> A personal false-identification hazard:
> in the court of groff I will be declared innocent if I call
> myself M. Douglas McIlroy,
> but will be sentenced if I call myself Mr. Douglas McIlroy,
Not sure what you mean here. Groff will treat both exactly the
same, it's TeX that will treat them differently (period after
lower-case letter = end of sentence, period following capital
letter = not end of sentence).
In groff it's much simpler: end of sentence is recognized as
period at end of line or period followed by two spaces.
(Ditto for question mark and exclamation mark.)
Excess spaces will be treated by groff as usual, i.e., just
copied as-is to the output.
Consider the attached example. The resulting text in nroff
with the exaggerated sentence space, and the number of spaces
in the output, are:
Output Number of spaces
------------------------------------------------------
M. Douglas McIlroy 1
Mr. Douglas McIlroy 1
M. Douglas McIlroy 7 = 1 + 6
Mr. Douglas McIlroy 7 = 1 + 6
M. Douglas McIlroy 7 = 2 - 1 + 6
Mr. Douglas McIlroy 7 = 2 - 1 + 6
M. Douglas McIlroy 9 = 4 - 1 + 6
Mr. Douglas McIlroy 9 = 4 - 1 + 6
M. Douglas McIlroy 2
Mr. Douglas McIlroy 2
M. Douglas McIlroy 4
Mr. Douglas McIlroy 4
The "roff" manpage suggests:
Start each sentence on a line of its own, for the spacing
after a dot is handled differently depending on whether it
terminates an abbreviation or a sentence. To distinguish
both cases, do a line break after each sentence.
(I guess what is actually meant is "should typographically be
handled differently", because groff has no way to automatically
recognize abbreviations.)
The recommendation is also useful (even when you're using TeX
or HTML or some other markup language that allows text reflow)
if you are keeping documents in a line-oriented version control
system, because it restricts the differences detected between
versions, in that it does not cause an entire paragraph to
become flagged as different if only one sentence is changed.
.\"
.\" --------------------------------------------
.\" Exaggerate sentence space in order to
.\" emphasize end-of-sentence in output:
.ss 12 72
.\" --------------------------------------------
.\" One space after period, followed by text,
.\" is treated as a normal space:
M. Douglas McIlroy
.br
Mr. Douglas McIlroy
.br
.\" --------------------------------------------
.\" A period at end of line is treated as
.\" end-of-sentence:
M.
Douglas
McIlroy
.br
Mr.
Douglas
McIlroy
.br
.\" --------------------------------------------
.\" A period followed by two spaces is
.\" treated as end-of-sentence:
M. Douglas McIlroy
.br
Mr. Douglas McIlroy
.br
.\" --------------------------------------------
.\" Any additional spaces are *added* to the
.\" sentence space:
M. Douglas McIlroy
.br
Mr. Douglas McIlroy
.br
.\" --------------------------------------------
.\" \& after the period disables end-of-sentence
.\" recognition; all spaces are copied to output:
M.\& Douglas McIlroy
.br
Mr.\& Douglas McIlroy
.br
M.\& Douglas McIlroy
.br
Mr.\& Douglas McIlroy
.br
