lj}}
+    \caption{\label{fig:lj}Plot of the
+      Lennard-Jones potential
+      $u(r)$. The potential is characterized by a length
+      $\sigma$ and an energy
+    $\epsilon$.}
+  \end{center}
+\end{figure}
+
+\section{Literal text}
+It is desirable to print program code exactly as it is typed in a
+monospaced font. Use \verb \begin{verbatim} and
+\verb \end{verbatim} as in the following example:
+\begin{verbatim}
+double y0 = 10; // example of declaration and assignment statement
+double v0 = 0;  // initial velocity
+double t = 0;   // time
+double dt = 0.01; // time step
+double y = y0;
+\end{verbatim}
+The command \verb \verbatiminput{programs/Square.java}\ allows
+you to list the file \texttt{Square.java} in the directory
+programs.
+
+\section{Special Symbols}
+
+\subsection{Common Greek letters}
+
+These commands may be used only in math mode. Only the most common
+letters are included here.
+
+$\alpha, 
+\beta, \gamma, \Gamma,
+\delta,\Delta,
+\epsilon, \zeta, \eta, \theta, \Theta, \kappa,
+\lambda, \Lambda, \mu, \nu,
+\xi, \Xi,
+\pi, \Pi,
+\rho,
+\sigma, 
+\tau,
+\phi, \Phi,
+\chi,
+\psi, \Psi,
+\omega, \Omega$
+
+\subsection{Special symbols}
+
+The derivative is defined as
+\begin{equation}
+  \frac{dy}{dx} = \lim_{\Delta x \to 0} \frac{\Delta y}
+  {\Delta x}
+\end{equation}
+\begin{equation}
+  f(x) \to y \quad \mbox{as} \quad x \to
+  x_{0}
+\end{equation}
+\begin{equation}
+  f(x) \mathop {\longrightarrow}
+  \limits_{x \to x_0} y
+\end{equation}
+
+\noindent Order of magnitude:
+\begin{equation}
+  \log_{10}f \simeq n
+\end{equation}
+\begin{equation}
+  f(x)\sim 10^{n}
+\end{equation}
+Approximate equality:
+\begin{equation}
+  f(x)\simeq g(x)
+\end{equation}
+\LaTeX\ is simple if we keep everything in proportion:
+\begin{equation}
+  f(x) \propto x^3 .
+\end{equation}
+
+Finally we can skip some space by using commands such as
+\begin{verbatim}
+\bigskip    \medskip    \smallskip    \vspace{1pc}
+\end{verbatim}
+The space can be negative.
+
+\section{\color{red}Use of Color}
+
+{\color{blue}{We can change colors for emphasis}},
+{\color{green}{but}} {\color{cyan}{who is going pay for the ink?}}
+
+\section{\label{morefig}Subfigures}
+
+As soon as many students start becoming comfortable using \LaTeX, they want
+to use some of its advanced features. So we now show how to place two
+figures side by side.
+
+\begin{figure}[h!]
+  \begin{center}
+    \subfigure[Real and imaginary.]{
+    \includegraphics[scale=0.5]{figures/reim}}
+    \subfigure[Amplitude and phase.]{
+    \includegraphics[scale=0.5]{figures/phase}}
+    \caption{\label{fig:qm/complexfunctions} Two representations of complex
+    wave functions.}
+  \end{center}
+\end{figure}
+
+We first have to include the necessary package,
+\verb+\usepackage{subfigure}+, which has to go in the preamble (before
+\verb+\begin{document}+). It sometimes can be difficult to place a figure in
+the desired place.
+
+Your LaTeX document can be easily modified to make a poster or a screen
+presentation similar to (and better than) PowerPoint. Conversion to HTML is
+straightforward. Comments on this tutorial are appreciated.
+
+\begin{thebibliography}{5}
+
+  \bibitem{latex}Helmut Kopka and Patrick W. Daly, \textsl{A Guide to
+  \LaTeX: Document Preparation for Beginners and Advanced Users},
+  fourth edition, Addison-Wesley (2004).
+
+  \bibitem{website}Some useful links are
+  given at \url{}.
+
+\end{thebibliography}
+
+{\small \noindent Updated 5 December 2006.}
+\section{Introduction}
+
+\latex is a typesetting program; given an input file with formatting
+instructions (e.g intro.tex), the program will create your document in
+one of several formats (DVI, Postscript or PDF).  It is therefore not
+a WYSIWYG word processor.  \latex is known as a logical markup
+language, similar for example to HTML, so that you describe a piece of
+text as a ``section heading'' rather than saying that it should be
+formatted in a certain way.  It has excellent facilities for
+typesetting mathematics, and handles large documents (such as theses)
+well.  The aim of this document is not to provide an overview of
+\latex, since many other guides have already been written (see
+Section~\ref{sec:summary}).  Instead, it has been written primarily to
+provide simple workable examples that you can cut and paste to help
+you get started with \latex.  The examples have been selected to be
+those most likely to be useful when writing a scientific report.  This
+document is best read by comparing the source code with the resulting
+output.
