# NOTE: TBD 
  # 
  proc getIfNeededVersions { interp fileName } { 
    set result [list] 
 
    set oldPackages [interp eval $interp [list package names]] 
    interp invokehidden $interp source $fileName 
    set newPackages [interp eval $interp [list package names]] 
    set oldPackageNames [interp eval $interp [list package names]] 
    interp invokehidden $interp source $fileName; # [package ifneeded], etc. 
    set newPackageNames [interp eval $interp [list package names]] 
 
    foreach package $newPackages { 
      if {[lsearch -exact $oldPackages $package] == -1} then { 
        lappend result [list $package [lsort -decreasing \ 
    foreach packageName $newPackageNames { 
      if {[lsearch -exact $oldPackageNames $packageName] == -1} then { 
        lappend result [list $packageName [lsort -decreasing \ 
            -command [list package vcompare] [interp eval \ 
            $interp [list package versions $package]]]] 
            $interp [list package versions $packageName]]]] 
      } 
    } 
 
    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 } { 
  proc extractVersionsFromFile { fileName } { 
    switch -exact -- [file tail $fileName] { 
      VERSION { 
        return [string trim [readFile $fileName]] 
        return [list [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)? 
        # 
        if {[catch {createInterp interp} error] == 0} then { 
          set result [getIfNeededVersions $interp $fileName] 
        } else { 
          pkgLog [appendArgs \ 
              "could not create interp to extract versions: " \ 
              $error] 
 
          set result [list] 
        } 
 
        if {[info exists interp]} then { 
          catch {interp delete $interp} 
          unset interp; # REDUNDANT 
        } 
 
        return "" 
        return $result 
      } 
    } 
  } 
 
  # 

        } 
 
        set localFileName [file join $persistentDirectory $fileName] 
 
        set compare [package vcompare \ 
            [extractVersionFromFile $downloadFileName] \ 
            [extractVersionFromFile $localFileName]] 
            [lindex [extractVersionsFromFile $downloadFileName] 0] \ 
            [lindex [extractVersionsFromFile $localFileName] 0]] 
 
        if {[isEagle]} then { 
          file delete -recursive -- $temporaryDirectory 
        } else { 
          file delete -force -- $temporaryDirectory