From 40fb30148f1cd86f47a97441b1b9d9d98a128a5e Mon Sep 17 00:00:00 2001
From: Julian Ospald <jospald@fh-bielefeld.de>
Date: Thu, 16 Apr 2015 01:31:42 +0200
Subject: [PATCH] Add pattern matching on MaybeInt

---
 VL1.tex | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/VL1.tex b/VL1.tex
index 51b3196..1a00127 100644
--- a/VL1.tex
+++ b/VL1.tex
@@ -520,6 +520,18 @@ calcSomething x
 \end{lstlisting}
 \end{frame}
 
+\begin{frame}[fragile]
+\frametitle{Algebraic Data Types (ctn.)}
+And pattern match on it as well:
+\setHaskellCodeStyle
+\begin{lstlisting}
+addIntToList :: MaybeInt -> [Int]
+addIntToList (NoError x) = [x]
+addIntToList (Error str) = []
+\end{lstlisting}
+So if we got an error, we just return an empty list, otherwise we return a list with the \code{Int} as its only element.
+\end{frame}
+
 \begin{frame}[fragile]
 \frametitle{Algebraic Data Types (ctn.)}
 Let's define something more complex. How about a tree?