Re: long nroff tables

[James K. Lowden]

On Wed, 20 Jan 2021 18:00:39 +0100
Oliver Corff <oliver.corff@email.de> wrote:

> try this:
> 
> TS H

Hi Oliver, 

Thanks for the suggestion.  I'm still stuck for the "right" way, but it
turns out lengthening the logical page does the trick: 

        .pl 100i

I didn't find a way to avoid diving down into troff requests.  

Here's my input:  

.ll +6.5i
.TS H
box;
LBLBLB
N L L .
T{
id
T}      T{
author
T}      T{
body
T}
_
.TH
...

The input comes from SQL; my program just wraps it in tbl and sends
it off to nroff for display. The data for every cell is wrapped in 

        T{...
        T} 

to let groff format it. 

With the particular output in question, -mdoc (or no macro set) fails
spectacularly: 

$ nroff -t -mdoc R | cat -s | wc -l
error: page 2: table will not fit on one page; use .TS H/.TH with a
supporting macro package
       1 

That last "1" is wc(1) reporting one line of output :-(  

With -mdoc, I get pagination, and a better diagnostic: 

$ nroff -t -ms R | cat -s | wc -l
R:18: warning [p 1, 1.0i, div `3tbd1,2', 0.5i]: cannot adjust line
R:18: warning [p 1, 1.0i, div `3tbd1,2', 2.0i]: cannot adjust line
R:18: warning [p 1, 1.0i, div `3tbd1,2', 3.8i]: cannot adjust line
R:24: warning [p 1, 1.0i, div `3tbd2,2', 2.2i]: cannot adjust line
R:24: warning [p 1, 1.0i, div `3tbd2,2', 6.0i]: cannot adjust line
R:26: warning [p 1, 1.0i, div `3tbd2,2', 9.3i]: cannot adjust line
R:47: warning [p 1, 1.0i, div `3tbd5,2', 1.5i]: cannot adjust line
R:47: warning [p 1, 1.0i, div `3tbd5,2', 1.8i]: cannot adjust line
R:52: warning [p 1, 1.0i, div `3tbd6,2', 0.7i]: cannot adjust line
R:57: warning [p 1, 1.0i, div `3tbd7,2', 1.5i]: cannot adjust line
R:59: warning [p 1, 1.0i, div `3tbd7,2', 3.2i]: cannot adjust line
warning: page 2: table text block will not fit on one page
     180

That warning suggested something problematic with the data.  The "body"
column is the wide one, and adjusting the header

        N L Lw(50) .

"solves" the problem completely, but only by reducing the output to 66
lines. If I use 

        N L Lw(30) .

It prints OK in -ms (except paginated), but in -mdoc (or none), I get: 

$ nroff -t R -mdoc | cat -s | less
error: page 2: table will not fit on one page; use .TS H/.TH with a
supporting macro package

I guess that's because -mdoc does not support .TS H?  

I have run across this elsewhere, converting documentation to mdoc.
It's not unusual for formal documentation to have tables that run on
for many pages.  It feels like a gap in mdoc.  

I'm starting to think that if I want long tables displayed in mdoc in
nroff, the right way is to roll up my sleeves and figure out how to
implement the macro, and be sensititive to the logical page length.  

But for my immediate purposes, I can use 100 inch logical pages
conditional to running in nroff.  

--jkl