\name{TaskListFromSSXML}
\alias{TaskListFromSSXML}
%- Also NEED an '\alias' for EACH other topic documented here.
\title{Find unique TaskIDs in StatShop XML file}
\description{
  This function scans a StatShop XML file for \code{<TaskID>} elements
  and gathers a list of the unique task IDs.
}
\usage{
TaskListFromSSXML(xmlFile)
}
\arguments{
  \item{xmlFile}{A character string giving the name of a StatShop XML
    file.  This works will almost all types of StatShop files
    (\code{cpd.xml}---calibration pretest data, \code{pd.xml}---pretest
    description, \code{tdd.xml}---task data description,
    and \code{amd.xml}---assessment model description.  
}
}
\details{
  A common problem encountered in StatShop is a mismatch between the
  list of tasks in a pretest description \code{pd.xml} and a calibration
  pretest description \code{cpd.xml} file.  When this occurs,
  conversions to CSV format can cause large numbers of \code{NA}s in the
  CSV file.  Unexpected behavior can also occur if there is a mismatch
  between the list of task in the data file and in the assessment model
  description \code{amd.xml}.  This could cause task outcomes to be
  scored using generic evidence model rather than task specific links.

  The \code{TaskListFromSSXML()} function read an XML file and extract
  the unique \code{<TaskID>} elements.  These should be in \link{ECDID}
  format.  The results can be compared using \code{\link[base]{setdiff}}.
}
\value{
  A character vector contating task IDs in the \link{ECDID} format.  If
  the XML file does not contain \code{<TaskID>} elements, then the
  vector will have length zero.
}
\author{
  Russell Almond
}

%% ~Make other sections like Warning with \section{Warning }{....} ~

\seealso{
  \code{\link{ECDID}}, \code{\link[base]{setdiff}}, \code{\link{xmlTaskList}}
}
\examples{
# Assumes StatShop is installed on the test machine.
StatShop <- Sys.getenv("STATSHOP")
if (StatShop == "") {
  warn("StatShop not installed, skipping test.")
  } else {
  #Read in some standard task lists.
  pdtl <- TaskListFromSSXML(paste(StatShop, "xml",
                                  "DataDescription.pd.xml",
                                  sep=.Platform$file.sep))

  cpdtl <- TaskListFromSSXML(paste(StatShop, "xml",
                                  "PreCalibrationSample.cpd.xml",
                                  sep=.Platform$file.sep))
  amdtl <- TaskListFromSSXML(paste(StatShop, "xml",
                                  "BayesscoreAssessmentDescription.amd.xml",
                                  sep=.Platform$file.sep))
  ##check to make sure they are all the same.
  stopifnot(length(setdiff(pdtl,cpdtl)==0))
  stopifnot(length(setdiff(cpdtl,pdtl)==0))
  stopifnot(length(setdiff(amdtl,cpdtl)==0))
  stopifnot(length(setdiff(cpdtl,amdtl)==0))
  }
}
% Add one or more standard keywords, see file 'KEYWORDS' in the
% R documentation directory.
\keyword{interface}