Completion system (filename prefixes)

[Haakon Riiser <hakonrk@xxxxxxxxxx>]

I have started writing a completion function for Vim, but there's
one feature I'd like to add that I can't figure out how to do.

In Vim, files starting with + needs to be prefixed with ./ or
Vim will believe it is a Vim command instead of a filename.
I know you can say

  -P ./

to _path_files to get the prefix for all files, but I would rather
that it was added only where it's needed.  By also saying

  -g '+*'

it will only apply to files starting with +, but now these files
are the only ones that are completed.  Any help is appreciated.

-- 
 Haakon