\HeaderA{Paren}{Parentheses and Braces}{Paren}
\keyword{programming}{Paren}
\begin{Description}\relax
Open parenthesis, \code{(}, and open brace, \code{\{}, are
\code{\LinkA{.Primitive}{.Primitive}} functions in \R.

Effectively, \code{(} is semantically equivalent to the identity
\code{function(x) x}, whereas \code{\{} is slightly more interesting,
see examples.
\end{Description}
\begin{Usage}
\begin{verbatim}
( ... )

{ ... }
\end{verbatim}
\end{Usage}
\begin{Value}
For \code{(}, the result of evaluating the argument.  This has
visibility set, so will auto-print if used at top-level.

For \code{\{}, the result of the last expression evaluated. This has
the visibility of the last evaluation.
\end{Value}
\begin{References}\relax
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
\emph{The New S Language}.
Wadsworth \& Brooks/Cole.
\end{References}
\begin{SeeAlso}\relax
\code{\LinkA{if}{if}}, \code{\LinkA{return}{return}}, etc for other objects used in
the \R{} language itself.

\code{\LinkA{Syntax}{Syntax}} for operator precedence.
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
f <- get("(")
e <- expression(3 + 2 * 4)
identical(f(e), e)

do <- get("{")
do(x <- 3, y <- 2*x-3, 6-x-y); x; y

## note the differences
(2+3)
{2+3; 4+5}
(invisible(2+3))
{invisible(2+3)}
\end{ExampleCode}
\end{Examples}

