> If you run the example given for the .ad request in the groff info
> manual:
>
> text
> .ad r
> .nr ad \n[.j]
> text
> .ad c
> text
> .na
> text
> .ad \" back to centering
> text
> .ad \n[ad] \" back to right justifying
>
> you'll find it doesn't actually work, which seems to be because .ad
> does not produce a break. Adding a .br after every one of the
> "text" lines makes it do what's advertised.
You are right, thanks for noticing. I'll fix that.
> What I'm not understanding, though, is the behavior in a much simpler
> case:
>
> text
> .br
> .ad r
> text
> .br
> .ad \" should go back to the default....
> but doesn't seem to
> .br
>
> The second .ad, made without an argument, should return groff to the
> mode it was in before the first .ad call; in the case, the default,
> 'b' mode. Instead, the last line is output still in 'r' mode.
You've missed a paragraph in the documentation:
With no argument, `gtroff' adjusts lines in the same way it did
before adjusting was deactivated (with a call to `na', for
example).
In other words, `.ad XXX' stores `XXX' in the \[.j] register, and
emitting `.ad' without argument is the same as `.ad \[.j]', simply
re-using the stored value in \[.j]. This is different to other
requests which kind-of `pop' values from a stack if no arguments are
present.
Werner
