:VimwikiGenerateTags now updates a potentially existing listing

instead of adding it to the end.
Ref #85

autoload/vimwiki/base.vim

@@ -465,10 +465,9 @@ endfunction " }}}
 
 " vimwiki#base#generate_links
 function! vimwiki#base#generate_links() "{{{
+  let lines = []
+
   let links = vimwiki#base#get_wikilinks(g:vimwiki_current_idx, 0)
-
-  call append(line('$'), substitute(g:vimwiki_rxH1_Template, '__Header__', 'Generated Links', ''))
-
   call sort(links)
 
   let bullet = repeat(' ', vimwiki#lst#get_list_margin()).
@@ -476,10 +475,15 @@ function! vimwiki#base#generate_links() "{{{
   for link in links
     let abs_filepath = vimwiki#path#abs_path_of_link(link)
     if !s:is_diary_file(abs_filepath)
-      call append(line('$'), bullet.
+      call add(lines, bullet.
             \ substitute(g:vimwiki_WikiLinkTemplate1, '__LinkUrl__', '\='."'".link."'", ''))
     endif
   endfor
+
+  let links_rx = '\m^\s*'.vimwiki#u#escape(vimwiki#lst#default_symbol()).' '
+
+  call vimwiki#base#update_listing_in_buffer(lines, 'Generated Links', links_rx,
+        \ line('$')+1, 1)
 endfunction " }}}
 
 " vimwiki#base#goto
@@ -1087,6 +1091,74 @@ function! vimwiki#base#nested_syntax(filetype, start, end, textSnipHl) abort "{{
   endif
 endfunction "}}}
 
+" creates or updates auto-generated listings in a wiki file, like TOC, diary
+" links, tags list etc.
+" - the listing consists of a level 1 header and a list of strings as content
+" - a:content_regex is used to determine how long a potentially existing list is
+" - a:default_lnum is the line number where the new listing should be placed if
+"   it's not already present
+" - if a:create is true, it will be created if it doesn't exist, otherwise it
+"   will only be updated if it already exists
+function! vimwiki#base#update_listing_in_buffer(strings, start_header,
+      \ content_regex, default_lnum, create) "{{{
+  " apparently, Vim behaves strange when files change while in diff mode
+  if &diff || &readonly
+    return
+  endif
+
+  " check if the listing is already there
+  let already_there = 0
+
+  let header_rx = '\m^\s*'.
+        \ substitute(g:vimwiki_rxH1_Template, '__Header__', a:start_header, '')
+        \ .'\s*$'
+
+  let start_lnum = 1
+  while start_lnum <= line('$')
+    if getline(start_lnum) =~# header_rx
+      let already_there = 1
+      break
+    endif
+    let start_lnum += 1
+  endwhile
+
+  if !already_there && !a:create
+    return
+  endif
+
+  let old_cursor_pos = getpos('.')
+
+  if already_there
+    " delete the old listing
+    let whitespaces_in_first_line = matchstr(getline(start_lnum), '\m^\s*')
+    let end_lnum = start_lnum + 1
+    while end_lnum <= line('$') && getline(end_lnum) =~# a:content_regex
+      let end_lnum += 1
+    endwhile
+    silent exe start_lnum.','.string(end_lnum - 1).'delete _'
+  else
+    let start_lnum = a:default_lnum
+    let whitespaces_in_first_line = ''
+  endif
+
+  " write new listing
+  let new_header = whitespaces_in_first_line
+        \ . substitute(g:vimwiki_rxH1_Template,
+        \ '__Header__', '\='."'".a:start_header."'", '')
+  call append(start_lnum - 1, new_header)
+  let start_lnum += 1
+  for string in a:strings
+    call append(start_lnum - 1, string)
+    let start_lnum += 1
+  endfor
+  " append an empty line if there is not one
+  if start_lnum <= line('$') && getline(start_lnum) !~# '\m^\s*$'
+    call append(start_lnum - 1, '')
+  endif
+
+  call setpos('.', old_cursor_pos)
+endfunction "}}}
+
 " WIKI link following functions {{{
 " vimwiki#base#find_next_link
 function! vimwiki#base#find_next_link() "{{{
@@ -1630,44 +1702,6 @@ endfunction " }}}
 " a:create == 1: creates or updates TOC in current file
 " a:create == 0: update if TOC exists
 function! vimwiki#base#table_of_contents(create)
-  " apparently, Vim behaves strange when files change while in diff mode
-  if &diff
-    return
-  endif
-
-  " look for existing TOC
-  let toc_header = '^\s*'.substitute(g:vimwiki_rxH1_Template, '__Header__',
-        \ '\='."'".g:vimwiki_toc_header."'", '').'\s*$'
-  let toc_line = 0
-  let lnum = 1
-  while lnum <= &modelines + 2 && lnum <= line('$')
-    if getline(lnum) =~# toc_header
-      let toc_line = lnum
-      break
-    endif
-    let lnum += 1
-  endwhile
-
-  if !a:create && toc_line <= 0
-    return
-  endif
-
-  let old_cursor_pos = getpos('.')
-  let bullet = vimwiki#lst#default_symbol().' '
-  let rx_bullet = vimwiki#u#escape(bullet)
-  let whitespaces = matchstr(getline(toc_line), '^\s*')
-
-  " delete old TOC
-  if toc_line > 0
-    let endoftoc = toc_line+1
-    while endoftoc <= line('$') && getline(endoftoc) =~# '^\s*'.rx_bullet.g:vimwiki_rxWikiLink.'\s*$'
-      let endoftoc += 1
-    endwhile
-    silent exe toc_line.','.string(endoftoc-1).'delete _'
-  else
-    let toc_line = 1
-  endif
-
   " collect new headers
   let headers = []
   let headers_levels = [['', 0], ['', 0], ['', 0], ['', 0], ['', 0], ['', 0]]
@@ -1678,6 +1712,9 @@ function! vimwiki#base#table_of_contents(create)
     endif
     let h_level = vimwiki#u#count_first_sym(line_content)
     let h_text = vimwiki#u#trim(matchstr(line_content, g:vimwiki_rxHeader))
+    if h_text ==# g:vimwiki_toc_header  " don't include the TOC's header itself
+      continue
+    endif
     let headers_levels[h_level-1] = [h_text, headers_levels[h_level-1][1]+1]
     for idx in range(h_level, 5) | let headers_levels[idx] = ['', 0] | endfor
 
