First install ctags if you don't have it already.
brew install ctags
Copy the ctags file in the repo to $HOME/.ctags
cp ctags $HOME/.ctags
Install tagbar (for vim) from https://github.com/majutsushi/tagbar
Then add the below to your vimrc file
nmap <F8> :TagbarToggle<CR>
let g:tagbar_type_pig = {
\ 'ctagstype' : 'pig',
\ 'kinds' : [
\ 'a:Alias',
\ 's:Set',
\ 'r:REGISTER',
\ 'd:DEFINE'
\]
\}