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/*
 * Copyright (c) 2012 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD-3-Clause license that
 * can be found in the LICENSE.txt file in the project root.
 */
package org.pkl.thirdparty.antlr.v4.runtime;

import org.pkl.thirdparty.antlr.v4.runtime.misc.Interval;
import org.pkl.thirdparty.antlr.v4.runtime.misc.Nullable;
import org.pkl.thirdparty.antlr.v4.runtime.tree.ErrorNode;
import org.pkl.thirdparty.antlr.v4.runtime.tree.ErrorNodeImpl;
import org.pkl.thirdparty.antlr.v4.runtime.tree.ParseTree;
import org.pkl.thirdparty.antlr.v4.runtime.tree.ParseTreeListener;
import org.pkl.thirdparty.antlr.v4.runtime.tree.TerminalNode;
import org.pkl.thirdparty.antlr.v4.runtime.tree.TerminalNodeImpl;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/** A rule invocation record for parsing.
 *
 *  Contains all of the information about the current rule not stored in the
 *  RuleContext. It handles parse tree children list, Any ATN state
 *  tracing, and the default values available for rule invocations:
 *  start, stop, rule index, current alt number.
 *
 *  Subclasses made for each rule and grammar track the parameters,
 *  return values, locals, and labels specific to that rule. These
 *  are the objects that are returned from rules.
 *
 *  Note text is not an actual field of a rule return value; it is computed
 *  from start and stop using the input stream's toString() method.  I
 *  could add a ctor to this so that we can pass in and store the input
 *  stream, but I'm not sure we want to do that.  It would seem to be undefined
 *  to get the .text property anyway if the rule matches tokens from multiple
 *  input streams.
 *
 *  I do not use getters for fields of objects that are used simply to
 *  group values such as this aggregate.  The getters/setters are there to
 *  satisfy the superclass interface.
 */
public class ParserRuleContext extends RuleContext {
	private static final ParserRuleContext EMPTY = new ParserRuleContext();

	/** If we are debugging or building a parse tree for a visitor,
	 *  we need to track all of the tokens and rule invocations associated
	 *  with this rule's context. This is empty for parsing w/o tree constr.
	 *  operation because we don't the need to track the details about
	 *  how we parse this rule.
	 */
	public List children;

	/** For debugging/tracing purposes, we want to track all of the nodes in
	 *  the ATN traversed by the parser for a particular rule.
	 *  This list indicates the sequence of ATN nodes used to match
	 *  the elements of the children list. This list does not include
	 *  ATN nodes and other rules used to match rule invocations. It
	 *  traces the rule invocation node itself but nothing inside that
	 *  other rule's ATN submachine.
	 *
	 *  There is NOT a one-to-one correspondence between the children and
	 *  states list. There are typically many nodes in the ATN traversed
	 *  for each element in the children list. For example, for a rule
	 *  invocation there is the invoking state and the following state.
	 *
	 *  The parser setState() method updates field s and adds it to this list
	 *  if we are debugging/tracing.
	 *
	 *  This does not trace states visited during prediction.
	 */
//	public List states;

	public Token start, stop;

	/**
	 * The exception that forced this rule to return. If the rule successfully
	 * completed, this is {@code null}.
	 */
	public RecognitionException exception;

	public ParserRuleContext() { }

	public static ParserRuleContext emptyContext() {
		return EMPTY;
	}

	/**
	 * COPY a ctx (I'm deliberately not using copy constructor) to avoid
	 * confusion with creating node with parent. Does not copy children
	 * (except error leaves).
	 *
	 * 

This is used in the generated parser code to flip a generic XContext * node for rule X to a YContext for alt label Y. In that sense, it is not * really a generic copy function.

* *

If we do an error sync() at start of a rule, we might add error nodes * to the generic XContext so this function must copy those nodes to the * YContext as well else they are lost!

