font-lock regexp for complementary keywords

[Dieter Wilhelm]

Hi

I'd like to fontify Ansys keywords.  The solver accepts unique short
forms of the command keywords, the rest is ignored.  For example the
uniqe part of `/filname' is `/fil' and I'd like to fontify

/fil and
/filn and
/filna and
/filnam and
/filname and

as well.  The only idea I got so far is to do it in 5 separate
font-lock statements:

\\(/fil\\) 1 font-lock...
/fil\\(n\\) 1 fon...
/filn\\(a\\) 1 ...
/filna\\(m\\) 1 ...
/filnam\\(e\\) 1 ...

Very ugly and inefficient, isn't it?
Originally I thought that something like this

/fil\\(n\\|na\\|nam\\|name\\)

would work but rexexp-bulider doesn't show any matches for the
complementing alternatives.

-- 
    Best wishes

    H. Dieter Wilhelm
    Darmstadt, Germany