[groff] 103/115: [eqn]: Fix Savannah #64216.

[G. Branden Robinson]

gbranden pushed a commit to branch branden-2022-06-01
in repository groff.

commit 53a21b9272b117ddf20d09264e8631cfb9ecb231
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Fri May 19 00:52:28 2023 -0500

    [eqn]: Fix Savannah #64216.
    
    [eqn]: Implement tunable "half_space" and "full_space" parameters.  They
    default to the same widths as "thin_space" and "thick_space",
    respectively, but control the widths of the '^' and '~' input tokens.
    
    * src/preproc/eqn/box.cpp: Add globals `half_space`, `full_space`.
    
      (struct S): Recognize "half_space" and "full_space" as parameters to
      the "set" primitive, and map them to the globals.
    
      (half_space_box::output): Format the half space width.
    
      (full_space_box::output): Format the full space width.
    
      (full_space_box::output, thick_space_box::output): Drop workaround for
      Firefox 1.5 MathML bug (November 2005).  Emit "&ThickSpace;" entity
      instead of "&ensp;".
    
    * src/preproc/eqn/eqn.1.man (Customization): Document feature.
    
    * NEWS: Add item.
    
    Fixes <https://savannah.gnu.org/bugs/?64216>.  Thanks to Doug McIlroy
    for the report and Damian McGuckin for the discussion.
---
 ChangeLog                 | 24 ++++++++++++++++++++++++
 NEWS                      |  6 ++++++
 src/preproc/eqn/box.cpp   | 14 ++++++++------
 src/preproc/eqn/eqn.1.man | 18 ++++++++++++------
 src/preproc/eqn/pbox.h    |  9 ++++++++-
 5 files changed, 58 insertions(+), 13 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 195896e03..85558621f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,27 @@
+2023-05-19  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       [eqn]: Implement tunable "half_space" and "full_space"
+       parameters.  They default to the same widths as "thin_space" and
+       "thick_space", respectively, but control the widths of the '^'
+       and '~' input tokens.
+
+       * src/preproc/eqn/box.cpp: Add globals `half_space`,
+       `full_space`.
+       (struct S): Recognize "half_space" and "full_space" as
+       parameters to the "set" primitive, and map them to the globals.
+       (half_space_box::output): Format the half space width.
+       (full_space_box::output): Format the full space width.
+       (full_space_box::output, thick_space_box::output): Drop
+       workaround for Firefox 1.5 MathML bug (November 2005).  Emit
+       "&ThickSpace;" entity instead of "&ensp;".
+
+       * src/preproc/eqn/eqn.1.man (Customization): Document feature.
+
+       * NEWS: Add item.
+
+       Fixes <https://savannah.gnu.org/bugs/?64216>.  Thanks to Doug
+       McIlroy for the report and Damian McGuckin for the discussion.
+
 2023-05-19  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        [eqn]: Add `thick_space` and `thin_space` classes.
diff --git a/NEWS b/NEWS
index 52d47cc27..0fc6ac325 100644
--- a/NEWS
+++ b/NEWS
@@ -19,6 +19,12 @@ o The "gifont" primitive replaces "gfont" as the means of 
configuring
   ease acquisition of the eqn language in light of GNU eqn's
   thirty-year-old extensions "gbfont" and "grfont".
 
+o New parameters tunable with the GNU eqn "set" primitive, "half_space"
+  and "full_space", enable a document to configure the space widths
+  produced by the eqn tokens '^' and '~', respectively.  Previously,
+  their widths were determined by the "thin_space" and "thick_space"
+  parameters used to tune GNU eqn's automatic spacing computations.
+
 Macro packages
 --------------
 
diff --git a/src/preproc/eqn/box.cpp b/src/preproc/eqn/box.cpp
index d63c2800a..18f9226e5 100644
--- a/src/preproc/eqn/box.cpp
+++ b/src/preproc/eqn/box.cpp
@@ -47,8 +47,10 @@ int delimiter_shortfall = 50;
 int null_delimiter_space = 12;
 int script_space = 5;
 int thin_space = 17;
+int half_space = 17;
 int medium_space = 22;
 int thick_space = 28;
+int full_space = 28;
 
