Start Wildcard creation example

unify.tex

@@ -7,6 +7,19 @@
 
 \section{Unify}\label{sec:unify}
 
+\subsection{Adding Wildcards to the mix}
+%Wildcard creation. % TODO: Explain by the example from the Bad Honnef Talk
+%Wildcards are bound to a type.
+% and can therefore only be created at T <. a constraints
+% After a reduce step the information to which Type the wildcard was bound is lost!
+\begin{lstlisting}
+<X> List<X> concat(List<X> l, List<X> r){ ... }
+
+someList(){
+  return new List("String") :? new List(42);
+}
+\end{lstlisting}
+
 \subsection{Description}
 The \unify{} algorithm tries to find a solution for a set of constraints like
 $\set{\exptype{List}{String} \lessdot \tv{a}, \exptype{List}{Integer} \lessdot \tv{a}}$.