\documentclass{article}

%include lhs2TeX.fmt

\setlength{\parindent}{0mm}
\addtolength{\parskip}{0.25\baselineskip}

\begin{document}

\section{Basic features}

\paragraph{Plain text}

Text is just entered like text:

\begin{verbatim}
Text is just entered like text:
\end{verbatim}

\paragraph{Code}

Code blocks:

\begin{code}
module Main where
main = putStrLn ("Hi " ++ foo 2 ++ "!")
\end{code}

entered with:

\begin{verbatim}
\begin{code}
module Main where
main = putStrLn ("Hi " ++ foo 2 ++ "!")
\end{code}
\end{verbatim}

\paragraph{Compilation to documentation}

Compiled to produce documentation:

\begin{verbatim}
$ lhs2TeX --poly lhsexample.lhs > lhsexample.tex
$ pdflatex lhsexample.tex
\end{verbatim}

\paragraph{Compilation to program}

Compiled to produce code:

\begin{verbatim}
$ lhs2TeX --code lhsexample.lhs > Main.hs
$ ghc --make Main.hs
\end{verbatim}

\section{`Luxury' features}

\paragraph{Formatting}

Code fragments are formatted according to formatting definitions, e.g. no formatting for @foo@ in the
code block using @foo@:

\begin{verbatim}
\begin{code}
foo x = bar 2 3
\end{code}
\end{verbatim}

results in

\begin{code}
foo x = bar x 3
\end{code}

but with

\begin{verbatim}
%format foo = "\mathbf{foo}"
\end{verbatim}

it results in:
%{
%format foo = "\mathbf{foo}"

\begin{code}
foo x = bar x 3
\end{code}
%}

\paragraph{Indentation}

|>= 2| consecutive spaces are interpreted as starting a new column:

\begin{verbatim}
\begin{code}
b     22  3   = 22 + 3
b     x   _   = x
bar   x   y  = show (b x y)
\end{code}
\end{verbatim}

gives:

\begin{code}
b     22  3   = 22 + 3
b     x   _   = x
bar   x   y  = show (b x y)
\end{code}

\paragraph{Inlined formatting}

Formatting and verbatim can be done during plain text, respectively by using vertical bars @|@ and at symbols |@|:

\begin{itemize}
\item
  \verb+|foo|+ gives |foo|.
\item
  \verb+@foo@+ gives @foo@.
\end{itemize}

\section{And then...}

... there is the rest explained in the |lhs2TeX| documentation.

\end{document}