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\documentclass[dvipsnames,14pt,t]{beamer}
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\usepackage{beamerthemeplainculight}
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\usepackage[T1]{fontenc}
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\usepackage[latin1]{inputenc}
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\usepackage{mathpartir}
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\usepackage[absolute,overlay]{textpos}
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\usepackage{ifthen}
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\usepackage{tikz}
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\usepackage{pgf}
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\usepackage{calc}
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\usepackage{ulem}
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\usepackage{courier}
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\usepackage{listings}
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\renewcommand{\uline}[1]{#1}
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\usetikzlibrary{arrows}
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\usetikzlibrary{automata}
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\usetikzlibrary{shapes}
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\usetikzlibrary{shadows}
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\usetikzlibrary{positioning}
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\usetikzlibrary{calc}
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\usepackage{graphicx}
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\definecolor{javared}{rgb}{0.6,0,0} % for strings
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\definecolor{javagreen}{rgb}{0.25,0.5,0.35} % comments
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\definecolor{javapurple}{rgb}{0.5,0,0.35} % keywords
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\definecolor{javadocblue}{rgb}{0.25,0.35,0.75} % javadoc
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\lstset{language=Java,
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basicstyle=\ttfamily,
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keywordstyle=\color{javapurple}\bfseries,
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stringstyle=\color{javagreen},
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commentstyle=\color{javagreen},
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morecomment=[s][\color{javadocblue}]{/**}{*/},
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numbers=left,
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numberstyle=\tiny\color{black},
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stepnumber=1,
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numbersep=10pt,
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tabsize=2,
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showspaces=false,
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showstringspaces=false}
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\lstdefinelanguage{scala}{
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morekeywords={abstract,case,catch,class,def,%
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do,else,extends,false,final,finally,%
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for,if,implicit,import,match,mixin,%
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new,null,object,override,package,%
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private,protected,requires,return,sealed,%
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super,this,throw,trait,true,try,%
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type,val,var,while,with,yield},
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otherkeywords={=>,<-,<\%,<:,>:,\#,@},
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sensitive=true,
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morecomment=[l]{//},
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morecomment=[n]{/*}{*/},
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morestring=[b]",
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morestring=[b]',
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morestring=[b]"""
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}
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\lstset{language=Scala,
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basicstyle=\ttfamily,
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keywordstyle=\color{javapurple}\bfseries,
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stringstyle=\color{javagreen},
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commentstyle=\color{javagreen},
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morecomment=[s][\color{javadocblue}]{/**}{*/},
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numbers=left,
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numberstyle=\tiny\color{black},
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stepnumber=1,
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numbersep=10pt,
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tabsize=2,
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showspaces=false,
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showstringspaces=false}
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% beamer stuff
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\renewcommand{\slidecaption}{AFL 01, King's College London, 26.~September 2012}
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\begin{document}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}<1>[t]
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\frametitle{%
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\begin{tabular}{@ {}c@ {}}
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1
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\\[-3mm]
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\LARGE Automata and \\[-2mm]
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\LARGE Formal Languages (1)\\[-3mm]
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\end{tabular}}
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\begin{center}
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\includegraphics[scale=0.3]{pics/ante1.jpg}\hspace{5mm}
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\includegraphics[scale=0.31]{pics/ante2.jpg}\\
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\footnotesize\textcolor{gray}{Antikythera automaton, 100 BC (Archimedes?)}
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\end{center}
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\normalsize
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\begin{center}
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\begin{tabular}{ll}
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Email: & christian.urban at kcl.ac.uk\\
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Of$\!$fice: & S1.27 (1st floor Strand Building)\\
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Slides: & KEATS
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\end{tabular}
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\end{center}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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\begin{textblock}{1}(2,5)
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\begin{tabular}{c}
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\includegraphics[scale=0.15]{pics/servers.png}\\[-2mm]
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\small Server
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\end{tabular}
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\end{textblock}
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\begin{textblock}{1}(5.6,4)
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\begin{tikzpicture}[scale=1.1]
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\draw[white] (0,1) node (X) {};
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\draw[white] (2,1) node (Y) {};
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\draw[white] (0,0) node (X1) {};
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\draw[white] (2,0) node (Y1) {};
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\draw[white] (0,-1) node (X2) {};
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\draw[white] (2,-1) node (Y2) {};
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\draw[red, <-, line width = 2mm] (X) -- (Y);
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\node [inner sep=5pt,label=above:\textcolor{black}{GET request}] at ($ (X)!.5!(Y) $) {};
