" Goal: Create a line with: foobar1 foobar2 ... foobar19
" Note: the_isz solves this example without Nexus, using the much simpler:
"         join(map(range(1,19), '"foobar" . v:val'), " ")

" First approach is using normal mode commands and a substitute:
call s1.reset()
$
normal 19ix
s/x/\="foobar".s1.next()/g
normal o

" Second approach uses vimscript:
call s1.reset()
call setline('$', join(map(range(1,19), "printf('foobar%d', s1.next())"), ' '))
" alternatively, if you don't need printf power, use the simpler case below:
call setline('$', join(map(range(1,19), '"foobar".s1.next()'), ' '))