Fix TamedFJ introduction

tRules.tex

@@ -5,33 +5,56 @@
 %Input language only described here. It is standard Featherweight Java
 % we use the transformation to proof soundness. this could also be moved to the end. 
 % the constraint generation step assumes every method argument to be encapsulated in a let statement. This is the way Java is doing capture conversion
-
+We define our own calculus \TamedFJ{}, which is used as input aswell as output to our global type inference algorithm.
-The input to our algorithm is a typeless version of Featherweight Java.
+%We assume that the input to our algorithm is a program, which carries none of the optional type annotations.
+%After calculating a type solution we can insert all missing types and generate a correct program.
+%The input to our algorithm is a typeless version of Featherweight Java.
 The syntax is shown in figure \ref{fig:syntax} with optional type annotations highlighted in yellow.
 The respective type rules are defined by figure \ref{fig:expressionTyping} and \ref{fig:typing}.
-\TamedFJ{} is a subset of the calculus defined by \textit{Bierhoff} \cite{WildcardsNeedWitnessProtection}.
+\TamedFJ{} is practically a subset of the Featherweight Java calculus defined by \textit{Bierhoff} \cite{WildcardsNeedWitnessProtection}
+with the exception that method argument and return type annotations are optional.
 The point is that a correct and fully typed \TamedFJ{} program is also a correct Featherweight Java program,
 which is vital for our soundness proof (see chapter \ref{sec:soundness}).
 %The language is designed to showcase type inference involving existential types.
-This calculus is used as input aswell as output to our global type inference algorithm.
-We assume that the input to our algorithm is a program, which carries none of the optional type annotations.
-After calculating a type solution we can insert all missing types and generate a correct program.
 
 A method assumption consists out of a method name, a list of type parameters, a list of argument types, and a return type.
-The first argument type is the type of the surrounding class or the \texttt{this} parameter one could say.
+The first type in the list of argument types is the type of the surrounding class also known as the \texttt{this} parameter.
-For example the \texttt{add} method in listing \ref{lst:tamedfjSample} is represented by the assumption
+See figure \ref{fig:methodTypeExample} for an example:
-$\texttt{add} : \generics{\ol{X \triangleleft Object}}\ \type{X} \to \exptype{List}{\type{X}}$.
+Here the \texttt{add} method internally is treated as a method with two arguments,
-\begin{lstlisting}[style=java,caption=\TamedFJ{} sample, label=lst:tamedfjSample]
+because we add \texttt{this} to its argument list.
+Note that the type parameter $\type{A}$ of the surrounding class is part of the methods parameter list.
+%For example the \texttt{add} method in listing \ref{lst:tamedfjSample} is represented by the assumption
+%$\texttt{add} : \generics{\ol{X \triangleleft Object}}\ \type{X} \to \exptype{List}{\type{X}}$.
+\begin{figure}
+\center
+\begin{minipage}{0.49\textwidth}
+    %[style=java,caption=\TamedFJ{} sample, label=lst:tamedfjSample]
+\begin{lstlisting}
 class List<A extends Object> {
     List<A> add(A v){..,}
 }
 \end{lstlisting}
-TODO
+\end{minipage}
-\\[1em]
+\begin{minipage}{0.49\textwidth}
-\noindent
+\begin{align*}
+&\mathrm{\Pi} = \set{\\
+&\texttt{add} : \generics{\ol{A \triangleleft Object}}\ \exptype{List}{\type{A}},\type{A} \to \exptype{List}{\type{X}} \\
+&}
+\end{align*}
+\end{minipage}
+% \begin{minipage}{0.49\textwidth}
+% \begin{lstlisting}[style=java,caption=\TamedFJ{} sample, label=lst:tamedfjSample]
+% class List<A extends Object> {}
+% <A extends Object> List<A>
+%     add(List<A> this, A v){..,}
+% \end{lstlisting}
+% \end{minipage}
+\caption{\TamedFJ{} class and its corresponding method type environment}\label{fig:methodTypeExample}
+\end{figure}
+
 \textit{Additional Notes:}%
 \begin{itemize}
-\item Method parameters and return types are optional.
+%\item Method parameters and return types are optional.
 \item We still require type annotations for fields and generic class parameters.
 This is a design choice by us,
 as we consider them as data declarations which are given by the programmer.
@@ -85,6 +108,7 @@ $
 & & \ \ | & \texttt{let}\ \expr{x} \highlight{: \wcNtype{\Delta}{N}} = \expr{e} \ \texttt{in} \ \expr{e}\\
 & & \ \ | & \expr{e} \elvis{} \expr{e}\\
 \text{Variable contexts} & \Gamma & ::= & \overline{\expr{x}:\type{T}}\\
+\text{Method type environment} & \mathrm{\Pi} & ::= & \overline{ \texttt{m} : \generics{\ol{X \triangleleft N}}\ \ol{T} \to \type{T}}
 %\hline
 \end{array}
 $