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\draw[red, ->, line width = 2mm] (X1) -- (Y1);
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\node [inner sep=5pt,label=above:\textcolor{black}{webpage}] at ($ (X1)!.5!(Y1) $) {};
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\draw[red, <-, line width = 2mm] (X2) -- (Y2);
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\node [inner sep=7pt,label=above:\textcolor{black}{POST data}] at ($ (X2)!.5!(Y2) $) {};
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\end{tikzpicture}
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\end{textblock}
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\begin{textblock}{1}(9,5.5)
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\begin{tabular}{c}
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\includegraphics[scale=0.15]{pics/laptop.png}\\[-2mm]
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\small Browser
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\end{tabular}
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\end{textblock}
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\only<2>{
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\begin{textblock}{10}(2,13.5)
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\begin{itemize}
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\item programming languages, compilers
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\end{itemize}
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\end{textblock}}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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transforming strings into structured data\\[10mm]
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{\LARGE\bf Lexing}\medskip\\
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\hspace{5mm}(recognising ``words'')\\[6mm]
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{\LARGE\bf Parsing}\medskip\\
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\hspace{5mm}(recognising ``sentences'')
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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The subject is quite old:
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\begin{itemize}
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\item Turing Machines, 1936
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\item first compiler for COBOL, 1957 (Grace Hopper)
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\item but surprisingly research papers are still published now
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\end{itemize}
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\begin{flushright}
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\includegraphics[scale=0.3]{pics/hopper.jpg}\\
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\footnotesize\textcolor{gray}{Grace Hopper}
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\end{flushright}
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{\footnotesize\textcolor{gray}{(she made it to David Letterman's Tonight Show, \url{http://www.youtube.com/watch?v=aZOxtURhfEU})}}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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\frametitle{\begin{tabular}{c}This Course\end{tabular}}
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\begin{itemize}
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\item the ultimate goal is to implement a small web-browser (really small one)\bigskip
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\end{itemize}
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Let's start with:
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\begin{itemize}
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\item a web-crawler
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\item an email harvester
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\item a web-scraper
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\end{itemize}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[t]
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\frametitle{\begin{tabular}{c}A Web-Crawler\end{tabular}}
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\mbox{}\\[10mm]
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\begin{enumerate}
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\item given an URL, read the corresponding webpage
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\item extract all links from it
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\item call the web-crawler again for all these links
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\end{enumerate}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[t]
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\frametitle{\begin{tabular}{c}A Web-Crawler\end{tabular}}
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\mbox{}\\[10mm]
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\begin{enumerate}
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\item given an URL, read the corresponding webpage
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\item if not possible print, out a problem
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\item if possible, extract all links from it
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\item call the web-crawler again for all these links
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\end{enumerate}\bigskip\pause
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\small (we need a bound for the number of recursive calls)
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\small (the purpose is to check all links on my own webpage)
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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\frametitle{\begin{tabular}{c}Scala\end{tabular}}
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\footnotesize a simple Scala function for reading webpages\\[-3mm]
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{\lstset{language=Scala}\fontsize{8}{10}\selectfont
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\texttt{\lstinputlisting{app0.scala}}}\pause
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{\lstset{language=Scala}\fontsize{8}{10}\selectfont
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\texttt{\lstinline{get_page("""http://www.inf.kcl.ac.uk/staff/urbanc/""")}}}\pause\bigskip
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\footnotesize slightly more complicated for handling errors properly:\\[-3mm]
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\footnotesize
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{\lstset{language=Scala}\fontsize{8}{10}\selectfont
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\texttt{\lstinputlisting{app1.scala}}}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[t]
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\frametitle{\begin{tabular}{c}A Regular Expression\end{tabular}}
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\begin{itemize}
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\item \ldots{} is a pattern or template for specifying strings
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\end{itemize}\bigskip
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\begin{center}
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\only<1>{{\lstset{language=Scala}\fontsize{18}{19}\selectfont\bf
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\texttt{"https?://[$\hat{\hspace{2mm}}$"]*"}}}%
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\only<2>{{\lstset{language=Scala}\fontsize{18}{19}\selectfont\bf
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\texttt{"""\textbackslash{}"https?://[$\hat{\hspace{2mm}}$\textbackslash{}"]*\textbackslash{}"""".r}}}
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\end{center}\bigskip\bigskip
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matches for example\\
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\;{\lstset{language=Scala}\fontsize{12}{14}\selectfont\bf
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\texttt{"http://www.foobar.com"}}\\
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\;{\lstset{language=Scala}\fontsize{12}{14}\selectfont\bf
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\texttt{"https://www.tls.org"}}\\
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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{\lstset{language=Scala}\fontsize{18}{19}\selectfont\bf
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\texttt{rexp.findAllIn(string)}}\medskip
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returns a list of all (sub)strings that match the regular expression\bigskip\bigskip
