Add GADTs section

Author: rudymatela

haskell-exts-cs.tex

@@ -110,5 +110,33 @@ \section{Generalized Algebraic Datatypes
 \begin{ldesc}
 \li[enabling] \C{\{-\# LANGUAGE GADTs\#-\}}
 \end{ldesc}\\[1ex]
+\begin{tabular}{CC}
+\theads{GADT}{regular data definition}
+\\
+data Maybe a where~~~~~~~~~~ & data~Maybe~a \\
+~~Nothing~::~Maybe~a & ~~=~Nothing \\
+~~Just~~~~::~a~->~Maybe~a & ~~|~Just~a \\
+\\
+data List a where & data List a \\
+~~Nil~~::~List a & ~~= Nil \\
+~~Cons~::~a -> List a -> List a & ~~| Cons a (List a) \\
+\\
+data [a] where & data [a] = [] | a:[a] \\
+~~[]~~::~[a] & ~~\rotatebox{90}{$\Rsh$}\textnormal{\footnotesize ~(not real Haskell)} \\
+~~(:)~::~a -> [a] -> [a] & \\
+\\
+data Thing a where & \textnormal{regular defn.~impossible} \\
+~~Thing ::~a -> Thing a & \\
+~~AnInt ::~Int -> Thing Int & \\
+~~ABool ::~Bool -> Thing Bool & \\
+\\
+data Nat where & data Nat = Z | S Nat \\
+~~Z~::~Nat & \\
+~~S~::~Nat -> Nat & \\
+\\
+data Vec n a where & \textnormal{regular defn.~impossible} \\
+~~Nil~~~::~Vec Z a & \\
+~~(:::)~::~a -> Vec n a -> Vec (S n) a \hspace{-8ex} & \\
+\end{tabular}
 
 \end{document}