I made some custom commands to make writing equation blocks easier:

```
% Equation starters
\newcommand{\eqn}[1]{\begin{equation} #1 \end{equation}}
\newcommand{\eqns}[1]{\begin{equation*} #1 \end{equation*}}
\newcommand{\eqna}[1]{\begin{align} #1 \end{align}}
\newcommand{\eqnas}[1]{\begin{align*} #1 \end{align*}}
```

This is so that

```
\begin{equation}
e^{i \tau} = 1
\end{equation}
```

gets simplified to

```
\eqn{
e^{i \tau} = 1
}
```

In the second line, the syntax highlighting inside the \eqn{} block is wrong, because vim doesn't realise it's maths. Now, I just need to tell vim what I have done. I have no idea how, though.