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{\lstset{language=Scala}\fontsize{18}{19}\selectfont\bf
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\texttt{rexp.findFirstIn(string)}}\medskip
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returns either {\bf\texttt{None}} if no (sub)string matches
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or {\bf\texttt{Some(s)}} with the first (sub)string
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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{\lstset{language=Scala}\fontsize{8}{10}\selectfont
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\texttt{\lstinputlisting{app2.scala}}}\medskip
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{\lstset{language=Scala}\fontsize{8}{10}\selectfont
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\texttt{crawl(some\_start\_URL, 2)}}\
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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\footnotesize
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a version that only ``crawls'' links in my domain:
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{\lstset{language=Scala}\fontsize{8}{10}\selectfont
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\texttt{\lstinputlisting{app3.scala}}}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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\footnotesize
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a little email ``harvester'':
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{\lstset{language=Scala}\fontsize{8}{10}\selectfont
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\texttt{\lstinputlisting{app4.scala}}}\bigskip
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\tiny
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\textcolor{gray}{\url{http://net.tutsplus.com/tutorials/other/8-regular-expressions-you-should-know/}}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\newcommand{\bl}[1]{\textcolor{blue}{#1}}
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\mode<presentation>{
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\begin{frame}[t]
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\frametitle{\begin{tabular}{c}Regular Expressions\end{tabular}}
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Their inductive definition:\medskip
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\begin{textblock}{6}(2,5)
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\begin{tabular}{@ {}rrl@ {\hspace{13mm}}l}
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\bl{r} & \bl{$::=$} & \bl{$\varnothing$} & null\\
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& \bl{$\mid$} & \bl{$\epsilon$} & empty string / "" / []\\
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& \bl{$\mid$} & \bl{c} & character\\
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& \bl{$\mid$} & \bl{r$_1$ $\cdot$ r$_2$} & sequence\\
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& \bl{$\mid$} & \bl{r$_1$ + r$_2$} & alternative / choice\\
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& \bl{$\mid$} & \bl{r$^*$} & star (zero or more)\\
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\end{tabular}
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\end{textblock}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[t]
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\frametitle{\begin{tabular}{c}Regular Expressions\end{tabular}}
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\small
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In Scala:
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{\lstset{language=Scala}\fontsize{8}{10}\selectfont
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\texttt{\lstinputlisting{app51.scala}}}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\newcommand{\dn}{\stackrel{\mbox{\scriptsize def}}{=}}% for definitions
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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\frametitle{\begin{tabular}{c}The Meaning of a\\[-2mm] Regular Expression\end{tabular}}
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\begin{textblock}{15}(1,4)
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\begin{tabular}{@ {}rcl}
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\bl{$L$($\varnothing$)} & \bl{$\dn$} & \bl{$\varnothing$}\\
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\bl{$L$($\epsilon$)} & \bl{$\dn$} & \bl{$\{$""$\}$}\\
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\bl{$L$(c)} & \bl{$\dn$} & \bl{$\{$"c"$\}$}\\
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\bl{$L$(r$_1$ + r$_2$)} & \bl{$\dn$} & \bl{$L$(r$_1$) $\cup$ $L$(r$_2$)}\\
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\bl{$L$(r$_1$ $\cdot$ r$_2$)} & \bl{$\dn$} & \bl{$\{$ s$_1$ @ s$_2$ $|$ s$_1$ $\in$ $L$(r$_1$) $\wedge$ s$_2$ $\in$
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$L$(r$_2$) $\}$}\\
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\bl{$L$(r$^*$)} & \bl{$\dn$} & \onslide<4->{\bl{$\bigcup_{n \ge 0}$ $L$(r)$^n$}}\\
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\end{tabular}\bigskip
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\onslide<2->{
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\hspace{5mm}\bl{$L$(r)$^0$ $\;\dn\;$ $\{$""$\}$}\\
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\bl{$L$(r)$^{n+1}$ $\;\dn\;$ $L$(r) @ $L$(r)$^n$}\hspace{9mm}\onslide<3->{\small\textcolor{gray}{(append on sets)}\\
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\small\hspace{5cm}\textcolor{gray}{$\{$ s$_1$ @ s$_2$ $|$ s$_1$ $\in$ $L$(r) $\wedge$ s$_2$ $\in$
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$L$(r)$^n$ $\}$}}
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}
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\end{textblock}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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\frametitle{\begin{tabular}{c}The Meaning of Matching\end{tabular}}
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\large
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a regular expression \bl{r} matches a string \bl{s} is defined as
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\begin{center}
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\bl{s $\in$ $L$(r)}\\
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\end{center}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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\frametitle{\begin{tabular}{c}This Course\end{tabular}}
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We will have a look at:
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\begin{itemize}
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7
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\item regular expressions / regular expression matching
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3
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\item automata
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\item the Myhill-Nerode theorem
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\item parsing
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\item grammars
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\item a small interpreter / web browser
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\end{itemize}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\mode<presentation>{
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\begin{frame}[c]
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\frametitle{\begin{tabular}{c}Exam\end{tabular}}
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0
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\begin{itemize}
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7
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\item The question ``Is this relevant for the exam?'' is not appreciated!\bigskip\\
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0
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Whatever is in the homework sheets (and is not marked ``optional'') is relevant for the
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exam.\\ No code needs to be written in the exam.
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\end{itemize}
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\end{frame}}
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\end{document}
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%%% Local Variables:
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%%% mode: latex
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%%% TeX-master: t
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%%% End:
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