\name{widgetInvoke}
\alias{widgetInvoke}
\title{A function to provide a graphical widget to call a function}
\description{
  This function will provide a graphical widget (currently using Gtk) to
  call a function.  The widget is defined previously by the package
  author and information about this widget is stored in an XML file,
  which is then read in by widgetInvoke.  The user's input is passed on
  directly to the appropriate function.
}
\usage{
widgetInvoke(funName, argOverides=list(), argsOnly=FALSE)
}
\arguments{
  \item{funName}{The name of the function}
  \item{argOverides}{Allows the user to customize the argument display
    on widgets}
  \item{argsOnly}{If this is set to \code{TRUE}, the internal argument
    list is returned instead of evaluated values.}
}
\details{
  The package that \code{funName} is in must already be loaded prior to
  running \code{widgetInvoke} for \code{widgetInvoke} to work properly.
  
  Calling this function will display a widget via \code{RGtk} to the
  user that allows them to graphically enter in the values for the
  function described by \code{funName}.  Then, upon hitting the
  \code{Evaluate} button, the values stored in the widget are passed
  directly to the requested function, which is then evaluated normally.

  The widget is constructed by information stored in an XML file, which
  must be generated by running \code{\link{createWF}} for \code{funName}
  prior to running \code{widgetInvoke}.

  Some arguments will have default values specified, which can be
  changed by the user.  Also, arguments may have been designated as
  being required to have a value before evaluation can take place, these
  arguments will have their name surrounded by \code{*} characters
  (e.g. \code{*colors*} or \code{*x*}).  If the user hits the
  \code{Evaluate} button and any of the required parameters do not have
  a value, the function will not be evaluated and the user will be
  warned of the situation.
  
  Note that with text entry boxes, values which the user intends to be
  treated as a character string must be quoted.  Any value which is not
  quoted will be treated in the same manner as usual for \R, in that it
  will be handled as a numerical value, a variable name, etc.

  If a user wishes to enter in a vector of values, the simplest manner
  would be to declare that vector as a variable before calling
  \code{widgetInvoke} and then using that variable as the value for an
  argument.  However, if the user wants to enter the vector in the
  actual entry spot, comma separated values are interpreted to be
  vectors.

  The \code{argOverides} argument allows the \code{widgetInvoke} user to
  customize their widget for a particular function.  The structure of
  this argument is a list, where for any argument that the user wishes
  to customize, an element is in the list w/ the same name as the
  argument.  That element itself is a list where elements are any slot
  of the function's \code{\link{wFun}} object's argument list
  (e.g. \code{argDefault}).  The value of these elements are used to
  replace the values that come from the XML file.  This use of this
  argument is not recommended for most users, and is primarily intended
  for the use of other software which is using the \code{widgetInvoke}
  function.  
}
\author{Jeff Gentry}
\seealso{\code{\link{createWF}}, \code{\link{wFun-class}}}
\examples{
  ## Coming soon
}
\keyword{interface}