The R Project SVN R

\name{getClass}
\alias{getClass}
\alias{getClassDef}
\title{Get Class Definition }
\description{
  Get the definition of a class.
}
\usage{
getClass(Class, .Force = FALSE)
getClassDef(Class, where=-1)
}
\arguments{
  \item{Class}{ the character-string name of the class.}
  \item{.Force}{ if \code{TRUE}, return \code{NULL} if the class is
    undefined; otherwise, an undefined class results in an error.}
  \item{where}{ where to search for the definition; by default,
    anywhere on the current search list.}
}
\details{
  A call to \code{getClass} returns the complete definition of the class
  supplied as a string, including all slots, etc. in classes that this
  class extends.  A call to \code{getClassDef} returns the definition of
  the class from that database, unadorned.  It's usually \code{getClass}
  you want.

  The statement that \code{getClass} fails if the class is undefined is
  not quite true at the moment.  A few special vector types and
  informally defined classes are allowed, and \code{getClass} returns
  \code{NULL} for these.  But don't count on it; eventually these holes
  in the class system should be plugged.

  In any case, if you really want to know whether a class is formally
  defined, call \code{\link{isClass}}.
}
\value{
  The object defining the class.  This is an object of class
  \code{"classRepEnvironment"}.  However, \emph{do not} deal with the
  contents of the object directly unless you are very sure you know what
  you're doing.  Even then, it is nearly always better practice to use
  functions such as \code{\link{setClass}} and \code{\link{setIs}}.
  Messing up a class object will cause great confusion.
}
\references{
  The web page \url{http://www.omegahat.org/RSMethods/index.html} is the
  primary documentation.

  The functions in this package emulate the facility for classes and
  methods described in \emph{Programming with Data} (John M. Chambers,
  Springer, 1998).  See this book for further details and examples.
}
\author{
  John Chambers
}
\seealso{
  \link{Classes},
  \code{\link{setClass}},
  \code{\link{isClass}}.
}
\examples{
getClass("numeric") ## a built in class

\testonly{
getClass("thisIsAnUndefinedClass", .Force = TRUE) ## returns NULL
try(getClass("thisIsAnUndefinedClass")) ## generates an error
try(getClassDef("thisIsAnUndefinedClass")) ## generates an error
}
}
\keyword{programming}
\keyword{classes}