"returning temporary directory name \"" $result \
          "\" for prefix \"" $prefix \"...]
    }

    return $result
  }

  #
  # NOTE: This procedure attempts to extract a package version information
  #       from the specified file.  The fileName argument is the local file
  #       name to read.  This procedure may raise script errors.
  #
  proc extractVersionFromFile { fileName } {
    switch -exact -- [file tail $fileName] {
      VERSION {
        return [string trim [readFile $fileName]]
      }
      pkgIndex.eagle -
      pkgIndex.tcl {
        #
        # TODO: Evaluate the package index file in a new "safe"
        #       interpreter and obtain the newly added [package
        #       ifneeded] version(s)?
        #
        return ""
      }
    }
  }

  #
  # NOTE: This procedure checks if there is a higher version available of the
  #       specified package on the package file server.  The language argument
  #       must be one of the literal strings "eagle", "tcl", or "client".  The
  #       version argument must be one of the literal strings "8.4", "8.5", or
  #       "8.6" when the language is "tcl" -OR- the literal string "1.0" when
  #       the language is either "eagle" or "client".  The platform argument

          [appendArgs $fileName .asc] \
          [appendArgs $downloadFileName .asc] $usePgp
    }

    set localFileName [file join $persistentDirectory $fileName]

    set compare [package vcompare \
        [string trim [readFile $downloadFileName]] \
        [string trim [readFile $localFileName]]]
        [extractVersionFromFile $downloadFileName] \
        [extractVersionFromFile $localFileName]]

    if {[isEagle]} then {
      file delete -recursive -- $temporaryDirectory
    } else {
      file delete -force -- $temporaryDirectory
    }