\documentclass[10pt,a4paper]{article} % Packages \usepackage{fancyhdr} % For header and footer \usepackage{multicol} % Allows multicols in tables \usepackage{tabularx} % Intelligent column widths \usepackage{tabulary} % Used in header and footer \usepackage{hhline} % Border under tables \usepackage{graphicx} % For images \usepackage{xcolor} % For hex colours %\usepackage[utf8x]{inputenc} % For unicode character support \usepackage[T1]{fontenc} % Without this we get weird character replacements \usepackage{colortbl} % For coloured tables \usepackage{setspace} % For line height \usepackage{lastpage} % Needed for total page number \usepackage{seqsplit} % Splits long words. %\usepackage{opensans} % Can't make this work so far. Shame. Would be lovely. \usepackage[normalem]{ulem} % For underlining links % Most of the following are not required for the majority % of cheat sheets but are needed for some symbol support. \usepackage{amsmath} % Symbols \usepackage{MnSymbol} % Symbols \usepackage{wasysym} % Symbols %\usepackage[english,german,french,spanish,italian]{babel} % Languages % Document Info \author{logcat} \pdfinfo{ /Title (haskell-patterns.pdf) /Creator (Cheatography) /Author (logcat) /Subject (Haskell patterns Cheat Sheet) } % Lengths and widths \addtolength{\textwidth}{6cm} \addtolength{\textheight}{-1cm} \addtolength{\hoffset}{-3cm} \addtolength{\voffset}{-2cm} \setlength{\tabcolsep}{0.2cm} % Space between columns \setlength{\headsep}{-12pt} % Reduce space between header and content \setlength{\headheight}{85pt} % If less, LaTeX automatically increases it \renewcommand{\footrulewidth}{0pt} % Remove footer line \renewcommand{\headrulewidth}{0pt} % Remove header line \renewcommand{\seqinsert}{\ifmmode\allowbreak\else\-\fi} % Hyphens in seqsplit % This two commands together give roughly % the right line height in the tables \renewcommand{\arraystretch}{1.3} \onehalfspacing % Commands \newcommand{\SetRowColor}[1]{\noalign{\gdef\RowColorName{#1}}\rowcolor{\RowColorName}} % Shortcut for row colour \newcommand{\mymulticolumn}[3]{\multicolumn{#1}{>{\columncolor{\RowColorName}}#2}{#3}} % For coloured multi-cols \newcolumntype{x}[1]{>{\raggedright}p{#1}} % New column types for ragged-right paragraph columns \newcommand{\tn}{\tabularnewline} % Required as custom column type in use % Font and Colours \definecolor{HeadBackground}{HTML}{333333} \definecolor{FootBackground}{HTML}{666666} \definecolor{TextColor}{HTML}{333333} \definecolor{DarkBackground}{HTML}{8ACCFF} \definecolor{LightBackground}{HTML}{F0F8FF} \renewcommand{\familydefault}{\sfdefault} \color{TextColor} % Header and Footer \pagestyle{fancy} \fancyhead{} % Set header to blank \fancyfoot{} % Set footer to blank \fancyhead[L]{ \noindent \begin{multicols}{3} \begin{tabulary}{5.8cm}{C} \SetRowColor{DarkBackground} \vspace{-7pt} {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}} } \end{tabulary} \columnbreak \begin{tabulary}{11cm}{L} \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Haskell patterns Cheat Sheet}}}} \\ \normalsize{by \textcolor{DarkBackground}{logcat} via \textcolor{DarkBackground}{\uline{cheatography.com/27075/cs/12218/}}} \end{tabulary} \end{multicols}} \fancyfoot[L]{ \footnotesize \noindent \begin{multicols}{3} \begin{tabulary}{5.8cm}{LL} \SetRowColor{FootBackground} \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}} \\ \vspace{-2pt}logcat \\ \uline{cheatography.com/logcat} \\ \end{tabulary} \vfill \columnbreak \begin{tabulary}{5.8cm}{L} \SetRowColor{FootBackground} \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}} \\ \vspace{-2pt}Published 5th July, 2017.