Update of bug #67380 (group groff):
Status: None => Need Info
Assigned to: gbranden => barx
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Follow-up Comment #19:
[comment #15 comment #15:]
> This ticket covers a lot of things:
> * Clarifying the documentation:
> ** of groff's .fl request
> ** of the newly added .ab sentence, to note that only a break is needed to
> flush output
> ** that groff differs from AT&T troff in that a break always flushes
[snip]
> The original Summary was addressed in July (comment #1). Since this is still
> a documentation ticket, I think its scope should be limited to the
> documentation items above. Updating Summary.
Are these now accomplished?
> * Clarifying the documentation:
> ** of groff's .fl request
_doc/groff.texi.in_:
@Defreq {fl, }
@cindex flush pending output line (@code{fl})
@cindex output line, flush pending (@code{fl})
@cindex pending output line, flush (@code{fl})
@cindex interactive use of GNU @command{troff}
@cindex @command{gtroff}, interactive use of
@cindex @command{troff}, GNU, interactive use of
Break the line and flush any pending output line immediately.
The effect is the same as the
@code{br}
request unless the no-break control character is used;
@samp{'br}
does nothing,
whereas
@samp{'fl}
writes the pending output line
without further updating the drawing position.
However,
the @emph{reported} horizontal drawing position is still
reckoned from the start of the input line.
@Example
foo \n(hp
bar \c
'fl
\n(hp baz \n(hp
@result{} foo 96 bar 0 baz 144
@endExample
The timing of a flush is most easily perceived in GNU @command{troff}'s
device-independent output.
Use of
@samp{'fl}
may be desirable immediately prior to an
@code{ab}
request
when troubleshooting a document or macro definition line by line,
because a significant number of formatting operations
can accumulate on a partially collected output line,
misleading you about ``where'' the abort ``really'' took place.
Historically, @code{fl} was used with @code{rd} to produce interactive
@command{nroff} documents. GNU @command{troff} does not easily support
that mode of operation, because its output for terminals is first
prepared in device-independent format, which @command{grotty} renders a
page at a time.
@endDefreq
> ** of the newly added .ab sentence, to note that only a break is needed to
> flush output
+verbatim+
@Defreq {ab, [@Var{terminal-message}]}
@cindex abort (@code{ab})
Write any
@var{terminal-message}
to the standard error stream
(like
@code{tm})
and then abort GNU
@command{troff}; @c GNU
that is,
stop processing and terminate with a failure status.
Aborting does not flush a partially collected line,
a potentially significant fact if you're using
@code{ab}
to ``bisect'' a troublesome document or macro definition;
see the
@code{fl}
request below.
@endDefreq
> ** that groff differs from AT&T troff in that a break always flushes
I guess this isn't documented yet. So I'll do that.
Let me know if you concur that the other two issues are addressed.
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