gistfile1.vim

function! s:echo_line_with_hl(lnum, sep)
  let line = getline(a:lnum)
  let cs = split(line, '\zs')
  let xs = []
  for c in range(1, len(line))
    if diff_hlID(a:lnum, c) isnot 0
      let name = synIDattr(synIDtrans(diff_hlID(a:lnum, c)), 'name')
    else
      let name = synIDattr(synIDtrans(synID(a:lnum, c, 1)), 'name')
    endif
    let xs += [[cs[c-1], (empty(name) ? 'None' : name)]]
  endfor
  let b = 1
  for x in xs
    echohl None
    if b
      echon 'hi: '
      let b = 0
    endif
    if x[0] is a:sep
      echo ''
      let b = 1
    else
      execute 'echohl ' . x[1]
      echon x[0]
    endif
  endfor
  echohl None
endfunction