\\ Updated 5th July, 2017.\\ Page {\thepage} of \pageref{LastPage}. \end{tabulary} \vfill \columnbreak \begin{tabulary}{5.8cm}{L} \SetRowColor{FootBackground} \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Sponsor}} \\ \SetRowColor{white} \vspace{-5pt} %\includegraphics[width=48px,height=48px]{dave.jpeg} Measure your website readability!\\ www.readability-score.com \end{tabulary} \end{multicols}} \begin{document} \raggedright \raggedcolumns % Set font size to small. Switch to any value % from this page to resize cheat sheet text: % www.emerson.emory.edu/services/latex/latex_169.html \footnotesize % Small font. \begin{tabularx}{17.67cm}{x{8.635 cm} x{8.635 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{17.67cm}}{\bf\textcolor{white}{Composition and application}} \tn % Row 0 \SetRowColor{LightBackground} `(.) :: (b -\textgreater{} c) -\textgreater{} (a -\textgreater{} b) -\textgreater{}~a~-\textgreater{}~c` & function composition \tn % Row Count 4 (+ 4) % Row 1 \SetRowColor{white} `(\$) :: (a -\textgreater{} b) -\textgreater{} a -\textgreater{} b` & application operator, has low, right-associative binding precedence, for example \seqsplit{`f \$ g \$ h x  =  f (g (h x))`} \tn % Row Count 11 (+ 7) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{17.67cm}{x{8.635 cm} x{8.635 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{17.67cm}}{\bf\textcolor{white}{Monoid}} \tn % Row 0 \SetRowColor{LightBackground} \mymulticolumn{2}{x{17.67cm}}{typeclass where empty/append are defined} \tn % Row Count 1 (+ 1) % Row 1 \SetRowColor{white} \seqsplit{`mempty  :: Monoid} a =\textgreater{} a` & identity of mappend (mappend mempty x = x) \tn % Row Count 4 (+ 3) % Row 2 \SetRowColor{LightBackground} `mappend :: Monoid a =\textgreater{} a -\textgreater{} a -\textgreater{} a` & append two monoids (associative: brackets does not matter)\{\{nl\}\}`mappend x (mappend y z) = mappend (mappend x y) z` \tn % Row Count 10 (+ 6) % Row 3 \SetRowColor{white} `\textless{}\textgreater{}      :: Monoid m =\textgreater{} m -\textgreater{} m -\textgreater{} m` & infix synonym for mappend (`"he" \textless{}\textgreater{} "llo"`) \tn % Row Count 13 (+ 3) % Row 4 \SetRowColor{LightBackground} `mconcat :: {[}a{]} -\textgreater{} a` & fold list using mappend and mempty \tn % Row Count 15 (+ 2) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{17.67cm}{x{8.635 cm} x{8.635 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{17.67cm}}{\bf\textcolor{white}{Functor}} \tn % Row 0 \SetRowColor{LightBackground} \mymulticolumn{2}{x{17.67cm}}{typeclass where `fmap` (`map`/`\textless{}\$\textgreater{}`) is defined} \tn % Row Count 1 (+ 1) % Row 1 \SetRowColor{white} should satisfy laws & `fmap id == id`\{\{nl\}\}`fmap (f . g) == fmap f . fmap g` \tn % Row Count 4 (+ 3) % Row 2 \SetRowColor{LightBackground} `fmap :: Functor f =\textgreater{} (a -\textgreater{} b) -\textgreater{} f a -\textgreater{} f b` & map function over functor\{\{nl\}\}`fmap (+1) (Just 3)` is `Just 4` \tn % Row Count 8 (+ 4) % Row 3 \SetRowColor{white} `\textless{}\$\textgreater{}  :: Functor f =\textgreater{} (a -\textgreater{} b) -\textgreater{} f a -\textgreater{} f b` & function mapped over functor\{\{nl\}\}infix synonym for `fmap`\{\{nl\}\}`(+1) \textless{}\$\textgreater{} (Just 3)` is `Just 4` \tn % Row Count 13 (+ 5) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{17.67cm}{x{8.635 cm} x{8.635 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{17.67cm}}{\bf\textcolor{white}{Applicative}} \tn % Row 0 \SetRowColor{LightBackground} typeclass where `pure`/`\textless{}*\textgreater{}` are defined\{\{nl\}\}have `Functor` as super class & \{\{nl\}\}every instance of `Applicative` must have instance of `Functor`\{\{nl\}\}so `fmap` (`map`/`\textless{}\$\textgreater{}`) can be used \tn % Row Count 6 (+ 6) % Row 1 \SetRowColor{white} `pure :: Applicative f =\textgreater{} a -\textgreater{} f a` & create an instance of Applicative\{\{nl\}\}`pure 3 :: {[}Int{]} ` is `{[}3{]}`\{\{nl\}\}`pure 3 :: Maybe Int` is `Just 3`\{\{nl\}\}`pure (+3) :: Maybe (Int -\textgreater{} Int)` is `Just` a function from Int to Int\{\{nl\}\}`pure (+3) :: {[}Int -\textgreater{} Int{]}` is list of function\{\{nl\}\}`pure 1 :: IO Int` is how it is printed in ghci \tn % Row Count 21 (+ 15) % Row 2 \SetRowColor{LightBackground} `(\textless{}*\textgreater{}) :: Applicative f =\textgreater{} f (a -\textgreater{} b) -\textgreater{} f a -\textgreater{} f b` & sequential application / apply\{\{nl\}\}`Just (+1) \textless{}*\textgreater{} Just 1 :: Maybe Int` is `Just 2`\{\{nl\}\}`{[}(+1), (+2){]} \textless{}*\textgreater{} {[}0{]} :: {[}Int{]}` is `{[}1, 2{]}` \tn % Row Count 28 (+ 7) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \begin{tabularx}{17.67cm}{x{8.635 cm} x{8.635 cm} } \SetRowColor{DarkBackground} \mymulticolumn{2}{x{17.67cm}}{\bf\textcolor{white}{Monad}} \tn % Row 0 \SetRowColor{LightBackground} typeclass\{\{nl\}\}have `Applicative` as super class & \{\{nl\}\}every instance of `Monad` must have instance of `Applicative` and `Functor`\{\{nl\}\}so `fmap` (`map`/`\textless{}\$\textgreater{}`) and `\textless{}*\textgreater{}`/`pure` can be used \tn % Row Count 7 (+ 7) % Row 1 \SetRowColor{white} `return :: Monad m =\textgreater{} a -\textgreater{} m a` & is `pure` \tn % Row Count 9 (+ 2) % Row 2 \SetRowColor{LightBackground} `(\textgreater{}\textgreater{}) :: Monad m =\textgreater{} m a -\textgreater{} m b -\textgreater{} m b` & sequentially compose two monads, first is usually\{\{nl\}\}`Just 2 \textgreater{}\textgreater{} Just 3` is `Just 3`\{\{nl\}\}`Nothing \textgreater{}\textgreater{} Just 3` is `Nothing`\{\{nl\}\}`{[}9, 9{]} \textgreater{}\textgreater{} {[}0, 0, 0{]}` is `{[}0,0,0,0,0,0{]}` \tn % Row Count 18 (+ 9) % Row 3 \SetRowColor{white} `(\textgreater{}\textgreater{}=) :: Monad m =\textgreater{} m a -\textgreater{} (a -\textgreater{} m b) -\textgreater{} m b` & bind, sequentially compose two monads, value of first passed as argument to the second\{\{nl\}\}`Just 3 \textgreater{}\textgreater{}= \textbackslash{}x -\textgreater{} Just (x + 1)` is `Just 4`\{\{nl\}\}`Nothing \textgreater{}\textgreater{}= \textbackslash{}x -\textgreater{} Just (x + 1)` is `Nothing`\{\{nl\}\}`{[}0, 0{]} \textgreater{}\textgreater{}= \textbackslash{}x -\textgreater{} {[}x + 1{]}` is `{[}1, 1{]}`\{\{nl\}\}`{[}0, 0{]} \textgreater{}\textgreater{}= \textbackslash{}x -\textgreater{} {[}x + 1, 2{]}` is `{[}1,2,1,2{]}`\{\{nl\}\}`{[}{]} \textgreater{}\textgreater{}= \textbackslash{}x -\textgreater{} {[}x + 1{]}` is `{[}{]}` \tn % Row Count 34 (+ 16) \hhline{>{\arrayrulecolor{DarkBackground}}--} \end{tabularx} \par\addvspace{1.3em} \end{document}