\begin{frame}[fragile]{Simple Core Language (Syntax)} \begin{goal}{} Arithmetic expressions: \begin{talign} \aexp \;\;\; {::=} \;\;\; \boldsymbol{n} \;\mid\; \boldsymbol{x} \;\mid\; (-\aexp) \;\mid\; (\aexp + \aexp) \;\mid\; (\aexp - \aexp) \;\mid\; (\aexp * \aexp) \end{talign} \end{goal} \pause where \begin{itemize}\vspace*{0.2ex}\setlength{\itemsep}{0.2ex} \item $\boldsymbol{n}$ is any integer numeral in $\setexp{ \ldots, -2, -1, 0, 1, 2, \ldots }$\pause{} \item $\boldsymbol{x}$ any variable\pause{} \item $*$ indicates multiplication\pause{} \end{itemize} \begin{exampleblock}{} \begin{itemize}\vspace*{0.2ex}\setlength{\itemsep}{0.2ex} \item $42$\pause{} \item $y$\pause{} \item $4 + (x - 3)$\pause{} \item $x + (x * (y - (5 + z)))$ \end{itemize} \end{exampleblock} \vspace{10cm} \end{frame}