Check your syntax files for configurable options
From Vim Tips Wiki
created November 29, 2007 · complexity basic · author Fritzophrenic · version 7.0
Many times, the default syntax file for a given file type leaves something to be desired. For example, perhaps you edit a lot of perl code, and wish that there was pre-defined syntax folding that you could use.
Before you decide to hack the syntax file, or create additions in your after/syntax directory, be sure to check to make sure your desired behavior doesn't already exist as a configurable option in the default syntax file.
A good starting point would be to look up the help page on the syntax file. For our example, use :help perl.vim. Here you can see that you can:
and perl.vim will define the folding for you! Alternatively, you could open perl.vim directly from your install directory under "syntax". There, you would see the following:
" The following parameters are available for tuning the " perl syntax highlighting, with defaults given: " ... " ... " unlet perl_fold " unlet perl_fold_blocks " ...
Regardless of how you find them, you can set values for these custom options in your vimrc, or in your own ftplugin directory, to run before the normal ftplugin for the filetype. See :help ftplugin.