3 files changed, 27 insertions, 10 deletions
diff --git a/Build/source/texk/web2c/cwebdir/ChangeLog b/Build/source/texk/web2c/cwebdir/ChangeLog
index 1a36c3bbc47..e11fb23cf9b 100644
--- a/Build/source/texk/web2c/cwebdir/ChangeLog
+++ b/Build/source/texk/web2c/cwebdir/ChangeLog
@@ -1,3 +1,8 @@
+2020-05-22  Andreas Scherer  <https://ascherer.github.io>
+
+	* texinputs/Xcwebmac.tex: Activate alternative assignment operator.
+	* texinputs/pdfwebtocfront.tex: Add comments to the macro code.
+
 2020-05-07  Andreas Scherer  <https://ascherer.github.io>
 
 	* texinputs/Xcwebmac.tex: Amend macros from knuth.drv (n
diff --git a/Build/source/texk/web2c/cwebdir/texinputs/Xcwebmac.tex b/Build/source/texk/web2c/cwebdir/texinputs/Xcwebmac.tex
index e608d5f8b0e..c2a8b4115ad 100644
--- a/Build/source/texk/web2c/cwebdir/texinputs/Xcwebmac.tex
+++ b/Build/source/texk/web2c/cwebdir/texinputs/Xcwebmac.tex
@@ -25,10 +25,11 @@
 % Version 3.64 [p20] --- Andreas Scherer, March 2002
 % Version 3.64 [p21] --- Andreas Scherer, Octobre 2005
 % Version 3.64 [2018] --- Andreas Scherer, Octobre 2018
+% Version 3.64 [2020] --- Andreas Scherer, May 2020
 
 \ifx\undefined\botofcontents\input cwebmac.tex\fi
 
-\xdef\fmtversion{\fmtversion[2018]}
+\xdef\fmtversion{\fmtversion[2020]}
 
 \def\Cpp{\CPLUSPLUS/} % for backward compatibility
 
@@ -37,4 +38,4 @@
 \def\C#1{\5\5\quad$\triangleright\,${\cmntfont#1}$\,\triangleleft$}
 \def\SHC#1{\5\5\quad$\diamond\,${\cmntfont#1}}
 
-%\let\K=\leftarrow % "honest" alternative to standard assignment operator
+\let\K=\leftarrow % "honest" alternative to standard assignment operator
diff --git a/Build/source/texk/web2c/cwebdir/texinputs/pdfwebtocfront.tex b/Build/source/texk/web2c/cwebdir/texinputs/pdfwebtocfront.tex
index 3fb8d393a4e..be662846096 100644
--- a/Build/source/texk/web2c/cwebdir/texinputs/pdfwebtocfront.tex
+++ b/Build/source/texk/web2c/cwebdir/texinputs/pdfwebtocfront.tex
@@ -1,32 +1,44 @@
+% pdfwebtofront.tex
+% Code from knuth.drv in https://github.com/oberdiek/latex-tds
+% 2020/05/21 v1.0 by Andreas Scherer.
 %
-% Move contents page to the front
+% This file is part of project https://github.com/ascherer/cwebbin
+% and may be distributed under the MIT License or the LaTeX Project
+% Public License.
 %
-% Code from knuth.drv in https://github.com/oberdiek/latex-tds
-% Works with pdftex and xetex.
+% Move table-of-contents page to the front in PDF output.
+% Works with pdftex and xetex in connection with either 'webmac.tex'
+% for Pascal/WEB programs or 'cwebmac.tex' for C/CWEB programs.
 %
 \ifx\detokenize\undefined\endinput\fi
 \newread\testread
 \openin\testread=\contentsfile\relax
 \ifeof\testread % First run
 \else % Second run
-  \let\ORGcon\con
+  \let\ORGcon\con \let\ORGtoc\topofcontents
+  \ifx\undefined\grouptitle \mark{1} % WEB: let's start with section '1'.
+  \else\def\topofcontents{\ORGtoc\gtitle={\the\grouptitle}}\fi % CWEB
+  % Redefine '\con' to be invoked before the first '\N' (starred section).
   \def\con{%
-    \ifnum\pageno=1 \global\titletrue\fi
+    \def\:{\par\hangindent 2em} % Fix for 'bibtex.web'.
     \begingroup
       \let\end\relax
-      \ORGcon
+      \ORGcon\eject
     \endgroup
     \let\con\end
   }%
+  % Redefine '\N’ to invoke redefined '\con' before switching back
+  % to original '\N'.
   \expandafter\let\csname ORGN\expandafter\endcsname
                   \csname N\endcsname
   \expandafter\outer\expandafter\def\csname N\endcsname{%
     \con
-    \advance\pageno by -1\relax
     \expandafter\let\csname N\expandafter\endcsname
                     \csname ORGN\endcsname
     \csname N\endcsname
   }%
+  % Special variant of the above for 'mf.web' and 'tex.web'.  They put
+  % their tables-of-contents on a sparce 'page 2' and start on page '3'.
   \begingroup
     \def\num{0}%
     \edef\x{\jobname}%
@@ -48,7 +60,6 @@
                       \csname N\endcsname
       \expandafter\outer\expandafter\def\csname N\endcsname{%
         \con
-        \advance\pageno by -1\relax
         \expandafter\let\csname N\expandafter\endcsname
                         \csname ORGN\endcsname
         \csname N\endcsname