SIGNATURE SeqMapEnv[env,from,to]

-- mappings of sequences with an accumulating environment

-- Parameter 
SORT env from to

IMPORT Seq[from] ONLY seq
       Seq[to]   ONLY seq

FUN * : (env ** from -> env ** to) ** env ** seq[from] -> env ** seq[to]
        -- f * (e,<>) == (e,<>)
        -- f * (e,ft::rt) == (e2,ft1::rt1)
        --		     WHERE (e1,ft1) == f(e,ft)  
        --			   (e2,rt1) == f * (e1,rt)