[groff] 06/17: [docs]: Fix Savannah #63812.

[G. Branden Robinson]

gbranden pushed a commit to branch post-1.23.0
in repository groff.

commit 10f779d5485494fad0989fc7406edf6ab6497d34
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Sun Mar 5 03:10:48 2023 -0600

    [docs]: Fix Savannah #63812.
    
    * doc/groff.texi (Operators in Conditionals):
    * man/groff.7.in (Conditional expressions): Clarify how the output
      comparison operator is recognized.
    
    Fixes <https://savannah.gnu.org/bugs/?63812>.  Thanks to John Gardner
    for the report.
---
 ChangeLog       |  9 +++++++++
 doc/groff.texi  | 11 +++++++++++
 man/groff.7.man | 17 ++++++++++++++---
 3 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d88e97353..2a5b07f5d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 2023-03-07  G. Branden Robinson <g.branden.robinson@gmail.com>
 
+       * doc/groff.texi (Operators in Conditionals):
+       * man/groff.7.in (Conditional expressions): Clarify how the
+       output comparison operator is recognized.
+
+       Fixes <https://savannah.gnu.org/bugs/?63812>.  Thanks to John
+       Gardner for the report.
+
+2023-03-05  G. Branden Robinson <g.branden.robinson@gmail.com>
+
        [tbl]: Trivially refactor.  Rename variables and functions to
        use the term "rule" rather than "line".  The value of the term
        "rule" is that it is not confusable with "lines" of (text) input
diff --git a/doc/groff.texi b/doc/groff.texi
index 5c4af4fc9..7e300dbef 100644
--- a/doc/groff.texi
+++ b/doc/groff.texi
@@ -12571,8 +12571,19 @@ certain other @code{troff} 
implementations.@footnote{This refers to
 @code{vtroff}, a translator that would convert the C/A/T output from
 early-vintage @acronym{AT&T} @code{troff} to a form suitable for
 Versatec and Benson-Varian plotters.}
+@end table
+
+If the first argument to an @code{if}, @code{ie}, or @code{while}
+request begins with a non-alphanumeric character apart from @code{!}
+(see below); it performs an @slanted{output comparison test}.
+@footnote{Strictly, letters not otherwise recognized @emph{are} treated
+as output comparison delimiters.  For portability, it is wise to avoid
+using letters not in the list above; for example, Plan@tie{}9
+@code{troff} uses @samp{h} to test a mode it calls @code{htmlroff}, and
+GNU @code{troff} may provide additional operators in the future.}
 
 @cindex output comparison operator
+@table @code
 @item @code{'}@var{xxx}@code{'}@var{yyy}@code{'}
 True if formatting the comparands @var{xxx} and @var{yyy} produces the
 same output commands.  The delimiter need not be a neutral apostrophe:
diff --git a/man/groff.7.man b/man/groff.7.man
index 0d0539a98..e16ec458f 100644
--- a/man/groff.7.man
+++ b/man/groff.7.man
@@ -10,7 +10,7 @@ language reference
 .\" Legal Terms
 .\" ====================================================================
 .\"
-.\" Copyright (C) 2000-2018, 2020-2022 Free Software Foundation, Inc.
+.\" Copyright (C) 2000-2023 Free Software Foundation, Inc.
 .\"
 .\" This file is part of groff, the GNU roff type-setting system.
 .\"
@@ -2099,9 +2099,20 @@ T}
 .
 .
 .P
-The first of the above,
+If the first argument to an
+.BR .if ,
+.BR .ie ,
+or
+.B .while
+request begins with a non-alphanumeric character apart from
+.B !\&
+(see below);
+it performs an
+.I output comparison test.
+.
+Shown first in the table above,
 the
-.I "output comparison operator,"
+.I output comparison operator
 interpolates a true value if formatting its comparands
 .I s1
 and