If you use an editor which is "tags"-aware, such as vim or emacs, you can take advantage of Exuberant Ctags' ability to define a custom language.

On Linux machine, create a file "~/.ctags" and add to it:

--langdef=reva
--langmap=reva:.f
--regex-reva=/^\s*:\s+([^ ]+)/\1/d,definition/

Windows users should consult the ctags documentation for how to accomplish the same thing.