Re: [Groff] surprise, surprise

[Werner LEMBERG]

> > PS.  Who're you calling young?
> 
> Well, I dare not intervene on that last point.

Aah, I've missed this post scriptum!  With `young' I consider all
groff users who have never used AT&T troff or an equal commercial
variant.

>    So maybe there should be two programs: GNU troff, and groff.  GNU
>    troff would be the GNU implementation of UNIX troff, and could be
>    used without soul-searching by people who still have old troff
>    files which need formatting.

At least *I* won't implement such a thing.  As far as I can see, the
implementation differences between troff and groff (using -C) are
marginal in most cases and affect highly obscure features no user
should really rely on.

>  3. And now for the question. In the above mentioned "man troff"
>    section on Incompatibilities, only the first paragraph explicitly
>    states what the effect of "-C" is, namely to disallow long names
>    (and enable interpretation of ".abcde" as ".ab cde"; and this is
>    all that is stated under ".cp" as well).

As mentioned in a previous mail, the other main thing is the
preservation of the input level -- I'll add this soon to the docs.

>    For all the other incompatibilities listed under
>    "Incompatibilities", (".ps 10u", differences between unformatted
>    input characters and formatted output characters, etc) it is not
>    explicitly stated whether these are still incompatibilities in
>    compatibility mode.

They are still incompatibilities.

>   So: Are there incompatibilities between "groff -C" and "UNIX
>   troff" and, if so, which are they? I have had so very little need
>   to use groff in "compatibility" mode that I have never done the
>   experimentation needed to establish any of this.

Everything mentioned in the `Incompatibilities' section falls into
this category.  Clark seems to have made a clear distinction between
syntactical issues (controlled by -C) on the input level, extentions
to the syntax, and typographical output.  The latter two can't be
switched off in compatibility mode.

> By the way: Plan-9 troff source presumably compiles to a truly
> compatible "UNIX troff"; at any rate the "Troff Users Manual" that
> goes with Plan-9 troff seems to be almost identical to the UNIX one.
> But I suppose that the Plan-9 "licence" is incompatible with GNU's
> GPL.

Since Plan-9's troff is freely available, the easiest solution is to
make it compile on platforms like Linux -- since the Plan-9 extensions
are surrounded by #ifdef statements, this shouldn't be too hard.  I
can imagine that providing an RPM or Debian package (with an
appropriate diff file) would be the right thing.

I must admit that I really don't care whether this `original troff' is
GPL'ed or not...


    Werner