Typeset Haskell code in LaTeX: an example of colorful lhs2TeX

main.lhs

% Build main.pdf:
%   lhs2TeX main.lhs -o main.tex
%   pdflatex main.tex

\documentclass{article}

%%%%%%%%%%%%%%  Color-related things   %%%%%%%%%%%%%%

\usepackage[dvipsnames]{xcolor}

%include polycode.fmt

%subst keyword a = "\textcolor{BlueViolet}{\textbf{" a "}}"

\newcommand{\id}[1]{\textsf{\textsl{#1}}}

\renewcommand{\Varid}[1]{\textcolor{Sepia}{\id{#1}}}
\renewcommand{\Conid}[1]{\textcolor{OliveGreen}{\id{#1}}}

%%%%%%%%%%%%  End of Color-related things   %%%%%%%%%%%%

% It might make sence to add pretty formating of individual things 
% like "forall", cf.
% https://github.com/goldfirere/thesis/blob/master/tex/rae.fmt

\begin{document}

\begin{code}
module ColorsInLhs2TeX where

newtype Foo = MkFoo Int

plusFoo :: Foo -> Foo -> Int
plusFoo (MkFoo n) (MkFoo m) = n + m
\end{code}

\end{document}

Result: