[groff] 21/24: [tmac]: Revise "fallback" character definitions.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit fa1553c33ecfe925cc0c0eac41a30903ae040987
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Mon Dec 26 12:44:32 2022 -0600

    [tmac]: Revise "fallback" character definitions.
    
    ...in several respects for Unicode characters from General Punctuation
    block.
    
    * tmac/fallbacks.tmac: Comment out fallbacks for U+200B, U+2010, U+2011,
      and U+201[89CD], due to ineffectuality or apparent groff bugs.
      Redefine U+2012 fallback to include hair space (\^) around synthetic
      figure dash.  Redefine U+2016 to use `\[ba]` special characters
      instead of ordinary `|` characters to dodge possible character
      translations by user.
    
    Fixes part of <https://savannah.gnu.org/bugs/?63354>.  Thanks to Dave
    Kemper for the (multifarious) discussion.
---
 ChangeLog           | 15 +++++++++++++++
 tmac/fallbacks.tmac | 22 +++++++++++++---------
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 2eb82cc7d..1ed6de1fd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2022-12-26  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       [tmac]: Revise "fallback" character definitions in several
+       respects for Unicode characters from General Punctuation block.
+
+       * tmac/fallbacks.tmac: Comment out fallbacks for U+200B, U+2010,
+       U+2011, and U+201[89CD], due to ineffectuality or apparent groff
+       bugs.  Redefine U+2012 fallback to include hair space (\^)
+       around synthetic figure dash.  Redefine U+2016 to use `\[ba]`
+       special characters instead of ordinary `|` characters to dodge
+       possible character translations by user.
+
+       Fixes part of <https://savannah.gnu.org/bugs/?63354>.  Thanks to
+       Dave Kemper for the (multifarious) discussion.
+
 2022-12-25  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * doc/groff.texi (Invoking groff, Built-in Registers):
diff --git a/tmac/fallbacks.tmac b/tmac/fallbacks.tmac
index aee549d81..31f27e4eb 100644
--- a/tmac/fallbacks.tmac
+++ b/tmac/fallbacks.tmac
@@ -161,23 +161,27 @@
 .fchar \[u2008] \^\" puncutation space
 .fchar \[u2009] \|\" thin space
 .fchar \[u200A] \^\" hair space
-.fchar \[u200B] \h'0'\" zero-width space
-.fchar \[u2010] -\:\" hyphen
-.fchar \[u2011] -\" non-breaking hyphen (won't break w/o .hcode or \:)
+.\" Mapping U+200B awaits resolution of Savannah #58958.
+.\"fchar \[u200B] \h'0'\" zero-width space
+.\" \[u2010] is always defined thanks to uniglyph.cpp.
+.\"fchar \[u2010] -\:\" hyphen
+.\" Mapping U+2011 awaits resolution of Savannah #63354.
+.\"fchar \[u2011] -\" non-breaking hyphen (won't break w/o .hcode or \:)
 .ie \n[fallbacks*troff-mode] \
-.  fchar \[u2012] \v'-.3m'\l'\w"\0"u\[ru]'\v'+.3m'\" figure dash
+.  fchar \[u2012] \^\v'-.3m'\l'\w"\0"u'\v'+.3m'\^\" figure dash
 .el \
 .  fchar \[u2012] \-
 .fchar \[u2013] \[en]\" en dash
 .fchar \[u2014] \[em]\" em dash
 .fchar \[u2015] \[em]\" horizontal bar (quotation dash)
-.fchar \[u2016] ||\" double vertical line (matrix norm)
+.fchar \[u2016] \[ba]\[ba]\" double vertical line (matrix norm)
 .if \n[fallbacks*troff-mode] \
 .  fchar \[u2017] \Z'\[ul]'\v'+.1m'\[ul]\v'-.1m'\" double low line
-.fchar \[u2018] \[oq]\" left single quotation mark
-.fchar \[u2019] \[cq]\" right single quotation mark
-.fchar \[u201C] \[lq]\" left double quotation mark
-.fchar \[u201D] \[rq]\" right double quotation mark
+.\" Mapping U+201[89CD] awaits resolution of Savannah #59932.
+.\"fchar \[u2018] \[oq]\" left single quotation mark
+.\"fchar \[u2019] \[cq]\" right single quotation mark
+.\"fchar \[u201C] \[lq]\" left double quotation mark
+.\"fchar \[u201D] \[rq]\" right double quotation mark
 .\" XXX: The next two are troublesome; see Savannah #63332.
 .\"fchar \[u2020] \[dg]\" dagger
 .\"fchar \[u2021] \[dd]\" double dagger