%%% Null control sequence

% When you do:

    \endlinechar=-1
    \let\x\

% the macro \x is undefined\dots

% Actually \x becomes equal to the 'null control sequence' that
% you would get from 

	\expandafter\def\csname\endcsname{}

% but that is usually undefined.

% And you can even use this effect to assign to the null control
% sequence without needing \expandafter:

	\endlinechar=-1
	\gdef\
		{\message{NULL CS}}

	\csname\endcsname

\end
