Examples with IntegerStack org.antlr.v4.runtime.misc.IntegerStack used on opensource projects

Example 1 with IntegerStack

use of org.antlr.v4.runtime.misc.IntegerStack in project antlr4 by antlr.

the class IterativeParseTreeWalker method walk.

@Override
public void walk(ParseTreeListener listener, ParseTree t) {
    final Deque<ParseTree> nodeStack = new ArrayDeque<ParseTree>();
    final IntegerStack indexStack = new IntegerStack();
    ParseTree currentNode = t;
    int currentIndex = 0;
    while (currentNode != null) {
        // pre-order visit
        if (currentNode instanceof ErrorNode) {
            listener.visitErrorNode((ErrorNode) currentNode);
        } else if (currentNode instanceof TerminalNode) {
            listener.visitTerminal((TerminalNode) currentNode);
        } else {
            final RuleNode r = (RuleNode) currentNode;
            enterRule(listener, r);
        }
        // Move down to first child, if exists
        if (currentNode.getChildCount() > 0) {
            nodeStack.push(currentNode);
            indexStack.push(currentIndex);
            currentIndex = 0;
            currentNode = currentNode.getChild(0);
            continue;
        }
        // No child nodes, so walk tree
        do {
            // post-order visit
            if (currentNode instanceof RuleNode) {
                exitRule(listener, (RuleNode) currentNode);
            }
            // No parent, so no siblings
            if (nodeStack.isEmpty()) {
                currentNode = null;
                currentIndex = 0;
                break;
            }
            // Move to next sibling if possible
            currentNode = nodeStack.peek().getChild(++currentIndex);
            if (currentNode != null) {
                break;
            }
            // No next, sibling, so move up
            currentNode = nodeStack.pop();
            currentIndex = indexStack.pop();
        } while (currentNode != null);
    }
}