\name{StatisticToMeta}
\alias{StatisticToMeta}
\alias{StatisticToMetaMap}
\title{Creates a StatisticMeta object from a Statistic object}
\description{
  This takes a \code{\link{Statistic}} object from an Assessment Model
  Description and turns it into a \code{\link{StatisticMeta}} object
  suitable for including in a Pretest Description.
}
\usage{
StatisticToMeta(stat, vars, codeRule = NULL)
StatisticToMetaMap
}
\arguments{
  \item{stat}{An object of type \code{\link{Statistic}}.}
  \item{vars}{A list of \code{\link{varDescription}} objects. The names
    of the elements should correspond to the variable names.}
  \item{codeRule}{A coding rule value for passing to
    \code{\link{integerCodes}}.  Should be an integer or \code{NULL}.}
}
\details{
  This creates a new \code{StatisticMeta} object from a \code{Statistic}
  object.  The \code{type} of the result will depend on the value of
  \code{stat$class} by looking this up in the table defined by
  \code{StatisticToMetaMap}.

  The \code{name} of the \code{Statistic} is used as the \code{name} of
  the \code{StatisticMeta} and the \code{columnID} is generated by
  substituting \sQuote{.} for \sQuote{(} and removing \sQuote{)} in the
  \code{name}.  For \dQuote{Probability} type statistics, a trailing
  \sQuote{.} is added to the \code{columnID}.

  In the case of \dQuote{Probability} statistics, the \code{levels}
  field is set from the \code{levels} field of the 
  \code{\link{varDescription}} for the \code{reportingVariable}.  This
  is found by looking it up by name in the \code{vars} argument.

  In the case of \dQuote{Discrete} statistics, the
  \code{transtlationTable} field is set by applying
  \code{\link{integerCodes}} to the \code{levels} field of the 
  \code{\link{varDescription}} for the \code{reportingVariable}.  This
  is found by looking it up by name in the \code{vars} argument.
  The \code{codeRule} argument is used to control how these are coded in
  the CSV file:  a value of \code{NULL} produces string codes and a
  numeric value produces integer codes.
  
}
\value{
  An object of type \code{\link{StatisticMeta}} (see Details).
}
\references{
  \url{http://research.ets.org/~ralmond/StatShop/dataFormats.html}
}
\seealso{ \code{\link{Statistic}}, \code{\link{StatisticMeta}},
  \code{\link{varDescription}}, \code{\link{integerCodes}}
}
\examples{
   Skill1 <- varDescription("Skill1","Skill1",role="SM",
          levels=c("Advanced","Proficient", "Basic", "Below Basic"))
   Skill2 <- varDescription("Skill2","Skill2",role="SM",
          levels=c("Proficient", "Not Proficient"))

   varlist <- list(Skill1=Skill1, Skill2=Skill2)
 
   S1.margin <- Statistic(name="margin(Skill1)", class="Bayes Net Margin",
                reportOnUpdate=TRUE, model="System",
                reportingVars="Skill1")

   S2.mean <- Statistic(name="mean(Skill2)", class="Bayes Net Mean",
             reportOnUpdate=TRUE, model="System",
             reportingVars="Skill2")

   S2.mode <- Statistic(name="mode(Skill2)", class="Bayes Net Mode",
             reportOnUpdate=TRUE, model="System",
             reportingVars="Skill2")

   S1.margin.meta <- StatisticToMeta(S1.margin, varlist)
   S2.mean.meta <- StatisticToMeta(S2.mean, varlist)
   S2.mode.meta <- StatisticToMeta(S2.mode, varlist, 1) ## Integer coding
\dontshow{
stopifnot(
  S1.margin.meta$type == "Probability",
  S2.mean.meta$type == "Real",
  S2.mode.meta$type == "Discrete",

  S1.margin.meta$name == S1.margin$name,
  S2.mean.meta$name == S2.mean$name,
  S2.mode.meta$name == S2.mode$name,

  all.equal(S1.margin.meta$levels,Skill1$levels),
  all.equal(S2.mode.meta$translationTable,
    c("Proficient"=2,"Not Proficient"=1))
)
}
}
\keyword{manip}