[TUHS] Rivers, the ragged right, and BCPL roff (was: Spooky action at a distance in line adjustment...sometimes)

Doug McIlroy doug at cs.dartmouth.edu
Sun Jul 1 12:23:57 AEST 2018

> I was poking around on the Unix v7 man page archive the other day, and
> discovered to my delight that BCPL roff's request list was documented
> there. 

Yes, it's the same spec, though reimplementated; there was no BCPL
compiler for the PDP-11.

> Unfortunately, it was marked up in...BCPL roff embedded within
> a man page, which hopelessly confused groff.   

I edited the v7 manual and I believe I proofread every man page. How
could I have overlooked the misbehavior of the .li request*, which was
even then not in the reference manual's list of n/troff requests? On
closer examination, .li does appear in a condensed alphabetical list of
requests--and it appears in the source. But if Joe never described it,
it's no surprise that groff dropped it. It is totally unnecessary--a
bit of special pleading rendered obsolete by Joe's elegant invention
of \&.


* .li causes the next line to be read literally, even if it begins
with a dot.

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