% !TEX program = xelatex
\documentclass[dvipsnames,14pt,t,xelatex]{beamer}
\usepackage{../slides}
\usepackage{../graphics}
\usepackage{../langs}
%%\usepackage{../data}
%%\usepackage[export]{adjustbox}
\usetikzlibrary{shapes,arrows,shadows}


\hfuzz=220pt 

%\setmonofont[Scale=.88]{Consolas}
%\newfontfamily{\consolas}{Consolas}

\lstset{language=Scala,
        style=mystyle,
        numbersep=0pt,
        numbers=none,
        xleftmargin=0mm}

\newcommand{\bl}[1]{\textcolor{blue}{#1}}     

% beamer stuff 
\renewcommand{\slidecaption}{PEP (Scala) 05, King's College London}

\begin{document}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[t]
\frametitle{%
  \begin{tabular}{@ {}c@ {}}
  \\[5mm]
  \huge PEP Scala (5) 
  \end{tabular}}

  \normalsize
  \begin{center}
  \begin{tabular}{ll}
    Email:  & christian.urban at kcl.ac.uk\\
    Office: & N\liningnums{7.07} (North Wing, Bush House)\bigskip\\
    Slides \& Code: & KEATS\\
                    & \onslide<2>{\alert{PDF: A Crash-Course in Scala}}\bigskip\\
    Office Hours: &  Thursdays 12:00 -- 14:00\\
    Additionally: & (for Scala) Tuesdays 10:45 -- 11:45\\ 
  \end{tabular}
  \end{center}

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     

\begin{frame}[c]
\frametitle{Marks for Preliminary 8}

Raw marks (265 submissions):\bigskip

\begin{itemize}
\item 4\%: \hspace{4mm}211
\item 3\%: \hspace{4mm}11
\item 2\%: \hspace{4mm}14
\item 1\%: \hspace{4mm}8
\item 0\%: \hspace{4mm}21
\end{itemize}\bigskip\bigskip  

\footnotesize
(plagiarism/collusion interviews ongoing again!)

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     

\begin{frame}[c]
\frametitle{Plan for Today}

\begin{itemize}
\item Being Lazy
\item Polymorphic Types
\item Immutable OOP
\item Making Fun about Scala
\end{itemize}

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
\begin{frame}[c,fragile]
\frametitle{How To calcululate 100 Mio Collatz Series?} 

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=1mm]
(1L to 100_000_000).map(collatz).max
\end{lstlisting}

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
\begin{frame}[c,fragile]
\frametitle{Polyorphic Types} 

To be avoided:\bigskip\bigskip
\small

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-6mm]
def length_string_list(lst: List[String]): Int = 
 lst match {
   case Nil => 0
   case x::xs => 1 + length_string_list(xs)
 }


def length_int_list(lst: List[Int]): Int = 
 lst match {
   case Nil => 0
   case x::xs => 1 + length_int_list(xs)
 }
\end{lstlisting}

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
\begin{frame}[c,fragile]
\frametitle{Polyorphic Types} 

\small

\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-6mm]
def length[A](lst: List[A]): Int = lst match {
  case Nil => 0
  case x::xs => 1 + length(xs)
}

length(List("1", "2", "3", "4"))
length(List(1, 2, 3, 4))


def map[A, B](lst: List[A], f: A => B): List[B] = 
 lst match {
   case Nil => Nil
   case x::xs => f(x)::map(xs, f) 
 }
\end{lstlisting}
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[c]
\frametitle{DFAs}  

\begin{center}
\begin{tikzpicture}[>=stealth',very thick,auto,
  every state/.style={minimum size=0pt,inner sep=2pt,
    draw=blue!50,very thick,fill=blue!20},]
  
\only<1,3->{\node[state,initial] (Q_0)  {$\mbox{Q}_0$};}
\only<2>{\node[state,initial,fill=red] (Q_0)  {$\mbox{Q}_0$};}  
\only<1,2,4->{\node[state] (Q_1) [right=of Q_0] {$\mbox{Q}_1$};}
\only<3>{\node[state,fill=red] (Q_1) [right=of Q_0] {$\mbox{Q}_1$};}
\only<-3,5->{\node[state] (Q_2) [below right=of Q_0] {$\mbox{Q}_2$};}
\only<4>{\node[state,fill=red] (Q_2) [below right=of Q_0] {$\mbox{Q}_2$};}
\only<-4,6->{\node[state] (Q_3) [right=of Q_2] {$\mbox{Q}_3$};}
\only<5>{\node[state,fill=red] (Q_3) [right=of Q_2] {$\mbox{Q}_3$};}
\only<-5>{\node[state, accepting] (Q_4) [right=of Q_1] {$\mbox{Q}_4$};}
\only<6->{\node[state, accepting,fill=red] (Q_4) [right=of Q_1] {$\mbox{Q}_4$};}

