The R Project SVN R

% File src/library/utils/man/getS3method.Rd

% Part of the R package, http://www.R-project.org

% Copyright 1995-2012 R Core Team

% Distributed under GPL 2 or later

\name{getS3method}

\alias{getS3method}

\title{Get An S3 Method}

\description{

  Get a method for an S3 generic, possibly from a namespace or the

  generic's registry.

}

\usage{

getS3method(f, class, optional = FALSE)

}

\arguments{

  \item{f}{character: name of the generic.}

  \item{class}{character: name of the class.}

  \item{optional}{logical: should failure to find the generic or a

    method be allowed?}

}

\details{

  S3 methods may be hidden in namespaces, and will not

  then be found by \code{\link{get}}: this function can retrieve

  such functions, primarily for debugging purposes.

  Further, S3 methods can be registered on the generic when a namespace

  is loaded, and the registered method will be used if none is visible

  (using namespace scoping rules).

  It is possible that which S3 method will be used may depend on where

  the generic \code{f} is called from: \code{getS3method} returns the

  method found if \code{f} were called from the same environment.

}

\value{

  The function found, or \code{NULL} if no function is found and

  \code{optional = TRUE}.

}

\seealso{

  \code{\link{methods}}, \code{\link{get}}, \code{\link{getAnywhere}}

}

\examples{

require(stats)

exists("predict.ppr") # false

getS3method("predict", "ppr")

}

\keyword{data}