          lappend varName value ?value value ...?
               Treat the variable given  by  varName  as  a  list  and
               append  each  of  the value arguments to that list as a
               separate element, with  spaces  between  elements.   If
               varName  doesn't  exist,  it  is created as a list with
               elements given by  the  value  arguments.   Lappend  is
               similar  to  append except that the values are appended
               as list elements rather than raw  text.   This  command
               provides  a  relatively efficient way to build up large
               lists.  For example, ``lappend  a  $b''  is  much  more
               efficient  than ``set a [concat $a [list $b]]'' when $a
               is long.
