Vim9: no tag is generated for ":def" functions

[lacygoill]

Describe the bug

No tag is generated for Vim9 :def functions.

To Reproduce

Run these shell commands:

mkdir -p /tmp/vim_plugin \
&& cd /tmp/vim_plugin \
&& cat <<'EOF' >foo.vim
    fu Legacy()
        echo 'legacy function'
    endfu
    def Vim9Function()
        echo 'Vim9 function'
    enddef
EOF

ctags --options=NONE -R .

Here is the contents of the generated tags file:

!_TAG_FILE_FORMAT	2	/extended format; --format=1 will not append ;" to lines/
!_TAG_FILE_SORTED	1	/0=unsorted, 1=sorted, 2=foldcase/
!_TAG_OUTPUT_FILESEP	slash	/slash or backslash/
!_TAG_OUTPUT_MODE	u-ctags	/u-ctags or e-ctags/
!_TAG_PATTERN_LENGTH_LIMIT	96	/0 for no limit/
!_TAG_PROGRAM_AUTHOR	Universal Ctags Team	//
!_TAG_PROGRAM_NAME	Universal Ctags	/Derived from Exuberant Ctags/
!_TAG_PROGRAM_URL	https://ctags.io/	/official site/
!_TAG_PROGRAM_VERSION	0.0.0	/b4574f0a/
Legacy	foo.vim	/^    fu Legacy()$/;"	f

It does not contain a tag for the Vim9Function().

Expected behavior

I would expect this line to be present in the tags file:

Vim9Function	foo.vim	/^    def Vim9Function()$/;"	f

Environment

• ctags version:

  Universal Ctags 0.0.0(b4574f0a), Copyright (C) 2015 Universal Ctags Team
  Universal Ctags is derived from Exuberant Ctags.
  Exuberant Ctags 5.8, Copyright (C) 1996-2009 Darren Hiebert
    Compiled: Jul  8 2020, 09:30:25
    URL: https://ctags.io/
    Optional compiled features: +wildcards, +regex, +iconv, +option-directory, +xpath, +json, +interactive, +sandbox, +yaml, +packcc
  

• OS: Ubuntu 16.04.6 LTS

I built ctags locally after cloning the source code from the github repository, and making sure I was on the latest commit of the master branch.

Additional context

These new :def functions are documented on the vimhelp.org website.

[lacygoill]

Not sure whether this is a bug, but no tag is generated either for constants defined with the :const keyword.

---

I guess those tokens are too recent. I'll read the manpage to learn how to configure ctags(1) so that it parses them correctly.

[k-takata]

Universal ctags has a Vim script parser: https://github.com/universal-ctags/ctags/blob/master/parsers/vim.c
It doesn't support Vim9 script yet.
I think this should be discussed at the u-ctags repository, not here.

[lacygoill]

Universal ctags has a Vim script parser: https://github.com/universal-ctags/ctags/blob/master/parsers/vim.c

Oh, thank you very much for the pointer. I don't know C, but if it's not too difficult, maybe I'll try to submit a PR.

I think this should be discussed at the u-ctags repository, not here.

You're right, but I opened the issue on the u-ctags repository, not the Vim one.

[k-takata]

You're right, but I opened the issue on the u-ctags repository, not the Vim one.

Oh, I totally misunderstood if this is in the Vim repository.
(Because you reused the Vim repository's issue tempate.)