cases (11mar20)

git-svn-id: svn://tug.org/texlive/trunk@54238 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 15 insertions, 10 deletions

diff --git a/Master/texmf-dist/tex/latex/cases/cases.sty b/Master/texmf-dist/tex/latex/cases/cases.sty
index 66609ee492c..13d2effa549 100644
--- a/Master/texmf-dist/tex/latex/cases/cases.sty
+++ b/Master/texmf-dist/tex/latex/cases/cases.sty
@@ -1,4 +1,4 @@
-%  C A S E S . S T Y             ver 3.0    Feb 2020
+%  C A S E S . S T Y             ver 3.1    Mar 2020
 %
 %  Copyright (C) 1993,1994,1995,2000,2002,2020 by Donald Arseneau
 %                                       asnd@triumf.ca
@@ -30,11 +30,11 @@
 %
 %  For detailed description and package options, see cases.pdf (cases.tex).
  
-\ProvidesPackage{cases}[2020/02/22 ver 3.0]
+\ProvidesPackage{cases}[2020/03/10 ver 3.1]
 
 \newdimen\numc@numwid
 
-% copy \@@eqncr but change error message and handle \tag{} for amsmath:
+% copy \@@eqncr but change error message and handle \tag for amsmath:
 \def\@@numc@cr{\let\reserved@a\relax
     \ifcase\@eqcnt \def\reserved@a{& & &}\or \def\reserved@a{& &}%
      \or \def\reserved@a{&}\else
@@ -42,7 +42,6 @@
        \@latex@error{Too many columns in numcases environment}\@ehc\fi
      \reserved@a \if@eqnsw\@eqnnum\stepcounter{equation}\else \iftag@ \df@tag\fi\fi
      \global\@eqnswtrue\global\@eqcnt\z@\cr}
-
 \let\iftag@=\iffalse
 
 \newenvironment{numcases}[1]%
@@ -54,7 +53,7 @@
  \numc@setsub % maybe \subequations (handling \refstepcounter)
  \def\@currentlabel{\p@equation\theequation}%
  \global\@eqnswtrue\m@th
- \def\tag##1{\def\@currentlabel{##1}\tag@in@align{##1}}%
+ \let\tag\numc@tag
  \settowidth{\numc@numwid}{\ \advance\c@equation\tw@\numc@eqnnum}%
  \@tempskipb\@centering
  \ifx\numc@left\mathindent % fleqn:
@@ -74,9 +73,9 @@
   \everycr{}\let\\\@eqncr \let\@@eqncr\@@numc@cr
   \tabskip\@tempskipa
   \halign to\dimen@ii \bgroup % white space for LHS followed by RHS
-    \kern\wd\z@ \kern10\p@ % assume width of brace
-    \global\let\iftag@=\iffalse % for amsmath (make sure this is not in if block)
-    \global\@eqcnt\@ne $\numc@dispstyle{##}$\hfil 
+    \kern\wd\z@ \kern10\p@ % assume (and force) width of brace
+    \global\let\iftag@=\iffalse % for amsmath (make sure this is not in \if block)
+    \global\@eqcnt\@ne $\numc@dispstyle ##\relax$\hfil 
     \tabskip\z@skip &% explanation
     \global\@eqcnt\tw@
     \numc@expstyle\quad ##\unskip\numc@expstyle\hfil % \unskip removes quad if no explanation
@@ -133,6 +132,11 @@ $$\global\@ignoretrue}
 
 \@ifundefined{c@parentequation}{% No AMS
 \def\numc@eqnnum{\@eqnnum}
+% for \tag (but not \tag*) without amsmath, using \@@numc@cr above.
+\def\numc@tag#1{\def\@currentlabel{#1}%
+  \gdef\df@tag{\def\theequation{#1}\@eqnnum}%
+  \global\let\iftag@=\iftrue
+  \nonumber}
 %
 % These versions of subequations follow the style of Gildea's subeqn.sty,
 % but are thoroughly rewritten.  
@@ -184,8 +188,9 @@ $$\global\@ignoretrue}
 %  \subequations already defined;
 % use tag format
 \def\numc@eqnnum{\tagform@{\theequation}}    
-% add little space after brace to amsmath's cases
+\def\numc@tag{\tag@in@align}
 
+% add little space after brace to amsmath's cases
 \def\@tempa{%
   \let\@ifnextchar\new@ifnextchar
   \left\lbrace
@@ -241,7 +246,7 @@ $$\global\@ignoretrue}
     \openup\jot
     \tabskip\z@skip 
     \halign \bgroup 
-      $\numc@dispstyle{##}\m@th$\hfil 
+      $\numc@dispstyle ##\m@th$\hfil 
       &\numc@expstyle\quad ##\unskip\numc@expstyle\hfil % \unskip removes space if no explanations
       \cr
  }{%