+
+\section{Running \latex}
+
+The files to accompany this paper are at:
+\url{http://www.damtp.cam.ac.uk/user/eglen/texintro}.  Get the
+following files and put them into a new directory.
+
+\begin{enumerate}
+  \item \url{intro.tex}: the main \latex document.
+  \item \url{example.bib}: a short bibliography.
+  \item \url{sigmoid.ps}: example postscript image.
+  \item \url{sigmoid.pdf}: example PDF image.
+\end{enumerate}
+
+Change directory to where you stored the files and type the
+following (ignoring comments placed after \#\#):
+
+\begin{verbatim}
+latex intro                     ## Run latex 1st time.
+bibtex intro                    ## Extract required references
+latex intro                     ## Run latex 2nd to resolve references.
+latex intro                     ## Probably need to run latex a 3rd time.
+xdvi intro                      ## View the DVI (device independent) file.
+dvips -o intro.ps intro         ## Create a postscript file for printing.
+\end{verbatim}
+
+You will notice that you run latex several times here; this is so that
+references can be resolved, and references can be extracted from your
+bibtex file.  After running latex, you will be told if you need to run
+it again to resolve references.  After a while, you will get the idea
+of how many times you need to run latex to resolve all your
+references.
+
+If instead you would like to generate PDF files (see
+Section~\ref{sec:graphics} for a discussion of file formats for
+included images), you can try the following shorter sequence:
+
+\begin{verbatim}
+pdflatex intro
+bibtex intro
+pdflatex intro
+pdflatex intro
+xpdf intro.pdf                  ## View the resulting PDF
+\end{verbatim}
+
+Whether you prefer to generate DVI or PDF is up to you.  The xdvi
+viewer has some nice features, such as it can reload your document
+easily and has a ``magnifying glass'' that is activated by the mouse.
+On the other hand, xpdf will display the document more accurately as 
+it will be printed.
+
+\section{Tables}
+
+Tables are relatively straightforward to generate.  Note that tables
+and figures are not always placed exactly where you wish, as
+they can \textit{float} to other parts of the document.  Rather than
+trying to battle with \latex as to where they are placed, concentrate
+first on getting the right content and let \latex worry about the
+positioning.  Instead, use labels to your tables to refer to them.
+See Table~\ref{tab:simple} and Table~\ref{tab:pars} for examples.
+
+\begin{table}
+  \centering
+  \begin{tabular}{ccc}
+    year & min temp (\textdegree C) & max temp (\textdegree C)\\ 
+    \hline
+    1970 & $-5$ & 35\\
+    1975 & $-7$ & 29\\
+    1980 & $-3$ & 30\\
+    1985 & $-2$ & 32\\
+  \end{tabular}
+  \caption{Fictional minimal and maximal temperatures recorded in
+  Cambridge over several years.}
+  \label{tab:simple}
+\end{table}
+%% Why are the negative numbers above enclosed in math mode?
+%% Hint: consider the difference between "-" in text and in math.
+
+\begin{table}[htbp]
+  \centering
+  \begin{tabular}{lccc}\\ \hline
+    & \multicolumn{1}{c}{$\phi$ (\micro m)}
+    & \multicolumn{1}{c}{$\alpha$}
+    & $\delta_{12}$ (\micro m)\\ \hline
+    W81S1\\
+    $h_{11}(u)$  & 67.94 & 7.81\\
+    $h_{22}(u)$  & 66.27 & 5.40\\
+    $h_{12}(u)$  &       &     &18\\
+    \hline
+    M623\\
+    $h_{11}(u)$  &112.79 &  3.05\\
+    $h_{22}(u)$  & 65.46 &  8.11\\
+    $h_{12}(u)$  &       &      &20\\
+    \hline
+  \end{tabular}
+  \caption{Summary of parameter estimates for the univariate
+    functions $h_{11}(u)$, $h_{22}(u)$ and the bivariate function
+    $h_{12}(u)$.  For the univariate fits, $\alpha$ and $\phi$ are 
+    least-square estimates (assuming $\delta$ was fixed at 15 \micro m).
+    The final column gives the
+    maximum likelihood estimate of $\delta_{12}$ assuming that the
+    interaction between types is simple inhibition.
