Better vim tag jump for working on SILE development

[ctrlcctrlv]

function LuaTag()  
    setlocal isk+=:
    setlocal isk+=.
    try
        exe "tag " . expand('<cword>')
    catch /E426/
        setlocal isk-=:
        setlocal isk-=.
        try
            exe "tag " . expand('<cword>')
        catch /E426/
            exe "tag package:" . expand('<cword>')
        endtry
    endtry
    setlocal isk-=:
    setlocal isk-=.
endfunction
au BufRead *.lua nnoremap <buffer> <C-]> :call LuaTag()<CR>

Before <C-]> would not work if pressed here:

But after!