Re: [Groff] LaTeX-style `emph'

[Robert D. Goulding]

On Wed, 4 Dec 2002, Werner LEMBERG wrote:

> > Has anyone come up with a good way to implement a LaTeX-style emph -
> > i.e., switches to italic font if the current font is roman, but
> > roman if it is italic.  I thought of the following:
> >
> > .ds emph \R'nF (3-\\n(.f)'\f[\\n(nF]\\$1\fP
> >
> What about this:
>
>   .ds emphTR  TI
>   .ds emphTI  TR
>   .ds emphTB  TBI
>   .ds emphTBI TB
>   .
>   .ds emphHR  HI
>   .ds emphHI  HR
>   .ds emphHB  HBI
>   .ds emphHBI HB
>   .
>   .ds Emph \E*[emph]
>   .ds emph \f[\\*[emph\\n[.fn]]]
>   .
...
>
>
> The following lengthy solution works for all families.  In a macro
> package, the first four lines of the `emph' string should be called
> while selecting the font family.
>
>   .ds emph \
>   \f[R]\R'tmp \\n[.f]'\f[]\
>   \f[I]\R'emph\\n[tmp] \\n[.f]'\R'emph\\n[.f] \\n[tmp]'\f[]\
>   \f[B]\R'tmp \\n[.f]'\f[]\
>   \f[BI]\R'emph\\n[tmp] \\n[.f]'\R'emph\\n[.f] \\n[tmp]'\f[]\
>   \f[\\n[emph\\n[.f]]]
>
I'm amazed - thanks very much for coming up with this solution.  I'll test
it out with refer - it will be very useful for book titles within book
titles etc.
 >
> > (BTW, as I play around with inline macros like this, I keep thinking
> > that groff needs some kind of inline conditional - is this
> > possible?)
>
> Make some syntax suggestions.

I was thinking about something along the lines of
\i'test''iftrue''iffalse'.

Perhaps there could be a short form using the standard conditional
operators. E.g., \it'iftroff''ifnottroff'

But I have no idea whether this is feasible/desirable.

Robert.