+  \label{tab:pars}}
+\end{table}
+
+
+\section{Bibliography management}
+
+Scientific reports normally require a section where your references
+are listed.  Bibtex is an excellent system for maintaining references,
+especially for large documents.  Each reference needs a unique key;
+you can then refer to the reference in your \latex document by using
+this key within a cite command.
+
+Take care when formatting your references, especially when it comes to
+writing authors names and the case of letters in journal titles.  In
+our examples, the files are found in \url{example.bib}.  As an example
+of a citation, see \citep{ihaka1996} or \citep{ihaka1996,venables1999}.
+
+Bibtex is flexible enough to format your references in a wide number
+of different styles to suit your needs.  In this file I have used the
+``natbib'' package, which is suitable for the natural sciences.
+Depending on the type of cite command you get (and the package that
+you use for citations), you can get different styles of citation.  See
+Table~\ref{tab:cite} for some examples.
+
+\begin{table}
+  \centering
+  \begin{tabular}{ll}
+    \hline
+    command & result\\ \hline
+    \verb+\citep{ihaka1996}+ & \citep{ihaka1996}\\
+    \verb+\citet{ihaka1996}+ & \citet{ihaka1996}\\
+    \verb+\citep[see][p. 300]{ihaka1996}+ &
+    \citep[see][p. 300]{ihaka1996}
+    \\
+    \verb+\citeauthor{ihaka1996}+ & \citeauthor{ihaka1996}
+    \\
+    \verb+\citeyear{ihaka1996}+ & \citeyear{ihaka1996}
+    \\
+    \hline
+  \end{tabular}
+  \caption{Examples of different citation commands available in the
+  natbib package.}
+  \label{tab:cite}
+\end{table}
+
+
+\section{Graphics}
+\label{sec:graphics}
+
+\latex can include images in one of several format, depending on
+whether you use latex (postscript format required) or pdflatex (either
+jpeg, png or pdf required).  Figures can be included either at their
+natural size, or you can specify e.g. the figure width.
+Figure~\ref{fig:example} shows an example image which intentionally
+looks slightly different depending on whether you compile the document
+with latex or pdflatex.  Note that in this example the suffix of the
+image file is not included so that this document compiles under both
+latex and pdflatex.
+
+\begin{figure}
+  \centering
+  \includegraphics[width=6cm]{sigmoid}
+  \caption{Example of a sigmoidal curve generated by the R programming
+    environment.  The title above the curve indicates whether you have
+  included the postscript or the pdf version of the figure.}
+  \label{fig:example}
+\end{figure}
+
+\section{Mathematics}
+
+\latex can format mathematics with ease, either in line, such as 
+$x \times y$, or on separate lines, such as:
+\[ x^2 +y^2 = z^2 \]
+
+If you are writing several lines of equations, you can use statements
+like the following:
+
+\begin{align}
+  b(t) & = s(t) - \int_{0}^{T} a(t') \cdot i(T-t') dt'
+  \\
+  a(t) & = \int_{0}^{T} b(t) \cdot e(T-t') dt' \label{eq:am}
+  \\
+  g(t) & = b(t) \ast e(t) \nonumber
+\end{align}
+
+By using labels on certain equations, we can refer to equations by
+number, such as equation~(\ref{eq:am}).
+
+\section{Summary}
+\label{sec:summary}
+This short guide should give you a flavour of what can be done with
+\latex.  It is by no means complete, or supposed to be
+self-explanatory.  It is, however, hopefully enough to get you
+started!  Try experimenting by editing the source file and then
+recompiling this document.  As mentioned earlier, there are many
+guides for latex.  Two that I can recommend are
+\url{http://www.andy-roberts.net/misc/latex/index.html} and 
+`` The (Not So) Short Introduction to LaTeX2e''
+(\url{http://ctan.tug.org/tex-archive/info/lshort/english/lshort.pdf}).
+
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Finally we specify the format required for our references and the
+%% name of the bibtex file where our references should be taken from.
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+\bibliographystyle{plainnat}
+\bibliography{example}
+
+\end{document}
diff --git a/test/issues/643/test.vim b/test/issues/643/test.vim
new file mode 100644
index 0000000..baa3b56
--- /dev/null
+++ b/test/issues/643/test.vim
@@ -0,0 +1,15 @@
+set nocompatible
+let &rtp  = '~/.vim/bundle/vimtex,' . &rtp
+let &rtp .= ',~/.vim/bundle/vimtex/after'
+filetype plugin indent on
+syntax enable
+
+" let g:vimtex_indent_delims_type = 'complex'
+
+silent edit test.tex
+profile start test.log
+profile func *
+profile file *
+silent! normal! gg=G
+profile pause
+quit!