Re: [Groff] Conditional problem: "!" operator after "&"

[Larry Kollar]

Werner LEMBERG wrote:

>>     5  .if \n[NCS]&!\n[SIP] .nop NCS only.
>> 
>> test.t:5: warning: numeric expression expected (got `!')
> 
> I suspect that for backwards compatibility with AT&T troff only a
> `leading' exclamation mark – this is, at the very beginning of an
> expression within `.if', `.ie', or `.while' – is allowed.  You have to
> split up the compound expressions into simpler ones, see below.
> 
> Can you suggest a fix to groff.texinfo to document this better?

I'll try to work something up. Meanwhile, is this something that would break 
AT&T troff if groff were to do it right?

If I had the time & skill, I'd code up a .case request.

        Larry