/*****************************************************************************

 JEP 2.4.1, Extensions 1.1.1
      April 30 2007
      (c) Copyright 2007, Nathan Funk and Richard Morris
      See LICENSE-*.txt for license information.

 *****************************************************************************/
/* Generated By:JJTree: Do not edit this line. JJTParserState.java */

package weasel.jep;


class JJTParserState {
	private java.util.Stack nodes;
	private java.util.Stack marks;

	private int sp;		// number of nodes on stack
	private int mk;		// current mark
	private boolean node_created;

	JJTParserState() {
		nodes = new java.util.Stack();
		marks = new java.util.Stack();
		sp = 0;
		mk = 0;
	}

	/* Determines whether the current node was actually closed and
	   pushed.  This should only be called in the final user action of a
	   node scope.  */
	boolean nodeCreated() {
		return node_created;
	}

	/* Call this to reinitialize the node stack.  It is called
	   automatically by the parser's ReInit() method. */
	void reset() {
		nodes.removeAllElements();
		marks.removeAllElements();
		sp = 0;
		mk = 0;
	}

	/* Returns the root node of the AST.  It only makes sense to call
	   this after a successful parse. */
	Node rootNode() {
		return (Node) nodes.elementAt(0);
	}

	/* Pushes a node on to the stack. */
	void pushNode(Node n) {
		nodes.push(n);
		++sp;
	}

	/* Returns the node on the top of the stack, and remove it from the
	   stack.  */
	Node popNode() {
		if (--sp < mk) {
			mk = ((Integer) marks.pop()).intValue();
		}
		return (Node) nodes.pop();
	}

	/* Returns the node currently on the top of the stack. */
	Node peekNode() {
		return (Node) nodes.peek();
	}

	/* Returns the number of children on the stack in the current node
	   scope. */
	int nodeArity() {
		return sp - mk;
	}


	void clearNodeScope(Node n) {
		while (sp > mk) {
			popNode();
		}
		mk = ((Integer) marks.pop()).intValue();
	}


	void openNodeScope(Node n) {
		marks.push(new Integer(mk));
		mk = sp;
		n.jjtOpen();
	}


	/* A definite node is constructed from a specified number of
	   children.  That number of nodes are popped from the stack and
	   made the children of the definite node.  Then the definite node
	   is pushed on to the stack. */
	void closeNodeScope(Node n, int num) {
		mk = ((Integer) marks.pop()).intValue();
		while (num-- > 0) {
			Node c = popNode();
			c.jjtSetParent(n);
			n.jjtAddChild(c, num);
		}
		n.jjtClose();
		pushNode(n);
		node_created = true;
	}


	/* A conditional node is constructed if its condition is true.  All
	   the nodes that have been pushed since the node was opened are
	   made children of the the conditional node, which is then pushed
	   on to the stack.  If the condition is false the node is not
	   constructed and they are left on the stack. */
	void closeNodeScope(Node n, boolean condition) {
		if (condition) {
			int a = nodeArity();
			mk = ((Integer) marks.pop()).intValue();
			while (a-- > 0) {
				Node c = popNode();
				c.jjtSetParent(n);
				n.jjtAddChild(c, a);
			}
			n.jjtClose();
			pushNode(n);
			node_created = true;
		} else {
			mk = ((Integer) marks.pop()).intValue();
			node_created = false;
		}
	}
}
