Re: [Groff] strange if "..."..." behaviour

[Larry Jones]

Werner LEMBERG writes:
> 
> .ds xx \fR|\fP
> .ie "|"\*(xx" \
> .  tm true
> .el \
> .  tm false
> 
> Would you expect that the result is `true'?  I didn't.

Yes.

> The original troff manual says:
> 
>   ... if the strings compare identically (including motions and
>   character size and font), _anything_ is accepted as input ...
> 
> I would interpret this that the comparison is done by a simple
> strcmp(), and not interpreting the strings.  Can someone please check
> this with an original AT&T troff?

No, what it's saying is that the resulting motions, character sizes, and
fonts have to match, not that the individual motion, size and font
requests have to match.  In this case ``|'' and ``\fR|\fP'' both result
in a roman ``|'' character with the same point size and at the same
location on the page, so the strings are equal.  If you added a ``.ft
I'' before the ``.ie'', then it's false because ``|'' produces an italic
``|'' rather than a roman one.  AT&T troff works exactly the same way.

-Larry Jones

Any game without push-ups, hits, burns or noogies is a sissy game. -- Calvin