问题
In vim, I am editing a file of filetype "markdown", but which contains latex math expressions such as $x_i$. Vim's syntax highlighting for markdown thinks the pattern *_* (letter-underscore-letter) is an error, and highlights the underscore in such patterns bright red. I would like to turn this off by adding a line to my .vimrc:
autocmd BufEnter *.Rmd "Dear vim, please don't highlight the pattern *_*"
What is the appropriate command to do that? Is it possible at all to do that in .vimrc, without editing a syntax file?
Note: I want to keep the markdown syntax highlighting in general, only turn off that particular feature.
回答1:
You have to modify the Markdown syntax for that. One way would be to remove the parsing of the error:
:syn clear markdownError
But that would cause the other syntax rules to start an italic section on that _ char. Better just clear the error highlighting with:
:hi link markdownError Normal
To maintain the general error highlighting, but only define exceptions for the special $x_i$ string, define an overriding syntax group; luckily, this is easy because no existing syntax is there:
:syn match markdownIgnore "\$x_i\$"
(Adapt the regular expression to match all possible math expressions.)
This needs to be put into ~/.vim/after/syntax/markdown.vim to be executed after the original syntax script.
回答2:
If you want to remove _ from the markdown error pattern, you can redefine it. In my case I want to turn off error notifications of underscores in a word as I put a lot of URLs in my documents.
There's a line that defines the error pattern inside syntax/markdown.vim file
" Original error pattern
syn match markdownError "\w\@<=_\w\@="
Remove the _ from the pattern and add that to ~/.vim/after/syntax/markdown.vim.
" New error pattern without the underscore
syn match markdownError "\w\@<=\w\@="
来源：https://stackoverflow.com/questions/19137601/turn-off-highlighting-a-certain-pattern-in-vim