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\begin{frame}{LL Parsing}
  \begin{goal}{LL parsing}
    Parsing \emph{top-down} with a \emph{leftmost} strategy.
    \medskip
    
    Backtracking is \alert{not} allowed.
  \end{goal}
  \medskip
    
  LL parsing does not work for every context-free grammar.
  \pause\bigskip

  \begin{goal}{}
    Starting point is a context-free grammar $G = (V,T,S,P)$:
    \begin{itemize}
      \item \alert{without useless variables}
      \item $\lambda$-productions and unit productions are allowed\\
        (elimination often increases the size of the grammar)
    \end{itemize}
    \pause
    Steps of LL parsing:
    \begin{itemize}
      \item Construct sets $\first{A}$ and $\follow{A}$ for every variable $A$.
      \item Construct a parsing table.
      \item Parse the input word using the parsing table.
    \end{itemize}
  \end{goal}
\end{frame}