@@ -1700,25 +1737,23 @@ function! vimwiki#base#table_of_contents(create)
     call add(headers, [h_level, h_complete_id, h_text])
   endfor
 
-  " write new TOC
+  let lines = []
-  call append(toc_line-1, whitespaces . substitute(g:vimwiki_rxH1_Template,
-        \ '__Header__', '\='."'".g:vimwiki_toc_header."'", ''))
-
   let startindent = repeat(' ', vimwiki#lst#get_list_margin())
   let indentstring = repeat(' ', vimwiki#u#sw())
+  let bullet = vimwiki#lst#default_symbol().' '
   for [lvl, link, desc] in headers
     let esc_link = substitute(link, "'", "''", 'g')
     let esc_desc = substitute(desc, "'", "''", 'g')
     let link = substitute(g:vimwiki_WikiLinkTemplate2, '__LinkUrl__',
           \ '\='."'".'#'.esc_link."'", '')
     let link = substitute(link, '__LinkDescription__', '\='."'".esc_desc."'", '')
-    call append(toc_line, startindent.repeat(indentstring, lvl-1).bullet.link)
+    call add(lines, startindent.repeat(indentstring, lvl-1).bullet.link)
-    let toc_line += 1
   endfor
-  if getline(toc_line+1) !~# '^\s*$'
+
-    call append(toc_line, '')
+  let links_rx = '\m^\s*'.vimwiki#u#escape(vimwiki#lst#default_symbol()).' '
-  endif
+
-  call setpos('.', old_cursor_pos)
+  call vimwiki#base#update_listing_in_buffer(lines, g:vimwiki_toc_header, links_rx,
+        \ 1, a:create)
 endfunction
 "}}}
 

autoload/vimwiki/diary.vim

@@ -121,36 +121,31 @@ fun! s:group_links(links) "{{{
   return result
 endfun "}}}
 
-fun! s:sort(lst) "{{{
+function! s:sort(lst) "{{{
   if VimwikiGet("diary_sort") ==? 'desc'
     return reverse(sort(a:lst))
   else
     return sort(a:lst)
   endif
-endfun "}}}
+endfunction "}}}
 
-fun! s:format_diary(...) "{{{
+function! s:format_diary(...) "{{{
   let result = []
 
-  call add(result, substitute(g:vimwiki_rxH1_Template, '__Header__', VimwikiGet('diary_header'), ''))
-
   if a:0
     let g_files = s:group_links(s:get_diary_links(a:1))
   else
     let g_files = s:group_links(s:get_diary_links())
   endif
 
-  " for year in s:rev(sort(keys(g_files)))
   for year in s:sort(keys(g_files))
     call add(result, '')
     call add(result, substitute(g:vimwiki_rxH2_Template, '__Header__', year , ''))
 
