\begin{camlexample}{toplevel}
\begin{caml}
\begin{camlinput}
$\?$[@@@warning "+A"];;
\end{camlinput}
\end{caml}
\begin{caml}
\begin{camlinput}
$\?$1 + <<2.>> ;;
\end{camlinput}
\begin{camlerror}
$\:$Error: This expression has type float but an expression was expected of type
$\:$         int
\end{camlerror}
\end{caml}
\begin{caml}
\begin{camlinput}
$\?$let f <<x>> = () ;;
\end{camlinput}
\begin{camlwarn}
$\:$Warning 27: unused variable x.
$\:$val f : 'a -> unit = <fun>
\end{camlwarn}
\end{caml}
\end{camlexample}

\begin{camlexample}{toplevel}
\begin{caml}
\begin{camlinput}
$\?$Format.printf "Hello@.";
$\?$print_endline "world";;
\end{camlinput}
\begin{camloutput}
$\:$Hello
$\:$world
$\:$- : unit = ()
\end{camloutput}
\end{caml}
\end{camlexample}