
          demand_load procname
          Attempt to load the specified procedure, either as an
          autoload function or by loading the package containing the
          procedure.  If the package indexes have not been loaded for
          all package libraries in TCLPATH, they will be loaded.
          Out-of-date library indexes will be rebuilt if they are
          writable.  The procedure returns 1 if the procedure was
          sucessfully loaded, or 0 if it was not.

          Duplicated package names are skipped, the first package of a
          given name found in the path is loaded.
