1076 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

  1077 \mode<presentation>{

  1078 \begin{frame}[c]

  1079 \frametitle{\begin{tabular}{c}An Interpreter\end{tabular}}

  1080 

  1081 \begin{center}

  1082 \bl{\begin{tabular}{l}

  1083 $\{$\\

  1084 \;\;$x := 5 \text{;}$\\

  1085 \;\;$y := x * 3\text{;}$\\

  1086 \;\;$y := x * 4\text{;}$\\

  1087 \;\;$x := u * 3$\\

  1088 $\}$

  1089 \end{tabular}}

  1090 \end{center}

  1091 

  1092 \begin{itemize}

  1093 \item the interpreter has to record the value of \bl{$x$} before assigning a value to \bl{$y$}\pause

  1094 \item \bl{\text{eval}(stmt, env)}

  1095 \end{itemize}

  1096 

  1097 

  1098 \end{frame}}

  1099 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

  1100 

  1101 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

  1102 \mode<presentation>{

  1103 \begin{frame}[c]

  1104 \frametitle{\begin{tabular}{c}Interpreter\end{tabular}}

  1105 

  1106 \begin{center}

  1107 \bl{\begin{tabular}{@{}lcl@{}}

  1108 $\text{eval}(n, E)$ & $\dn$ & $n$\\

  1109 $\text{eval}(x, E)$ & $\dn$ & $E(x)$ \;\;\;\textcolor{black}{lookup \bl{$x$} in \bl{$E$}}\\

  1110 $\text{eval}(a_1 + a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) + \text{eval}(a_2, E)$\\

  1111 $\text{eval}(a_1 - a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) - \text{eval}(a_2, E)$\\

  1112 $\text{eval}(a_1 * a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) * \text{eval}(a_2, E)$\bigskip\\

  1113 $\text{eval}(a_1 = a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) = \text{eval}(a_2, E)$\\

  1114 $\text{eval}(a_1\,!\!= a_2, E)$ & $\dn$ & $\neg(\text{eval}(a_1, E) = \text{eval}(a_2, E))$\\

  1115 $\text{eval}(a_1 < a_2, E)$ & $\dn$ & $\text{eval}(a_1, E) < \text{eval}(a_2, E)$\

  1116 \end{tabular}}

  1117 \end{center}

  1118 

  1119 \end{frame}}

  1120 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   

  1121 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

  1122 \mode<presentation>{

  1123 \begin{frame}[c]

  1124 \frametitle{\begin{tabular}{c}Interpreter (2)\end{tabular}}

  1125 

  1126 \begin{center}

  1127 \bl{\begin{tabular}{@{}lcl@{}}

  1128 $\text{eval}(\text{skip}, E)$ & $\dn$ & $E$\\

  1129 $\text{eval}(x:=a, E)$ & $\dn$ & \bl{$E(x \mapsto \text{eval}(a, E))$}\\

  1130 \multicolumn{3}{@{}l@{}}{$\text{eval}(\text{if}\;b\;\text{then}\;cs_1\;\text{else}\;cs_2 , E) \dn$}\\

  1131 \multicolumn{3}{@{}l@{}}{\hspace{2cm}$\text{if}\;\text{eval}(b,E)\;\text{then}\;

  1132 \text{eval}(cs_1,E)$}\\

  1133 \multicolumn{3}{@{}l@{}}{\hspace{2cm}$\phantom{\text{if}\;\text{eval}(b,E)\;}\text{else}\;\text{eval}(cs_2,E)$}\\

  1134 \multicolumn{3}{@{}l@{}}{$\text{eval}(\text{while}\;b\;\text{do}\;cs, E) \dn$}\\

  1135 \multicolumn{3}{@{}l@{}}{\hspace{2cm}$\text{if}\;\text{eval}(b,E)$}\\

  1136 \multicolumn{3}{@{}l@{}}{\hspace{2cm}$\text{then}\;

  1137 \text{eval}(\text{while}\;b\;\text{do}\;cs, \text{eval}(cs,E))$}\\

  1138 \multicolumn{3}{@{}l@{}}{\hspace{2cm}$\text{else}\; E$}\\

  1139 $\text{eval}(\text{write}\; x, E)$ & $\dn$ & $\{\;\text{println}(E(x))\; ;\;E\;\}$\\

  1140 \end{tabular}}

  1141 \end{center}

  1142 

  1143 \end{frame}}

  1144 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   

  1145 

  1146 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

  1147 \begin{frame}[c]

  1148 \frametitle{\begin{tabular}{c}Test Program\end{tabular}}

  1149 

  1150 \mbox{}\\[-18mm]\mbox{}

  1151 

  1152 {\lstset{language=While}%%\fontsize{10}{12}\selectfont

  1153 \texttt{\lstinputlisting{../progs/loops.while}}}

  1154 

  1155 \end{frame}

  1156 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%   

  1157 

  1158 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

  1159 \mode<presentation>{

  1160 \begin{frame}[t]

  1161 \frametitle{\begin{tabular}{c}Interpreted Code\end{tabular}}

  1162 

  1163 \begin{center}

  1164 \begin{tikzpicture}

  1165 \begin{axis}[axis x line=bottom, axis y line=left, xlabel=n, ylabel=secs, legend style=small]

  1166 \addplot+[smooth] file {interpreted.data};

  1167 \end{axis}

  1168 \end{tikzpicture}

  1169 \end{center}

  1170 

  1171 \end{frame}}

  1172 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 

  1173 

  1174 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

  1175 \mode<presentation>{

  1176 \begin{frame}[c]

  1177 \frametitle{\begin{tabular}{c}Java Virtual Machine\end{tabular}}

  1178 

  1179 \begin{itemize}

  1180 \item introduced in 1995

  1181 \item is a stack-based VM (like Postscript, CLR of .Net)

  1182 \item contains a JIT compiler

  1183 \item many languages take advantage of JVM's infrastructure (JRE)

  1184 \item is garbage collected $\Rightarrow$ no buffer overflows

  1185 \item some languages compile to the JVM: Scala, Clojure\ldots

  1186 \end{itemize}

  1187 

  1188 \end{frame}}

  1189 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%