[groff] 31/62: [ms]: Fix Savannah #64013.

[G. Branden Robinson]

gbranden pushed a commit to branch branden-2023-04-20
in repository groff.

commit 5efa1cece9a9ae1069a7523fa57ab7dd8cc91704
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Fri Apr 7 20:22:46 2023 -0500

    [ms]: Fix Savannah #64013.
    
    * tmac/s.tmac (@EQ): Revise argument handling.  If there is only one
      argument and it is not a recognized alignment, warn and treat it as an
      equation label.  If there are two arguments but the first is not a
      recognized alignment, throw a warning diagnostic (but still use
      default alignment with the second argument as label).  An explicitly
      empty first argument is synonymous with "C".
    
    Fixes <https://savannah.gnu.org/bugs/?64013>.
    
    Also tested with:
    
    .LP
    .EQ "" (1)
    x + y = z
    .EN
    .EQ (2) \" expect warning
    pq = 0
    .EN
    .EQ R (3) \" expect warning
    ab = 1
    .EN
    .EQ
    E = mc sup 2
    .EN
---
 ChangeLog   | 14 ++++++++++++++
 tmac/s.tmac | 25 +++++++++++++++++++------
 2 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 05d8ca18a..b400e931c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2023-04-07  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       [ms]: Fix Savannah #64013.
+
+       * tmac/s.tmac (@EQ): Revise argument handling.  If there is only
+       one argument and it is not a recognized alignment, warn and
+       treat it as an equation label.  If there are two arguments but
+       the first is not a recognized alignment, throw a warning
+       diagnostic (but still use default alignment with the second
+       argument as label).  An explicitly empty first argument is
+       synonymous with "C".
+
+       Fixes <https://savannah.gnu.org/bugs/?64013>.
+
 2023-04-07  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        [ms]: Regression-test Savannah #64013.
diff --git a/tmac/s.tmac b/tmac/s.tmac
index 236594f89..dad2d6371 100644
--- a/tmac/s.tmac
+++ b/tmac/s.tmac
@@ -1885,14 +1885,27 @@ along with this program.  If not, see 
<http://www.gnu.org/licenses/>.
 .if \\n[tbl@within-table] \
 .      @error .EQ is not allowed within a .TS/.TE table
 .br
+.nr eqn*type -1
 .ds eqn*num "\\$2
-.ie '\\$1'L' .nr eqn*type 0
-.el \{\
-.      ie '\\$1'I' .nr eqn*type 1
-.      el \{\
-.              nr eqn*type 2
-.              if !'\\$1'C' .ds eqn*num "\\$1
+.if '\\$1'L' .nr eqn*type 0
+.if '\\$1'I' .nr eqn*type 1
+.if '\\$1'C' .nr eqn*type 2
+.if (\\n[eqn*type] < 0) \{\
+.      ds eqn*msg .EQ: unrecognized alignment '\\$1';
+.      ie (\\n[.$] = 1) \{\
+.              if !'\\$1'' \{\
+.                      as eqn*msg " assuming it is an equation label
+.                      @warning \\*[eqn*msg]
+.                      ds eqn*num "\\$1
+.              \}
+.      \}
+.      el .if (\\n[.$] > 1) \{\
+.              if !'\\$1'' \{\
+.                      as eqn*msg " centering equation
+.                      @warning \\*[eqn*msg]
+.              \}
 .      \}
+.      rm eqn*msg
 .\}
 .di eqn*div
 .in 0