Tree utilities


\begin{inset}{} Returns a result tree which is the same as the argument {\it tre... ...y {\tt SUBST} may or may not share structure with its tree argument. \end{inset}


\begin{inset}{} \begin{codexenv} (SUBSTQ {\it new old tree\/}) $\equiv$\ (SUBST EQ? {\it new old tree\/}) \end{codexenv}\end{inset}


\begin{inset}{} \begin{codexenv} (SUBSTV {\it new old tree\/}) $\equiv$\ (SUBST EQUIV? {\it new old tree\/}) \end{codexenv}\end{inset}


\begin{inset}{} Recursively make a copy of the {\it tree\/}. \begin{codexenv} (C... ... {\it tree\/}) $\equiv$\ (SUBSTQ NIL NIL {\it tree\/}) \end{codexenv}\end{inset}


\begin{inset}{} Compute a \ix{hash code} for {\it tree\/}. The hash computed is ... ...and {\it tree2\/} are {\tt ALIKEV?}, then their hashes are the same. \end{inset}