freepascal.compiler/docs/syntax/operator.syn

\begin{diagram}{Operator definitions}{operatordef}
\begin{mysyntdiag}
\synt{operator\ definition} 
\lit*{operator}
\begin{stack}
\synt{assignment\ operator\ definition} \\
\synt{arithmetic\ operator\ definition} \\
\synt{comparision\ operator\ definition}
\end{stack}
\begin{stack}
\synt{result\ identifier} \\
\end{stack}
\lit*{:}
\synt{result\ type}
\lit*{;}
\synt{subroutine\ block}
\end{mysyntdiag}
\begin{mysyntdiag}
\synt{assignment\ operator\ definition}
\lit*{:=}
\lit*{(}
\synt{value\ parameter}
\lit*{)}
\end{mysyntdiag}
\begin{mysyntdiag}
\synt{arithmetic\ operator\ definition}
\begin{stack}
\lit*{+}\\
\lit*{-}\\
\lit*{*}\\
\lit*{/}\\
\lit*{**}
\end{stack}
\lit*{(}
\synt{parameter\ list}
\lit*{)}
\end{mysyntdiag}
\begin{mysyntdiag}
\synt{comparision\ operator\ definition}
\begin{stack}
\verb+ = + \\
\verb+ < + \\
\verb+ <= + \\
\verb+ > + \\
\verb+ >= +
\end{stack}
\lit*{(}
\synt{parameter\ list}
\lit*{)}
\end{mysyntdiag}
\end{diagram}