Implement new number register `.br' which is set to 1 if a macro has

been called as .foo and to 0 if called as 'bar.  This is useful for
-mtrace so that requests can be reliably traced too.

* src/roff/troff/input.cpp (input_iterator): Add virtual function
`get_break_flag'.
(macro_iterator): Add `with_break' member and `get_break_flag'
function.
Update constructors.
(input_stack): Add function `get_break_flag'.
(break_flag_reg): New number register class.
(input_init_requests): Register `.br'.

* src/roff/troff/TODO: Updated.

* tmac/trace.tmac: s/!!sp/!!!sp/.
Modify definitions of `de', `de1', `am', and `am1' to use \n[.br].

* docs/groff.texinfo, man/groff.man, man/groff_diff.man, NEWS:
Document it.

1 files changed, 25 insertions, 0 deletions

diff --git a/doc/groff.texinfo b/doc/groff.texinfo
index 907c9a59..d1f7ee79 100644
--- a/doc/groff.texinfo
+++ b/doc/groff.texinfo
@@ -5438,6 +5438,29 @@ In most cases the period is used as a control character.  Several
 requests cause a break implicitly; using the single quote control
 character prevents this.
 
+@Defreg {.br}
+A read-only number register which is set to@tie{}1 if a macro is called
+with the normal control character (as defined with the @code{cc}
+request), and set to@tie{}0 otherwise.
+
+@cindex modifying requests
+@cindex requests, modifying
+This allows to reliably modify requests.
+
+@Example
+.als bp*orig bp
+.de bp
+.  tm before bp
+.  ie \\n[.br] .bp*orig
+.  el 'bp*orig
+.  tm after bp
+..
+@endExample
+
+Using this register outside of a macro makes no sense (it always returns
+zero in such cases).
+@endDefreg
+
 @menu
 * Request and Macro Arguments::
 @end menu
@@ -7620,6 +7643,8 @@ no-break control character is associated with the current environment
 (@pxref{Environments}).
 @endDefreq
 
+@xref{Requests}.
+
 @Defreq {eo, }
 @cindex disabling @code{\} (@code{eo})
 @cindex @code{\}, disabling (@code{eo})