\path[->] (Q_0) edge node [above]  {\alert{$a$}} (Q_1);
\path[->] (Q_1) edge node [above]  {\alert{$a$}} (Q_4);
\path[->] (Q_4) edge [loop right] node  {\alert{$a, b$}} ();
\path[->] (Q_3) edge node [right]  {\alert{$a$}} (Q_4);
\path[->] (Q_2) edge node [above]  {\alert{$a$}} (Q_3);
\path[->] (Q_1) edge node [right]  {\alert{$b$}} (Q_2);
\path[->] (Q_0) edge node [above]  {\alert{$b$}} (Q_2);
\path[->] (Q_2) edge [loop left] node  {\alert{$b$}} ();
\path[->] (Q_3) edge [bend left=95, looseness=1.3] node [below]  {\alert{$b$}} (Q_0);
\end{tikzpicture}
\end{center}

\begin{textblock}{9}(4,12)
\LARGE{}
\only<3->{\boldmath\alert{$a$}}%
\only<4->{\boldmath\alert{$b$}}%
\only<5->{\boldmath\alert{$a$}}%
\only<6->{\boldmath\alert{$a$}}%
\only<7->{\boldmath\alert{$a\quad\Rightarrow \textbf{yes}$}}% 
\end{textblock}
  
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[t]
\frametitle{DFAs}

A \alert{\bf deterministic finite automaton} (DFA) consists of
5 things:

\begin{itemize}
\item an alphabet \bl{$\varSigma$}  
\item a set of states \bl{$\mbox{Qs}$}
\item one of these states is the start state \bl{$\mbox{Q}_0$}
\item some states are accepting states \bl{$F$}, and
\item there is transition function \bl{$\delta$}\bigskip 

\small
which takes a state  and a character as arguments and produces a 
new state; this function might not be everywhere defined 
\end{itemize}

\begin{center}
\bl{$A(\varSigma, \mbox{Qs}, \mbox{Q}_0, F, \delta)$}
\end{center}

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[c]
\frametitle{NFAs}  

\begin{center}
\begin{tikzpicture}[>=stealth',very thick, auto,
    every state/.style={minimum size=0pt,inner sep=3pt,
      draw=blue!50,very thick,fill=blue!20},scale=2]
\node[state,initial]  (Q_0)  {$\mbox{Q}_0$};
\node[state] (Q_1) [right=of Q_0] {$\mbox{Q}_1$};
\node[state, accepting] (Q_2) [right=of Q_1] {$\mbox{Q}_2$};
\path[->] (Q_0) edge [loop above] node  {\alert{$b$}} ();
\path[<-] (Q_0) edge node [below]  {\alert{$b$}} (Q_1);
\path[->] (Q_0) edge [bend left] node [above]  {\alert{$a$}} (Q_1);
\path[->] (Q_0) edge [bend right=45,looseness=1.3] node [below]  {\alert{$a$}} (Q_2);
\path[->] (Q_1) edge [loop above] node  {\alert{$a,b$}} ();
\path[->] (Q_1) edge node  [above] {\alert{$a$}} (Q_2);
\end{tikzpicture}
\end{center}

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\tikzstyle{sensor}=[draw, fill=blue!20, text width=3.8em, line width=1mm,
    text centered, minimum height=2em,drop shadow]
\tikzstyle{ann} = [above, text width=4em, text centered]
\tikzstyle{sc} = [sensor, text width=7em, fill=red!20, 
    minimum height=6em, rounded corners, drop shadow,line width=1mm]

\begin{frame}[fragile,c]
\frametitle{Compilers 6CCS3CFL}

\begin{tikzpicture}
    % Validation Layer is the same except that there are a set of nodes and links which are added
   
    \path (0,0) node (IR) [sc] {\textbf{WHILE Language}\\ compiler};
    \path (IR.west)+(-2.2,1.7) node (sou1) [sensor] {Fact};
    \path (IR.west)+(-2.2,0.5) node (sou2)[sensor] {Fib};
    \path (IR.west)+(-2.2,-0.7) node (sou4)[sensor] {Primes}; 
    \only<2>{\path (IR.west)+(-2.2,-1.9) node (sou3)[sensor] {BrainF**k};}    

    \path [draw,->,line width=1mm] (sou1.east) -- node [above] {} (IR.160);
    \path [draw,->,line width=1mm] (sou2.east) -- node [above] {} (IR.180);
    \only<2>{\path [draw,->,line width=1mm] (sou3.east) -- node [above] {} (IR.200);}
    \path [draw,->,line width=1mm] (sou4.east) -- node [above] {} (IR.190);

    \path (IR.east)+(2.2, 0.8) node (tar2)[sensor] {JVM};
    \path (IR.east)+(2.2,-0.8) node (tar3)[sensor] {LLVM{\small(x86)}}; 

    \path [draw,<-,line width=1mm] (tar2.west) -- node [above] {} (IR.5);
    \path [draw,<-,line width=1mm] (tar3.west) -- node [above] {} (IR.-5);

