\Header{getDepList}{Functions to retrieve dependency information}
\alias{pkgDepends}{getDepList}
\keyword{utilities}{getDepList}
\begin{Description}\relax
Given a dependency matrix, will create a \code{DependsList} object for that
package which will include the dependencies for that matrix, which
ones are installed, which unresolved dependencies were found online,
which unresolved dependencies were not found online, and any R dependencies.
\end{Description}
\begin{Usage}
\begin{verbatim}
getDepList(depMtrx, instPkgs, recursive=TRUE, local=TRUE, reduce=TRUE,
           lib.loc=NULL)
pkgDepends(pkg, recursive = TRUE, local = TRUE, reduce = TRUE, lib.loc=NULL)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{depMtrx}] A dependency matrix as from \code{package.dependencies}
\item[\code{pkg}] The name of the package
\item[\code{instPkgs}] A matrix specifying all packages installed on the
local system, as from \code{installed.packages}
\item[\code{recursive}] Whether or not to include indirect dependencies
\item[\code{local}] Whether or not to search only locally
\item[\code{reduce}] Whether or not to collapse all sets of dependencies to a
minimal value
\item[\code{lib.loc}] What libraries to use when looking for installed
packages.  \code{NULL} indicates all library directories in the
user's \code{.libPaths()}.
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
The function \code{pkgDepends} is a convenience function which wraps
\code{getDepList} and takes as input a package name.  It will then
query \code{\Link{installed.packages}} and also generate a dependency
matrix, calling \code{getDepList} with this information and returning
the result.

These functions will retrieve information about the dependencies of
the matrix, resulting in a \code{DependsList} object.  This is a
list with four elements:
\describe{
\item[Depends] A vector of the dependencies for this package.
\item[Installed] A vector of the dependencies which have been
satisfied by the currently installed packages.
\item[Found] A list representing the dependencies which are not in
\code{Installed} but were found online.  This list has element
names which are the URLs for the repositories in which packages
were found and the elements themselves are vectors of package
names which were found in the respective repositories.  If
\code{local=TRUE}, the \code{Found} element will always be empty.
\item[R] Any R version dependencies.
}

If \code{recursive} is \code{TRUE}, any package that is specified as a
dependency will in turn have its dependencies included (and so on),
these are known as indirect dependencies.  If \code{recursive} is 
\code{FALSE}, only the dependencies directly stated by the package will 
be used.

If \code{local} is \code{TRUE}, the system will only look at the user's local
install and not online to find unresolved dependencies.

If \code{reduce} is \code{TRUE}, the system will collapse the fields in the
\code{DependsList} object such that a minimal set of dependencies
are specified (for instance if there was ('foo', 'foo (>= 1.0.0)',
'foo (>= 1.3.0)'), it would only return 'foo (>= 1.3.0)').
\end{Details}
\begin{Value}
An object of class \code{DependsList}
\end{Value}
\begin{Author}\relax
Jeff Gentry
\end{Author}
\begin{SeeAlso}\relax
\code{\Link{installFoundDepends}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
pkgDepends("tools", local = FALSE)
\end{ExampleCode}
\end{Examples}

