| % File src/library/base/man/Paren.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2008 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{Paren} |
| \alias{Paren} |
| \alias{(} |
| \alias{\{} |
| \title{Parentheses and Braces} |
| \usage{ |
| \special{( \dots )} |
| |
| \special{{ \dots }} |
| } |
| \description{ |
| Open parenthesis, \code{(}, and open brace, \code{\{}, are |
| \code{\link{.Primitive}} functions in \R. |
| |
| Effectively, \code{(} is semantically equivalent to the identity |
| \code{function(x) x}, whereas \code{\{} is slightly more interesting, |
| see examples. |
| } |
| \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. |
| } |
| \references{ |
| Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) |
| \emph{The New S Language}. |
| Wadsworth & Brooks/Cole. |
| } |
| \seealso{ |
| \code{\link{if}}, \code{\link{return}}, etc for other objects used in |
| the \R language itself. |
| |
| \code{\link{Syntax}} for operator precedence. |
| } |
| \examples{ |
| 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)} |
| } |
| \keyword{programming} |