[groff] 06/09: [tbl] Save and restore tab stops.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit d0e03cf610aa4e7bb9a549535bcce8ba5f8b9435
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Tue Oct 20 23:39:06 2020 +1100

    [tbl] Save and restore tab stops.
    
    * src/preproc/tbl/table.cpp (table::init_output): Save the value of
      \n[.tabs] when starting a table.  In the reset macro, restore the
      saved value.
    
    Based on a patch by Bjarni Ingi Gislason (tweaked to use a more
    normative preprocessor symbol; "REG"s aren't "NAME"s).
    
    Fixes <https://savannah.gnu.org/bugs/index.php?42978>.
---
 ChangeLog                 | 14 ++++++++++++++
 src/preproc/tbl/table.cpp |  3 +++
 2 files changed, 17 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 1a86a6e..ce0b7ea 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,19 @@
 2020-10-20  G. Branden Robinson <g.branden.robinson@gmail.com>
 
+       * src/preproc/tbl/table.cpp (table::init_output): Save the value
+       of \n[.tabs] when starting a table.  In the reset macro, restore
+       the saved value.
+
+       Based on a patch by Bjarni Ingi Gislason (tweaked to use a more
+       normative preprocessor symbol; "REG"s aren't "NAME"s).
+
+       * src/preproc/tbl/tests/save-and-restore-tab-stops.sh: Test it.
+       * src/preproc/tbl/tbl.am (tbl_TESTS): Run test.
+
+       Fixes <https://savannah.gnu.org/bugs/index.php?42978>.
+
+2020-10-20  G. Branden Robinson <g.branden.robinson@gmail.com>
+
        * src/roff/nroff/nroff.sh: Recognize -E option and pass it
        through to troff.  Document it in usage message.
        * src/roff/nroff/nroff.1.man: Document new -E option.
diff --git a/src/preproc/tbl/table.cpp b/src/preproc/tbl/table.cpp
index dd8fcac..8dbd4bc 100644
--- a/src/preproc/tbl/table.cpp
+++ b/src/preproc/tbl/table.cpp
@@ -48,6 +48,7 @@ const int DEFAULT_COLUMN_SEPARATION = 3;
 #define SAVED_FILL_REG PREFIX "fll"
 #define SAVED_INDENT_REG PREFIX "ind"
 #define SAVED_CENTER_REG PREFIX "cent"
+#define SAVED_TABS_NAME PREFIX "tabs"
 #define TABLE_DIVERSION_NAME PREFIX "table"
 #define TABLE_DIVERSION_FLAG_REG PREFIX "tflag"
 #define TABLE_KEEP_MACRO_NAME PREFIX "tkeep"
@@ -1774,11 +1775,13 @@ void table::init_output()
         ".ie \\n[.u] .fi\n"
         ".el .nf\n"
         ".ce \\n[.ce]\n"
+        ".ta \\\\*[" SAVED_TABS_NAME "]\n"
         "..\n"
         ".nr " SAVED_INDENT_REG " \\n[.i]\n"
         ".nr " SAVED_FONT_REG " \\n[.f]\n"
         ".nr " SAVED_SIZE_REG " \\n[.s]\n"
         ".nr " SAVED_FILL_REG " \\n[.u]\n"
+        ".ds " SAVED_TABS_NAME " \\n[.tabs]\n"
         ".nr T. 0\n"
         ".nr " CURRENT_ROW_REG " 0-1\n"
         ".nr " LAST_PASSED_ROW_REG " 0-1\n"