Grep pattern from files

[michael-franzese]

Have written the following function to search for strings in
org and texi files

I call it this way

grepot num pattern dir

grepot ()
  { grep --include="*.org" --include="*.texi" -hir -C "$1" "$2" "$3"; }

But now I would like to extend it so I can include other file types
such as emacs-lisp files.

But I need some ideas on implementation as I think that my function
does have some serious limitiations.