    
\end{tikzpicture}
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  \begin{frame}[c]
  \frametitle{Dijkstra on Testing}
  
  \begin{bubble}[10cm]
  ``Program testing can be a very effective way to show the
  presence of bugs, but it is hopelessly inadequate for showing
  their absence.''
  \end{bubble}\bigskip
  
  
  \end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[c]
\frametitle{\Large Proving Programs to be Correct}

\begin{bubble}[10cm]
\small
{\bf Theorem:} There are infinitely many prime 
numbers.\medskip\\

{\bf Proof} \ldots\\
\end{bubble}\bigskip


similarly\bigskip

\begin{bubble}[10cm]
\small
{\bf Theorem:} The program is doing what 
it is supposed to be doing.\medskip

{\bf Long, long proof} \ldots\\
\end{bubble}\bigskip\medskip

\small This can be a gigantic proof. The only hope is to have
help from the computer. `Program' is here to be understood to be
quite general (compiler, OS, \ldots).

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     

\begin{frame}[c]
\frametitle{Can This Be Done?}

\begin{itemize}
\item in 2011, verification of a small C-compiler (CompCert)
\begin{itemize}
\item ``if my input program has a certain behaviour, then the compiled machine code has the same behaviour''
\item is as good as \texttt{gcc -O1}, but much, much less buggy 
\end{itemize}
\end{itemize}

\begin{center}
  \includegraphics[scale=0.12]{../pics/compcert.png}
\end{center}

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% ~2,237,800 lines of proof in 474


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     
\begin{frame}[c]
\frametitle{Fuzzy Testing C-Compilers}

\begin{itemize}
\item tested GCC, LLVM and others by randomly generating 
C-programs
\item found more than 300 bugs in GCC and also
many in LLVM (some of them highest-level critical)\bigskip
\item about CompCert:

\begin{bubble}[10cm]\small ``The striking thing about our CompCert
results is that the middle-end bugs we found in all other
compilers are absent. As of early 2011, the under-development
version of CompCert is the only compiler we have tested for
which Csmith cannot find wrong-code errors. This is not for
lack of trying: we have devoted about six CPU-years to the
task.'' 
\end{bubble} 
\end{itemize}

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[c]
\frametitle{seL4 / Isabelle}

\begin{itemize}
\item verified a microkernel operating system ($\approx$8000 lines of C code)\bigskip
\item US DoD has competitions to hack into drones; they found that the
  isolation guarantees of seL4 hold up\bigskip
\item CompCert and seL4 sell their code  
\end{itemize}

\only<2>{
\begin{textblock}{5}(5.5,1.9)
  \includegraphics[scale=0.25]{../pics/drone.jpg}
\end{textblock}}

\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%     

\begin{frame}[c]
\frametitle{Where to go on from here?}

\begin{itemize}
\item Martin Odersky (EPFL)\ldots he is currently throwing out everything
  and starts again with the dotty compiler for Scala 3.0\medskip

\item Elm (\url{http://elm-lang.org})\ldots web applications with style\medskip   

\item Haskell, Ocaml, Standard ML, Scheme, \ldots 
\end{itemize}  
\end{frame}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{frame}[c,fragile]
\frametitle{\alert{Questions?}}

{\tiny
\begin{verbatim}
                               *
                              * *
                             *   *
                            * * * *
                           *       *
                          * *     * *
                         *   *   *   *
                        * * * * * * * *
                       *               *
                      * *             * *
                     *   *           *   *
                    * * * *         * * * *
                   *       *       *       *
                  * *     * *     * *     * *
                 *   *   *   *   *   *   *   *
                * * * * * * * * * * * * * * * *
               *                               *
              * *                             * *
             *   *                           *   *
            * * * *                         * * * *
           *       *                       *       *
          * *     * *                     * *     * *
         *   *   *   *                   *   *   *   *
        * * * * * * * *                 * * * * * * * *
       *               *               *               *
      * *             * *             * *             * *
     *   *           *   *           *   *           *   *
    * * * *         * * * *         * * * *         * * * *
   *       *       *       *       *       *       *       *
  * *     * *     * *     * *     * *     * *     * *     * *
 *   *   *   *   *   *   *   *   *   *   *   *   *   *   *   *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
\end{verbatim}}


\begin{textblock}{6}(8.5,3.5)
\begin{bubble}[5cm]
\footnotesize
\begin{lstlisting}[language=Scala, numbers=none, xleftmargin=-1mm]
++++++++[>+>++++<<-]>++>>
+<[-[>>+<<-]+>>]>+[-<<<[-
>[+[-]+>++>>>-<<]<[<]>>++
++++[<<+++++>>-]+<<++.[-]
<<]>.>+[>>]>+]
\end{lstlisting}
\end{bubble}
\end{textblock}
  
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 


\begin{frame}[t]

  \begin{center}  
  \includegraphics[scale=0.4]{../pics/mind2.jpg}
  \end{center}
  
  \begin{textblock}{14}(2,11.4)
  \large\bf{}Mind-Blowing Programming Languages:\\ 
  \centering Scala\;\;?
  \end{textblock}
\end{frame}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



\end{document}


\end{document}

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