[R] Wait for the user to type <Return>, depending on argument.

[Christian Hoffmann]

Hi,

I hope I will not bother you.

This is a useful tool in programming pauses:

function(ask) {
   if (ask & interactive() & sink.number()==0) readline("\nType 
<Return>\t to continue : ")
}

It guards against batch use and sink-ing:

for (ii in 1:5) {
     cat(ii,"\n")
     waitReturn(ii %% 2 == 1)
   }

sink("blafile")
for (ii in 1:5) {
     cat(ii,"\n")
     waitReturn(ii %% 2 == 1)
   }
sink()
#look at file "blafile"

Documentation: (R style)
\name{waitReturn}
\alias{waitReturn}
\title{Wait for <Return>}
\description{
   Wait for the user to type <Return>, depending on argument.
}
\usage{
   waitReturn(ask=TRUE)
}
\arguments{
   \item{ask}{ \code{TRUE} will generate the interruption, \code{FALSE} 
will not.}
}
\details{
   The interruption will only generated for the interactive use of R and
   if the call is not \code{sink}ed (where it would hang the process).
}
\value{
   None.
}

\examples{
   for (ii in 1:5) {
     cat(ii,"\n")
     waitReturn(ii %% 2 == 1)
   }
}
\author{Christian W. Hoffmann, \email{christian.hoffmann at wsl.ch},
	\url{http://www.wsl.ch/staff/christian.hoffmann}
}
\keyword{programming}


Christian


-- 
--  --> New telephone number, old one will work until 2006
Dr.sc.math.Christian W. Hoffmann, 
http://www.wsl.ch/staff/christian.hoffmann
Mathematics + Statistical Computing   e-mail: hoffmacw at wsl.ch
Swiss Federal Research Institute WSL  Tel: ++41-44-73922..  ..77  (self)
CH-8903 Birmensdorf, Switzerland            ..11(exchange), ..15  (Fax)