Please add support for frontmatter, especially tags

[aquatix]

Description

Please support (markdown/yaml) frontmatter in Markdown files, especially parsing of the tags field to be used with WikiFzfTags and such.

I already have syntax highlighting for yaml frontmatter in my wiki.vim/markdown files through https://github.com/aquatix/dotfiles/blob/master/.vim/after/syntax/markdown.vim

Minimal working example

Syntax is like this:

/coffee.md
---
created: 2021-08-30
tags: drink, work, good, life
---

# Why coffee is good

It just is

Relevant vimrc config:

let g:wiki_root = '~/phren'
let g:wiki_filetypes = ['md']
let g:wiki_link_extension = '.md'
let g:wiki_link_target_type = 'md'
let g:wiki_tags_format_pattern = '\v%(^|\s)#\zs[^# ]+'
let g:wiki_tags_scan_num_lines = 500

nmap <leader>wf :WikiFzfTags <CR>
nmap <leader>wb :WikiGraphFindBacklinks <CR>
nmap <leader>ft :WikiFzfToc <CR>

[lervag]

Please support (markdown/yaml) frontmatter in Markdown files, especially parsing of the tags field to be used with WikiFzfTags and such.

Hmm... well; I'm not quite sure. wiki.vim is not a filetype plugin. So I don't think it makes sense to parse the yaml frontmatter.

But, I'm curious: Do you only use the yaml frontmatter for specifying tags? If so, then perhaps it would suffice to allow parsing a line at the top of the file similar to tags: word1, ... (the commas could be optional)?

I already have syntax highlighting for yaml frontmatter in my wiki.vim/markdown files through https://github.com/aquatix/dotfiles/blob/master/.vim/after/syntax/markdown.vim

Again, wiki.vim is not a filetype plugin; it is also not a syntax plugin. So this is not really relevant.

[aquatix]

I know it's not a filetype plugin, that's party why I mentioned I already have syntax highlighting for the frontmatter part of a markdown file, so you knew I wasn't asking that from wiki.vim :)

Basically I only use the frontmatter for the tags indeed (I specify creation dates in it too, but that's mainly for myself and because it fits in there; sometimes a more readable title).

So being able to parse a tags-line near the top like you mention, would certainly fullfill my wish for this ticket.

I was looking at the tags.gather_from_file(file) function in tags.vim to see if I could provide a patch, but I'm afraid my vim script skills are failing me there.

[lervag]

I know it's not a filetype plugin, that's party why I mentioned I already have syntax highlighting for the frontmatter part of a markdown file, so you knew I wasn't asking that from wiki.vim :)

Haha, ok. No problem. Notice, though, how "implied communication" sometimes fails. Simply "I know this is not a filetype plugin, but ..." would have been simpler. Again, no problem; and I'm not always clear in my own communication either, so no worries! :)

So being able to parse a tags-line near the top like you mention, would certainly fullfill my wish for this ticket.

Great. I'll look into it!

[aquatix]

I wasn't aware that it would trigger you, I included the highlighting part because it was something that I wasn't concerned about with regard to wiki.vim, not because I was literally thinking in terms of "not a filetype plugin" :)

Yeah, communication is... fun. And I already think of myself as someone who is slightly better with words.

Anyway, great that you're going to look into supporting that tag-line, it would really help with my personal wiki/second brain thingee :)

[lervag]

I've added an initial version now; please test. See :help g:wiki_tags_parsers, it should describe how to make it work for yaml files.

[aquatix]

I guess I'm a tad sleep deprived, but with the following config I get an error:

" wiki.vim
Plug 'lervag/wiki.vim'
" let g:wiki_root = '~/wiki'
let g:wiki_root = '~/phren'
let g:wiki_filetypes = ['md']
let g:wiki_link_extension = '.md'
let g:wiki_link_target_type = 'md'
" let g:wiki_mappings_use_defaults = 1
"support for #tag style tags instead of :tag:
let g:wiki_tags_format_pattern = '\v%(^|\s)#\zs[^# ]+'
" parse tags in lines that match "tags: keyword1, keyword2" in addition to the default parser:
let g:wiki_tags_parsers = [
            \ g:wiki#tags#default_parser,
            \ { 'match': {x -> x =~# '^tags: '}, 
            \ 'parse': {x -> split(matchstr(x, '^tags:\zs.*'), '[ ,]\+')}} 
            \ ] 
" number of lines from the top to scan for tags
let g:wiki_tags_scan_num_lines = 500
" search through the tags in the wiki
nmap <leader>wf :WikiFzfTags <CR>
" find backlinks to this document
nmap <leader>wb :WikiGraphFindBacklinks <CR>
" find in ToC/structure of the (markdown) file
nmap <leader>ft :WikiFzfToc <CR>

The error is about the default_parser config not being defined (yet? Do I have to be explicit about its config?) E121: Undefined variable: g:wiki#tags#default_parser.