 int num1 = 70;
 int num2 = 40;
@@ -94,6 +96,8 @@ struct S {
   { "thin_space", &thin_space },
   { "medium_space", &medium_space },
   { "thick_space", &thick_space },
+  { "half_space", &half_space },
+  { "full_space", &full_space },
   { "num1", &num1 },
   { "num2", &num2 },
   { "denom1", &denom1 },
@@ -597,7 +601,7 @@ half_space_box::half_space_box()
 void half_space_box::output()
 {
   if (output_format == troff)
-    printf("\\h'%dM'", thin_space);
+    printf("\\h'%dM'", half_space);
   else if (output_format == mathml)
     printf("<mtext>&ThinSpace;</mtext>");
 }
@@ -610,10 +614,9 @@ full_space_box::full_space_box()
 void full_space_box::output()
 {
   if (output_format == troff)
-    printf("\\h'%dM'", thick_space);
+    printf("\\h'%dM'", full_space);
   else if (output_format == mathml)
-    // &ThickSpace; doesn't display right under Firefox 1.5.
-    printf("<mtext>&ensp;</mtext>");
+    printf("<mtext>&ThickSpace;</mtext>");
 }
 
 thick_space_box::thick_space_box()
@@ -626,8 +629,7 @@ void thick_space_box::output()
   if (output_format == troff)
     printf("\\h'%dM'", thick_space);
   else if (output_format == mathml)
-    // &ThickSpace; doesn't display right under Firefox 1.5.
-    printf("<mtext>&ensp;</mtext>");
+    printf("<mtext>&ThickSpace;</mtext>");
 }
 
 thin_space_box::thin_space_box()
diff --git a/src/preproc/eqn/eqn.1.man b/src/preproc/eqn/eqn.1.man
index c01690ab8..2821552dd 100644
--- a/src/preproc/eqn/eqn.1.man
+++ b/src/preproc/eqn/eqn.1.man
@@ -1216,11 +1216,6 @@ The width of subscripts and superscripts is increased by 
this amount
 This amount of space is automatically inserted after punctuation
 characters.
 .
-It also configures the width of the space produced by the
-.B \[ha]
-token
-.RB ( 17 ).
-.
 .
 .TP
 .B medium_space
@@ -1234,7 +1229,18 @@ binary operators
 This amount of space is automatically inserted on either side of
 relations.
 .
-It also configures the width of the space produced by the
+.
+.TP
+.B half_space
+configures the width of the space produced by the
+.B \[ha]
+token
+.RB ( 17 ).
+.
+.
+.TP
+.B full_space
+configures the width of the space produced by the
 .B \[ti]
 token
 .RB ( 28 ).
diff --git a/src/preproc/eqn/pbox.h b/src/preproc/eqn/pbox.h
index b18541932..e4cd88e29 100644
--- a/src/preproc/eqn/pbox.h
+++ b/src/preproc/eqn/pbox.h
@@ -1,4 +1,3 @@
-// -*- C++ -*-
 /* Copyright (C) 1989-2020 Free Software Foundation, Inc.
      Written by James Clark (jjc@jclark.com)
 
@@ -30,6 +29,8 @@ extern int script_space;
 extern int thin_space;
 extern int medium_space;
 extern int thick_space;
+extern int half_space;
+extern int full_space;
 
 extern int num1;
 extern int num2;
@@ -138,3 +139,9 @@ void set_script_size();
 enum { HINT_PREV_IS_ITALIC = 01, HINT_NEXT_IS_ITALIC = 02 };
 
 extern const char *current_roman_font;
+
+// Local Variables:
+// fill-column: 72
+// mode: C++
+// End:
+// vim: set cindent noexpandtab shiftwidth=2 textwidth=72: