list concatenation
lc=lstcat(l1,..ln)
:li list or any other type of variable : :lc a list :
lc=lstcat(l1,..ln) catenates components of li lists in a single list. If the li are other type of variables they are simply added to the resulting list.
lstcat(`list`_(1,2,3),33,`list`_('foo',%s))
lstcat(1,2,3)