1042 \end{itemize}

  1042 \end{itemize}

  1043 We will elaborate on this, with the help of

  1043 We will elaborate on this, with the help of

  1044 some helper functions such as $\retrieve$ and

  1044 some helper functions such as $\retrieve$ and

  1045 $\flex$.

  1045 $\flex$.

  1046 \subsection{Specifications of Some Helper Functions}

  1046 \subsection{Specifications of Some Helper Functions}

  1048 the lexing process, which is not be possible

  1048 the lexing process, which is not be possible

  1049 using $\lexer$ or $\blexer$ alone.

  1049 using $\lexer$ or $\blexer$ alone.

  1050 \subsubsection{$\textit{Retrieve}$}

  1050 \subsubsection{$\textit{Retrieve}$}

  1051 The first function we shall introduce is $\retrieve$.

  1051 The first function we shall introduce is $\retrieve$.

  1052 Sulzmann and Lu gave its definition, and

  1052 Sulzmann and Lu gave its definition, and