I know you're not a helpdesk, but could you please help me spot my error? :)

[lervag]

I know you're not a helpdesk, but could you please help me spot my error? :)

I'm glad to help :)

I've pushed some further updates and changes. The following tag related config should work, I believe. Please test, I might have been to quick here... :p

" Use hashes instead of colons for default tag parser
let s:tag_parser = deepcopy(g:wiki#tags#default_parser)
let s:tag_parser.re_match = '\v%(^|\s)#\zs[^# ]+'
let s:tag_parser.re_findstart = '\v%(^|\s)#\zs[^# ]+'

let g:wiki_tag_parsers = [
            \ s:tag_parser,
            \ {'match': {x -> x =~# '^tags: '},
            \  'parse': {x -> split(matchstr(x, '^tags:\zs.*'), '[ ,]\+')}}
            \ ]

let g:wiki_tag_scan_num_lines = 500

Notice I've changed some of the option names (I'll make a release in not too long where I describe all the breaking changes).

[aquatix]

That looks nice, but my config can't still find the g:wiki#tags#default_parser, so the deepcopy fails, and subsequently s:tag_parser is not defined:

E121: Undefined variable: g:wiki#tags#default_parser
E116: Invalid arguments for function deepcopy(g:wiki#tags#default_parser)
line  451:
E121: Undefined variable: s:tag_parser
line  452:
E121: Undefined variable: s:tag_parser
line  456:
E121: Undefined variable: s:tag_parser
Error detected while processing /home/mbscholt/.dot/dotfiles/.vim/plugged/wiki.vim/plugin/wiki.vim:
line   61:
E121: Undefined variable: g:wiki#tags#default_parser
E116: Invalid arguments for function wiki#init#option

With the snippet from my .vimrc:

Plug 'lervag/wiki.vim'
" let g:wiki_root = '~/wiki'
let g:wiki_root = '~/phren'
let g:wiki_filetypes = ['md']
let g:wiki_link_extension = '.md'
let g:wiki_link_target_type = 'md'
" let g:wiki_mappings_use_defaults = 1
"support for #tag style tags instead of :tag: (hashes instead of colons)
let s:tag_parser = deepcopy(g:wiki#tags#default_parser)
let s:tag_parser.re_match = '\v%(^|\s)#\zs[^# ]+'
let s:tag_parser.re_findstart = '\v%(^|\s)#\zs[^# ]+'
" parse tags in lines that match "tags: keyword1, keyword2" in addition to the default parser:
let g:wiki_tags_parsers = [
            \ s:tag_parser,
            \ {'match': {x -> x =~# '^tags: '},
            \  'parse': {x -> split(matchstr(x, '^tags:\zs.*'), '[ ,]\+')}}
            \ ]
" number of lines from the top to scan for tags
let g:wiki_tags_scan_num_lines = 500
" search through the tags in the wiki
nmap <leader>wf :WikiFzfTags <CR>
" find backlinks to this document
nmap <leader>wb :WikiGraphFindBacklinks <CR>
" find in ToC/structure of the (markdown) file
nmap <leader>ft :WikiFzfToc <CR>

I just updated to your latest revision (thanks for the work!), with the above result.

[lervag]

Ok; the simplest solution until I find a better implementation:

"support for #tag style tags instead of :tag: (hashes instead of colons)
runtime autoload/wiki/tags.vim
let s:tag_parser = deepcopy(g:wiki#tags#default_parser)

This makes sure to source the tags.vim file, which defines the variable.

[lervag]

Please note that I changed the variable names: g:wiki_tags_... to g:wiki_tag_....

[lervag]

Ah! The problem is that you are doing these things before you're calling plug#end(). I understand the idea of keeping everything together, but I strongly recommend to separate the Plug ... section from the configuration section; for instance because of "gotchas" like this. The point is that the runtime path is not really changed until after plug#end(), which explains why the variable is not available.

[lervag]

And, to add, just to be clear: My simple solution above will not work, because autoload/wiki/tags.vim is not available until after plug#end() is called.

[lervag]

I've been thinking about this, and I think the current implementation is quite good. If you update your own config by separating the vim-plug section from your configuration section, then things should work. I understand this is somewhat inconvenient, but it should be a relatively quick job.

[aquatix]

That plug#end() part... makes painful sense and only goes to show that even after all those years, I'm far from guru level ;)

I moved the config to after the plug#end() and changed the vars to g:wiki_tag_* but somehow creating the tags list results in a non-usable format for fzf:

Error detected while processing function wiki#fzf#tags:                                                                                 
line   10:                                                                                                                              
E688: More targets than List items

It looks like this now:
https://github.com/aquatix/dotfiles/blob/wikitags/.vimrc#L523

Your help and work is much appreciated!