help syntax don't support help tags with unicode characters

[mildred]

Here is defined the syntax highlighting pattern for help tags:

neovim/runtime/syntax/help.vim

Lines 22 to 24 in 2f4647e

	syn match helpHyperTextJump "\\\@<!|[#-)!+-~]\+|" contains=helpBar
	syn match helpHyperTextEntry "\*[#-)!+-~]\+\*\s"he=e-1 contains=helpStar
	syn match helpHyperTextEntry "\*[#-)!+-~]\+\*$" contains=helpStar

This pattern doesn't match utf-8 unicode characters. More specifically, the [...+-~] matches the pure ASCII alphabet but not any alphabetic character beyond that. Specifying negative character class using [^ "*\t] instead of [#-)!+-~] would match all unicode charactes (and control characters, but those are not supposed to be present in text files except for tabs)

A ASCII table would show that out of the #-) range, and out of +-~ with the ! character excluded there are only control characters below 32, space , double quote", and the star *

[mildred]

Note that the :helptags commands already supports tags with unicode characters.

[mildred]

I am using this in my vimrc:

augroup vimrc_filetype_help
  au FileType help syn match helpHyperTextJump	"\\\@<!|[^ \þ!*]\+|" contains=helpBar
  au FileType help syn match helpHyperTextEntry	"\*[^ \t!*]\+\*\s"he=e-1 contains=helpStar
  au FileType help syn match helpHyperTextEntry	"\*[^ \t!*]\+\*$" contains=helpStar
augroup END

[justinmk]

We don't want to fork the Vim runtime plugins in most cases (especially syntax plugins), unless there's a very good reason. Because if Vim changes something in the same file, it takes time to figure out the differences.

Probably this change will be accepted at https://github.com/vim/vim, could you report it there?

[justinmk]

this was rejected at vim/vim#2213 , and we're not going to diverge here, since we merge Vim's runtime updates. And this can be overridden in one's vimrc as shown above.