\documentclass{article}
\def\assigned{[Assigned!]}
\def\alsoassigned{[Also Assigned!]}
\def\grouped{[Grouped!]}
\def\alsogrouped{[Also Grouped!]}
\def\one{[One]}
\def\two{[Two]}
\def\three{[Three]}

\newbox\ABox
\newcount\mycounter\mycounter=0
\begin{document}
\section{AfterAssignment}

def:\afterassignment\assigned
\def\foo{[foo]}

let:\afterassignment\assigned
\let\bax\foo

futurelet:\afterassignment\assigned
\futurelet\bax\one\two\three\bax

chardef:\afterassignment\assigned
\chardef\beep=10

mathchardef:\afterassignment\assigned
\mathchardef\bah=1000

\makeatletter
@ifundefined:
\afterassignment\assigned
\@ifundefined{quirks}{No quirks}{Have quirks}
\makeatother

csname:\afterassignment\assigned
\csname nothingatall \endcsname

{{{\afterassignment\assigned}}}
counter:\mycounter=1\relax\the\mycounter
counter:\mycounter=2\relax\the\mycounter


{
\afterassignment\assigned
counter:\mycounter=3\relax\the\mycounter
counter:\mycounter=4\relax\the\mycounter
}


{
\afterassignment\assigned
\afterassignment\alsoassigned
counter:\mycounter=5\relax\the\mycounter
counter:\mycounter=6\relax\the\mycounter
}


\afterassignment\assigned
\setbox\ABox=\hbox{inside}
setbox Before \copy\ABox After

\setbox\ABox=\hbox{inside}
Again setbox Before \copy\ABox After


\afterassignment\alsoassigned
Before \hbox{inside} After\mycounter=99

\section{AfterGroup}
before { middle } after

before { \aftergroup\grouped middle } after

not {\em emphasized} not

\subsection{AfterGroup in Environments}
\begin{quote}
before \em  after
\end{quote}

\begin{quote}
before \aftergroup\grouped after
\end{quote}

\section{vadjust}
Paragraph\vadjust{X}, More.

Another paragraph.

\section{Every Box}

\def\HBox{ HBOX }
\def\VBox{ VBOX }

\vbox{\hbox{An Hbox}\hbox{Another Hbox}}

\everyhbox={\HBox}
\everyvbox={\VBox}
\vbox{\hbox{An Hbox}\hbox{Another Hbox}}

\everyhbox={}
\everyvbox={}


% \everymath is NOT (yet) supported.
% \section{EveryMath}
% \everymath={.}
% $a+b$

% \everymath={}
%  $a+b$

% $ a + \everymath={} b$

\end{document}
