walk method
Implementation
void walk(ParseTreeListener listener, ParseTree t) {
if (t is ErrorNode) {
listener.visitErrorNode(t);
return;
} else if (t is TerminalNode) {
listener.visitTerminal(t);
return;
}
final r = t as RuleNode;
enterRule(listener, r);
for (var i = 0; i < r.childCount; i++) {
walk(listener, r.getChild(i)!);
}
exitRule(listener, r);
}