Re: [Groff] Flexible whitespace, columns, and the .h register

[Ralph Corderoy]

Hi Peter,

> On re-reading cstr54, I see .h is defined as the "Text baseline
> high-water mark on current page or diversion," which is somewhat
> ambiguous

How so?

> and diversions aren't mentioned in the info docs at all, which state:
> "The 'high-water mark' on the current page.  It corresponds to the
> text baseline of the lowest line on the page."

But it is in the Diversions section.

    5.25 Diversions
    ===============

    ...

     -- Register: \n[.h]
         The "high-water mark" on the current page.  It corresponds to the
         text baseline of the lowest line on the page.  This is a read-only
         register.

              .tm .h==\n[.h], nl==\n[nl]
                  => .h==0, nl==-1
              This is a test.
              .br
              .sp 2
              .tm .h==\n[.h], nl==\n[nl]
                  => .h==40, nl==120

         As can be seen in the previous example, empty lines are not
         considered in the return value of the '.h' register.

> The issue doesn't affect my problem, but should we consider amending
> the info docs entry?  "...corresponds to the text baseline of the
> lowest line on the page, or, if in a diversion, of the lowest text
> baseline in the diversion, measured from the start of the
> diversion."  Words to that effect, anyway.

I think the info doc should mention diversion in "...on the page".  Is
the measured bit needed?  Isn't that the origin of all diversions
measurements?

Does .h being diversion-specific make it easy for you to work around .h
being read-only?  Is there a problem with making it writable?  Are there
other things that it might be nice to be able to reset with some new
command as if we were hovering above the start of this virgin page?

-- 
Cheers, Ralph.
https://plus.google.com/+RalphCorderoy