*/ public void copyFrom(ParserRuleContext ctx) { this.parent = ctx.parent; this.invokingState = ctx.invokingState; this.start = ctx.start; this.stop = ctx.stop; // copy any error nodes to alt label node if ( ctx.children!=null ) { this.children = new ArrayList(); // reset parent pointer for any error nodes for (ParseTree child : ctx.children) { if (child instanceof ErrorNodeImpl) { ((ErrorNodeImpl)child).setParent(this); } addAnyChild(child); } } } public ParserRuleContext(@Nullable ParserRuleContext parent, int invokingStateNumber) { super(parent, invokingStateNumber); } // Double dispatch methods for listeners public void enterRule(ParseTreeListener listener) { } public void exitRule(ParseTreeListener listener) { } /** Add a parse tree node to this as a child. Works for * internal and leaf nodes. Does not set parent link; * other add methods must do that. Other addChild methods * call this. * * We cannot set the parent pointer of the incoming node * because the existing interfaces do not have a setParent() * method and I don't want to break backward compatibility for this. * * @since 4.7 */ public T addAnyChild(T t) { assert t.getParent() == null || t.getParent() == this; if ( children==null ) children = new ArrayList(); children.add(t); return t; } public void addChild(RuleContext ruleInvocation) { addAnyChild(ruleInvocation); } /** Add a token leaf node child. */ public void addChild(TerminalNode t) { addAnyChild(t); } /** Add an error node child. * * @since 4.7 */ public ErrorNode addErrorNode(ErrorNode errorNode) { return addAnyChild(errorNode); } /** Add a child to this node based upon matchedToken. It * creates a TerminalNodeImpl rather than using * {@link Parser#createTerminalNode(ParserRuleContext, Token)}. I'm leaving this * in for compatibility but the parser doesn't use this anymore. */ @Deprecated public TerminalNode addChild(Token matchedToken) { TerminalNodeImpl t = new TerminalNodeImpl(matchedToken); addAnyChild(t); t.setParent(this); return t; } /** Add a child to this node based upon badToken. It * creates a ErrorNodeImpl rather than using * {@link Parser#createErrorNode(ParserRuleContext, Token)}. I'm leaving this * in for compatibility but the parser doesn't use this anymore. */ @Deprecated public ErrorNode addErrorNode(Token badToken) { ErrorNodeImpl t = new ErrorNodeImpl(badToken); addAnyChild(t); t.setParent(this); return t; } // public void trace(int s) { // if ( states==null ) states = new ArrayList(); // states.add(s); // } /** Used by enterOuterAlt to toss out a RuleContext previously added as * we entered a rule. If we have # label, we will need to remove * generic ruleContext object. */ public void removeLastChild() { if ( children!=null ) { children.remove(children.size()-1); } } @Override /** Override to make type more specific */ public ParserRuleContext getParent() { return (ParserRuleContext)super.getParent(); } @Override public ParseTree getChild(int i) { return children!=null && i>=0 && i T getChild(Class ctxType, int i) { if ( children==null || i < 0 || i >= children.size() ) { return null; } int j = -1; // what element have we found with ctxType? for (ParseTree o : children) { if ( ctxType.isInstance(o) ) { j++; if ( j == i ) { return ctxType.cast(o); } } } return null; } public TerminalNode getToken(int ttype, int i) { if ( children==null || i < 0 || i >= children.size() ) { return null; } int j = -1; // what token with ttype have we found? for (ParseTree o : children) { if ( o instanceof TerminalNode ) { TerminalNode tnode = (TerminalNode)o; Token symbol = tnode.getSymbol(); if ( symbol.getType()==ttype ) { j++; if ( j == i ) { return tnode; } } } } return null; } public List getTokens(int ttype) { if ( children==null ) { return Collections.emptyList(); } List tokens = null; for (ParseTree o : children) { if ( o instanceof TerminalNode ) { TerminalNode tnode = (TerminalNode)o; Token symbol = tnode.getSymbol(); if ( symbol.getType()==ttype ) { if ( tokens==null ) { tokens = new ArrayList(); } tokens.add(tnode); } } } if ( tokens==null ) { return Collections.emptyList(); } return tokens; } public T getRuleContext(Class ctxType, int i) { return getChild(ctxType, i); } public List getRuleContexts(Class ctxType) { if ( children==null ) { return Collections.emptyList(); } List contexts = null; for (ParseTree o : children) { if ( ctxType.isInstance(o) ) { if ( contexts==null ) { contexts = new ArrayList(); } contexts.add(ctxType.cast(o)); } } if ( contexts==null ) { return Collections.emptyList(); } return contexts; } @Override public int getChildCount() { return children!=null ? children.size() : 0; } @Override public Interval getSourceInterval() { if ( start == null ) { return Interval.INVALID; } if ( stop==null || stop.getTokenIndex() rules = recognizer.getRuleInvocationStack(this); Collections.reverse(rules); return "ParserRuleContext"+rules+"{" + "start=" + start + ", stop=" + stop + '}'; } }




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