\section{INPUT Get Input From User}

\subsection{Usage}

The \verb|input| function is used to obtain input from the user.  There are
two syntaxes for its use.  The first is
\begin{verbatim}
    r = input('prompt')
\end{verbatim}
in which case, the prompt is presented, and the user is allowed to enter
an expression.  The expression is evaluated in the current workspace or
context (so it can use any defined variables or functions), and returned
for assignment to the variable (\verb|r| in this case).  In the second form
of the \verb|input| function, the syntax is
\begin{verbatim}
    r = input('prompt','s')
\end{verbatim}
in which case the text entered by the user is copied verbatim to the
output.
