bat/tests/syntax-tests/highlighted/Literate Haskell/Main.lhs

\documentclass{article}
 
\begin{document}
 
\section*{Introduction}
 
Text outside code environments should follow TeX/LaTeX highlighting.
 
The code environment delimiters themselves should be highlighted.
 
Text inside code environments should follow regular Haskell highlighting.
 
\begin{code}
import Data.List
import System.Environment
import Text.Printf
 
twoSumN :: Int -> [Int] -> [Int]
twoSumN _ [] = []
twoSumN n (x : xs) | (n - x) `elem` xs = [x, n - x]
| otherwise = twoSumN n xs
 
threeSumN :: Int -> [Int] -> [Int]
threeSumN _ [] = []
threeSumN n (x : xs) | null partial = threeSumN n xs
| otherwise = x : partial
where partial = twoSumN (n - x) xs
\end{code}
 
Text in-between code environments.
% LaTeX comment.
 
\begin{code}
output :: String -> IO ()
output path = do
input <- sort . map read . filter (not . null) . lines <$> readFile path
printf "File: %s\n" path
printf " Part 1: %d\n" . product . twoSumN 2020 $ input
printf " Part 2: %d\n" . product . threeSumN 2020 $ input
 
-- Haskell comment inside code environment.
 
main :: IO ()
main = getArgs >>= mapM_ output
\end{code}
 
\end{document}