| % File src/library/base/man/isR.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2007 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{is.R} |
| \title{Are we using R, rather than S?} |
| \usage{ |
| is.R() |
| } |
| \alias{is.R} |
| \description{ |
| Test if running under \R. |
| } |
| |
| \details{ |
| The function has been written such as to correctly run in all versions |
| of \R, S and S-PLUS. |
| In order for code to be runnable in both \R and S dialects previous to |
| S-PLUS 8.0, your code must either define \code{is.R} or use it as |
| |
| \code{if (exists("is.R") && is.function(is.R) && is.R()) \{}\cr |
| \code{ }\emph{## R-specific code}\cr |
| \code{\} else \{}\cr |
| \code{ }\emph{## S-version of code}\cr |
| \code{\}} |
| } |
| \value{ |
| \code{is.R} returns \code{TRUE} if we are using \R and \code{FALSE} |
| otherwise. |
| } |
| \seealso{\code{\link{R.version}}, \code{\link{system}}.} |
| \examples{ |
| x <- stats::runif(20); small <- x < 0.4 |
| ## In the early years of R, 'which()' only existed in R: |
| if(is.R()) which(small) else seq(along = small)[small] |
| } |
| \keyword{environment} |
| \keyword{utilities} |