src/Pure/Tools/imports.scala

   /* Isabelle tool wrapper */
 
   val isabelle_tool =
     Isabelle_Tool("imports", "maintain theory imports wrt. session structure", args =>
     {
+      var base_sessions: List[String] = Nil
       var select_dirs: List[Path] = Nil
       var operation_imports = false
       var operation_repository_files = false
       var requirements = false
       var operation_update = false

 
       val getopts = Getopts("""
 Usage: isabelle imports [OPTIONS] [SESSIONS ...]
 
   Options are:
+    -B NAME      include session NAME and all descendants
     -D DIR       include session directory and select its sessions
     -I           operation: report potential session imports
     -M           operation: Mercurial repository check for theory files
     -R           operate on requirements of selected sessions
     -U           operation: update theory imports to use session qualifiers

     -x NAME      exclude session NAME and all descendants
 
   Maintain theory imports wrt. session structure. At least one operation
   needs to be specified (see options -I -M -U).
 """,
+      "B:" -> (arg => base_sessions = base_sessions ::: List(arg)),
       "D:" -> (arg => select_dirs = select_dirs ::: List(Path.explode(arg))),
       "I" -> (_ => operation_imports = true),
       "M" -> (_ => operation_repository_files = true),
       "R" -> (_ => requirements = true),
       "U" -> (_ => operation_update = true),

       val sessions = getopts(args)
       if (args.isEmpty || !(operation_imports || operation_repository_files || operation_update))
         getopts.usage()
 
       val selection =
-        Sessions.Selection(requirements, all_sessions, exclude_session_groups,
+        Sessions.Selection(requirements, all_sessions, base_sessions, exclude_session_groups,
           exclude_sessions, session_groups, sessions)
 
       val progress = new Console_Progress(verbose = verbose)
 
       if (operation_imports || operation_repository_files ||