-    " for month in s:rev(sort(keys(g_files[year])))
     for month in s:sort(keys(g_files[year]))
       call add(result, '')
       call add(result, substitute(g:vimwiki_rxH3_Template, '__Header__', s:get_month_name(month), ''))
 
-      " for [fl, cap] in s:rev(sort(items(g_files[year][month])))
       for [fl, cap] in s:sort(items(g_files[year][month]))
         if empty(cap)
           let entry = substitute(g:vimwiki_WikiLinkTemplate1, '__LinkUrl__', fl, '')
@@ -165,46 +160,8 @@ fun! s:format_diary(...) "{{{
 
     endfor
   endfor
-  call add(result, '')
 
   return result
-endfun "}}}
-
-function! s:delete_diary_section() "{{{
-  " remove diary section
-  let old_pos = getpos('.')
-  let ln_start = -1
-  let ln_end = -1
-  call cursor(1, 1)
-  if search(substitute(g:vimwiki_rxH1_Template, '__Header__', VimwikiGet('diary_header'), ''), 'Wc')
-    let ln_start = line('.')
-    if search(g:vimwiki_rxH1, 'W')
-      let ln_end = line('.') - 1
-    else
-      let ln_end = line('$')
-    endif
-  endif
-
-  if ln_start < 0 || ln_end < 0
-    call setpos('.', old_pos)
-    return
-  endif
-
-  if !&readonly
-    exe ln_start.",".ln_end."delete _"
-  endif
-
-  call setpos('.', old_pos)
-endfunction "}}}
-
-function! s:insert_diary_section() "{{{
-  if !&readonly
-    let ln = line('.')
-    call append(ln, s:format_diary())
-    if ln == 1 && getline(ln) == ''
-      1,1delete
-    endif
-  endif
 endfunction "}}}
 
 " Diary index stuff }}}
@@ -300,8 +257,9 @@ function! vimwiki#diary#generate_diary_section() "{{{
   let current_file = vimwiki#path#path_norm(expand("%:p"))
   let diary_file = vimwiki#path#path_norm(s:diary_index())
   if vimwiki#path#is_equal(current_file, diary_file)
-    call s:delete_diary_section()
+    let content_rx = '^\%(\s*\* \)\|\%(^\s*$\)\|\%('.g:vimwiki_rxHeader.'\)'
-    call s:insert_diary_section()
+    call vimwiki#base#update_listing_in_buffer(s:format_diary(),
+          \ VimwikiGet('diary_header'), content_rx, line('$')+1, 1)
   else
     echom "vimwiki: You can generate diary links only in a diary index page!"
   endif

autoload/vimwiki/tags.vim

@@ -261,10 +261,6 @@ function! vimwiki#tags#generate_tags(...) abort "{{{
 
   let metadata = s:load_tags_metadata()
 
-  call append(line('$'), [
-        \ '',
-        \ substitute(g:vimwiki_rxH1_Template, '__Header__', 'Generated Tags', '') ])
-
   " make a dictionary { tag_name: [tag_links, ...] }
   let tags_entries = {}
   for entries in values(metadata)
@@ -277,19 +273,28 @@ function! vimwiki#tags#generate_tags(...) abort "{{{
     endfor
   endfor
 
+  let lines = []
   let bullet = repeat(' ', vimwiki#lst#get_list_margin()).
         \ vimwiki#lst#default_symbol().' '
   for tagname in sort(keys(tags_entries))
     if need_all_tags || index(specific_tags, tagname) != -1
-      call append(line('$'), [
+      call extend(lines, [
             \ '',
             \ substitute(g:vimwiki_rxH2_Template, '__Header__', tagname, ''),
             \ '' ])
       for taglink in tags_entries[tagname]
-        call append(line('$'), bullet . '[[' . taglink . ']]')
+        call add(lines, bullet .
+              \ substitute(g:vimwiki_WikiLinkTemplate1, '__LinkUrl__', taglink, ''))
       endfor
     endif
   endfor
+
+  let links_rx = '\m\%(^\s*$\)\|\%('.g:vimwiki_rxH2.'\)\|\%(^\s*'
+        \ .vimwiki#u#escape(vimwiki#lst#default_symbol()).' '
+        \ .g:vimwiki_rxWikiLink.'$\)'
+
+  call vimwiki#base#update_listing_in_buffer(lines, 'Generated Tags', links_rx,
+        \ line('$')+1, 1)
 endfunction " }}}
 
 " vimwiki#tags#complete_tags