% !TEX program = xelatex

\documentclass[dvipsnames,14pt,t,xelatex,aspectratio=169,xcolor={table}]{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}

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\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\\

    %                & \onslide<2>{\alert{PDF: A Crash-Course in Scala}}\bigskip\\

    %Office Hours: &  Thursdays 12:00 -- 14:00\\

  \end{tabular}

  \end{center}

\end{frame}

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%\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}

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\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}

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\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}

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\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}

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\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}

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\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}{10}(4,12)

\LARGE{}\phantom{b}

\only<-2>{\boldmath\textcolor{gray}{$a$}}\only<3->{\boldmath\alert{$a$}}%

\only<-3>{\boldmath\textcolor{gray}{$b$}}\only<4->{\boldmath\alert{$b$}}%

\only<-4>{\boldmath\textcolor{gray}{$a$}}\only<5->{\boldmath\alert{$a$}}%

\only<-5>{\boldmath\textcolor{gray}{$a$}}\only<6->{\boldmath\alert{$a$}}%

\only<-6>{\boldmath\textcolor{gray}{$a$}}\only<7->{\boldmath\alert{$a\quad\Rightarrow \textbf{yes}$}}% 

\end{textblock}

\end{frame}

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\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}

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\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}

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\begin{frame}[c]

\frametitle{Where to go on from here?}

\begin{itemize}

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

\item Haskell, Ocaml, Standard ML, Scheme, \ldots 

\end{itemize}  

\end{frame}

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\begin{frame}[c,fragile]

\frametitle{\alert{Questions?}}

{\tiny

\begin{verbatim}

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                     *   *           *   *

                    * * * *         * * * *

                   *       *       *       *

                  * *     * *     * *     * *

                 *   *   *   *   *   *   *   *

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               *                               *

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            * * * *                         * * * *

           *       *                       *       *

          * *     * *                     * *     * *

         *   *   *   *                   *   *   *   *

        * * * * * * * *                 * * * * * * * *

       *               *               *               *