Actually, you would use an ftplugin or autocmd to :set keywordprg=ri only when ft=ruby, which is what the ruby.vim files do. In fact, they are already part of

Actually, you would use an ftplugin or autocmd to :set keywordprg=ri only when ft=ruby, which is what the ruby.vim files do. In fact, they are already part of the standard runtime files distribution.