vim9script

export def Do()
    var lines = []
    job_start(&equalprg, {
        in_io: "buffer", in_buf: bufnr("%"),
        callback: (chan, msg) => {
            lines = add(lines, msg)
        },
        exit_cb: (job, status) => {
            if status != 0
                for i in range(len(lines))
                    lines[i] = substitute(lines[i], "^[^:]\\+:", @% .. ":", "")
                endfor
                cgetexpr lines
                copen
                return
            endif
            var view = winsaveview()
            silent execute ":%!" .. &equalprg
            winrestview(view)
        }
    })
enddef