docs/manual/tips.tex

   1
   2 \section{Tips and Tricks}
   3
   4 \subsection{How to remove useless parentheses?}
   5
   6 If you want to rewrite any access to a pointer value by a function
   7 call, you may use the following semantic patch.
   8
   9 \begin{lstlisting}[language=Cocci]
  10 @-- a = *b
  11 @++ a = readb(b)
  12 \end{lstlisting}
  13
  14 However, if for some reason your code looks like \verb|bar = *(foo)|,
  15 you will end up with \verb|bar = readb((foo))| as the extra
  16 parentheses around \texttt{foo} are capture by the metavariable
  17 \texttt{b}.
  18
  19 In order to generate better output code, you can use the following
  20 semantic patch instead.
  21 \begin{lstlisting}[language=Cocci]
  22 @-- a = *(b)
  23 @++ a = readb(b)
  24 \end{lstlisting}
  25
  26 \noindent
  27 And rely on your standard.iso isomorphism file which should contain:
  28 \begin{lstlisting}[language=Cocci]
  29 Expression
  30 @ paren @
  31 expression E;
  32 @@
  33
  34  (E) => E
  35 \end{lstlisting}
  36
  37 Coccinelle will then consider \verb|bar = *(foo)| as equivalent to
  38 \verb|bar = *foo| (but not the other way around) and capture both.
  39 Finally, it will generate \verb|bar = readb(foo)| as expected.
  40
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