Question

I am attempting to write a syntax file for Vim.

One of the lines of code reads

syn match constant "\**\*"

while one of many other lines reads

syn keyword aiOperators up-build

The code for highlighting is the following:

hi constant gui=bold
hi aiOperators guifg=green

However, the result of the above is that only the following is highlighted:

• The asterisks of every constant, but not the characters between them.
• Characters up until the first hyphen of aiOperators.

What seems to be the issue?

Answer 1

The regular expression for your constant specifies a literal asterisk, zero or more times, followed by a literal asterisk. If you intend to match characters delimited by asterisks, you need something like \*\w\+\*: a literal asterisk, followed by one or more word characters, followed by a literal asterisk.

The :syn keyword only works for keyword characters; by default, the hyphen is not included, so the match stops there. If, for your filetype, the hyphen belongs to the set of keyword characters, use

:setlocal iskeyword+=-

This should not be placed into the syntax file itself, but into ~/.vim/ftplugin/myfiletype.vim. Otherwise, use :syn match.