\cdbalgorithm{amnesia}{}

Forget the history of the indicated expression, that is, remove all
previous forms of the expression from memory. 
\begin{screen}{1,2,4,5}
A (B + C);
@distribute!(%);
A B + A C;
@amnesia(%);
@pop(%);
@pop: not applicable.
\end{screen}
This is mainly useful to purge extremely long intermediate expressions
from memory, while still retaining the option to use the expression
history for other expressions (instead of switching expression
histories off altogether with \subsprop{KeepHistory}).

\cdbseealgo{pop}
\cdbseeprop{KeepHistory}
