Performs a walk on the given parse tree starting at the root and going down recursively
with depth-first search. On each node, {@link ParseTreeWalker#enterRule} is called before
recursively walking down into child nodes, then
{@link ParseTreeWalker#exitRule} is called after the recursive call to wind up.
@param listener The listener used by the walker to process grammar rules
@param t The parse tree to be walked on
Performs a walk on the given parse tree starting at the root and going down recursively with depth-first search. On each node, {@link ParseTreeWalker#enterRule} is called before recursively walking down into child nodes, then {@link ParseTreeWalker#exitRule} is called after the recursive call to wind up. @param listener The listener used by the walker to process grammar rules @param t The parse tree to be walked on