\Header{call}{Function Calls}
\alias{is.call}{call}
\alias{as.call}{call}
\keyword{programming}{call}
\keyword{attribute}{call}
\begin{Usage}
\begin{verbatim}
call(name, ...)

is.call(expr)
as.call(expr)
\end{verbatim}
\end{Usage}
\begin{Value}
An unevaluated function call, that is, an unevaluated expression
which consists of the named function applied to the given arguments
(\texttt{name} must be a quoted string which gives
the name of a function to be called).

\texttt{is.call} is used to determine whether \texttt{expr} is a call.

It is not possible to coerce objects to mode call
(objects either are calls or they are not calls).
\texttt{as.call} returns its argument if it is a call and
otherwise terminates with an error message.\end{Value}
\begin{SeeAlso}
\texttt{\Link{do.call}} for calling a function by name and argument
list; \texttt{\Link{Recall}} for recursive calling of functions;  further
\texttt{\Link{is.language}}, \texttt{\Link{expression}}, \texttt{\Link{function}}.\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
is.call(call) #-> FALSE: Functions are NOT calls

# set up a function call to round with argument 10.5
cl <- call("round",10.5)
is.call(cl)# TRUE
cl
# such a call can also be evaluated.
eval(cl)# [1] 10
\end{ExampleCode}
\end{Examples}

