gistfile1.txt

function! s:ParseMarkdown()
    let l:lines = getline(1,line("$"))
    let l:pages_lines = []
    let s:pages = ''
    echo "Parsing..."
 
    for l:line in l:lines
        if l:line =~ '^#\+'
            if !empty(l:pages_lines)
                let s:pages .= join(l:pages_lines[-1], "\r\n")
            endif
            
            call add(l:pages_lines, [ l:line ])
        elseif !empty(l:pages_lines)
            call add(l:pages_lines[-1], l:line)
        endif
    endfor
    
    let s:max_page_number = len(s:pages)-1
endfunction