gqip for VHDL comments does not work

Question

After I set syntax=vhdl and set fo=tcq, running gqip on the following paragraph does not work as expected:

-- Lorem ipsum dolor sit amet, 
-- tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,
-- laboris nisi ut aliquip ex ea commodo

becomes:

-- Lorem ipsum dolor sit amet, -- tempor incididunt ut labore et dolore magna
aliqua. Ut enim ad minim veniam, -- laboris nisi ut aliquip ex ea commodo

Interestingly, using the same comment in a C++ (.cpp) file works as expected. This behavior shouldn't be related to any plugins since I tried with vim -u NONE; vim version is 7.4. Any ideas what could be wrong here?

Answer 1

You should tell Vim what a comment is using:

:set comments+=:--,b:--

Explanation:

• The comments option contains a comma separated list of strings that can start a comment line.
• :-- specifies the comment string (-- in that case) repeats at the start of each line.
• b:-- specifies a blank (<Space>, <Tab> or<EOL>) is required after --.
• See :help format-comments for details.

I see you typed :set syntax=vhdl manually. If this script is put in the .vimrc file, Vim will set this option for you whenever you enter :set syntax=vhdl:

augroup vhdlsyntax
   autocmd!
   autocmd Syntax vhdl 
      \ set formatoptions=tcq
      \     comments+=:--,b:--
augroup END

On the other hand, Vim actually can identify when a .vhdl file is been edited, but for some reason these options aren't (at least in this case) properly set in $VIMRUNTIME/ftplugin/vhdl.vim. However you can fix this issue by adding the FileType event to the previous script, like this:

augroup vhdlsyntax
   autocmd!
   autocmd FileType,Syntax vhdl 
      \ set formatoptions=tcq
      \     comments+=:--,b:--
augroup END