1 files changed, 54 insertions, 22 deletions
diff --git a/tex/context/base/mkiv/spac-hor.mkiv b/tex/context/base/mkiv/spac-hor.mkiv
index 405abcb5d..ce747a202 100644
--- a/tex/context/base/mkiv/spac-hor.mkiv
+++ b/tex/context/base/mkiv/spac-hor.mkiv
@@ -15,7 +15,7 @@
 
 \unprotect
 
-\registerctxluafile{spac-hor}{1.001}
+\registerctxluafile{spac-hor}{}
 
 \let    \parfillrightskip \parfillskip
 \newskip\parfillleftskip
@@ -381,9 +381,9 @@
 %D \macros
 %D   {frenchspacing,nonfrenchspacing}
 %D
-%D Somehow \type{\frenchspacing} can lead to hyphenation between
-%D dashes so we now have \type {\newfrenchspacing} (moved from
-%D \type {syst-chr}).
+%D Somehow \type{\frenchspacing} can lead to hyphenation between dashes so we now
+%D have \type {\newfrenchspacing} (moved from \type {syst-chr}). Maybe it's not
+%D needed any more.
 
 %D Hm ... todo:
 
@@ -515,7 +515,7 @@
 \fi
 
 \ifdefined\softhyphen \else
-    \let\softhyphen\-
+    \let\softhyphen\explicitdiscretionary
 \fi
 
 \cldcontext{"\string\\unexpanded\string\\def\string\\\string\n{\string\\space}"}
@@ -680,6 +680,7 @@
                                    \global        \s_spac_narrower_middle \zeropoint
                                    \global        \s_spac_narrower_right  \zeropoint\relax}
 \installnarrowermethod \v!none    {}
+\installnarrowermethod \v!reverse {} % never seen
 
 \unexpanded\def\spac_narrower_start#1%
   {\begingroup
@@ -693,19 +694,45 @@
      \spac_narrower_start_apply{\narrowerparameter\v!default}%
    \fi}
 
+\newskip\s_spac_narrower_left_last
+\newskip\s_spac_narrower_right_last
+\newconditional\s_spac_narrower_last_swap
+
 \def\spac_narrower_start_apply#1%
   {\narrowerparameter\c!before
    \global\s_spac_narrower_left  \zeropoint
    \global\s_spac_narrower_right \zeropoint
    \global\s_spac_narrower_middle\zeropoint
-   \normalexpanded{\processcommalistwithparameters[#1]}\spac_narrower_initialize
-   \advance\leftskip \dimexpr\s_spac_narrower_left +\s_spac_narrower_middle\relax
-   \advance\rightskip\dimexpr\s_spac_narrower_right+\s_spac_narrower_middle\relax
+   \edef\askednarrower{#1}
+   \ifx\askednarrower\v!reverse
+     \ifconditional\s_spac_narrower_last_swap
+       \leftskip \s_spac_narrower_right_last
+       \rightskip\s_spac_narrower_left_last
+       \setfalse\s_spac_narrower_last_swap
+     \else
+       \leftskip \s_spac_narrower_left_last
+       \rightskip\s_spac_narrower_right_last
+       \settrue\s_spac_narrower_last_swap
+     \fi
+   \else
+     \normalexpanded{\processcommalistwithparameters[\askednarrower]}\spac_narrower_initialize
+     \advance\leftskip \dimexpr\s_spac_narrower_left +\s_spac_narrower_middle\relax
+     \advance\rightskip\dimexpr\s_spac_narrower_right+\s_spac_narrower_middle\relax
+   \fi
    \seteffectivehsize}
 
 \unexpanded\def\spac_narrower_stop
   {\narrowerparameter\c!after
-   \endgroup}
+   \normalexpanded{%
+      \endgroup
+      \s_spac_narrower_left_last \the\leftskip \relax
+      \s_spac_narrower_right_last\the\rightskip\relax
+      \ifconditional\s_spac_narrower_last_swap
+        \setfalse\s_spac_narrower_last_swap
+      \else
+        \settrue\s_spac_narrower_last_swap
+      \fi
+   }}
 
 \unexpanded\def\startnarrower
   {\dosingleempty\spac_narrower_start_basic}
@@ -822,14 +849,16 @@
     \forgetbothskips
 \to \everyforgetall
 
-\unexpanded\def\forgetparskip
-  {\s_spac_whitespace_parskip\zeropoint
-   \parskip\zeropoint
-   \let\v_spac_whitespace_current\v!none}
-
-\appendtoks
-    \forgetparskip
-\to \everyforgetall
+% in spac-ver.mkiv
+%
+% \unexpanded\def\forgetparskip
+%   {\s_spac_whitespace_parskip\zeropoint
+%    \parskip\zeropoint
+%    \let\v_spac_whitespace_current\v!none}
+%
+% \appendtoks
+%     \forgetparskip
+% \to \everyforgetall
 
 %D Tolerance (can also be set with align):
 
@@ -1013,19 +1042,22 @@
 %D adapted to \type {\hspace}:
 
 \unexpanded\def\textormathspace         #1#2#3{\ifmmode\mskip#1#2\else\kern #1\hspaceamount\empty{#3}\fi\relax}
+\unexpanded\def\textormathspacecommand  #1#2#3{\ifmmode\mskip#1#2\else#3\fi\relax}
 \unexpanded\def\breakabletextormathspace#1#2#3{\ifmmode\mskip#1#2\else\hskip#1\hspaceamount\empty{#3}\fi\relax}
 
 \newmuskip\hairmuskip \hairmuskip=.15mu
 
 \unexpanded\def\hairspace    {\textormathspace+\hairmuskip{.5}}
 \unexpanded\def\thinspace    {\textormathspace+\thinmuskip 1}
-\unexpanded\def\medspace     {\textormathspace+\medmuskip  2}
+%unexpanded\def\medspace     {\textormathspace+\medmuskip  2}      % 4/18 em
 \unexpanded\def\thickspace   {\textormathspace+\thickmuskip3}
 \unexpanded\def\neghairspace {\textormathspace-\thinmuskip{.5}}
 \unexpanded\def\negthinspace {\textormathspace-\thinmuskip 1}
 \unexpanded\def\negmedspace  {\textormathspace-\medmuskip  2}
 \unexpanded\def\negthickspace{\textormathspace-\thickmuskip3}
 
+\unexpanded\edef\medspace    {\textormathspacecommand+\medmuskip{\Uchar"205F}}
+
 % needed for unicode:
 
 %unexpanded\def\breakablethinspace      {\breakabletextormathspace+\thinmuskip1}
@@ -1043,10 +1075,10 @@
 %unexpanded\def\zerowidthnobreakspace   {\penalty\plustenthousand\kern\zeropoint}
 %unexpanded\def\zerowidthspace          {\hskip\zeropoint}
 
-\definehspace[.5][.1250\emspaceamount] % could also be [.1250\spaceamount]
-\definehspace[1] [.1667\emspaceamount]
-\definehspace[2] [.2222\emspaceamount]
-\definehspace[3] [.2777\emspaceamount]
+\definehspace[.5][.1250\emwidth] % hair
+\definehspace[1] [.1667\emwidth] % thin
+\definehspace[2] [.2222\emwidth] % med
+\definehspace[3] [.2777\emwidth] % thick
 
 \let \, \thinspace
 \let \: \medspace