org.antlr.v4.runtime.atn.DecisionEventInfo Maven / Gradle / Ivy
/*
* Copyright (c) 2012-2017 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.antlr.v4.runtime.atn;
import org.antlr.v4.runtime.TokenStream;
/**
* This is the base class for gathering detailed information about prediction
* events which occur during parsing.
*
* Note that we could record the parser call stack at the time this event
* occurred but in the presence of left recursive rules, the stack is kind of
* meaningless. It's better to look at the individual configurations for their
* individual stacks. Of course that is a {@link PredictionContext} object
* not a parse tree node and so it does not have information about the extent
* (start...stop) of the various subtrees. Examining the stack tops of all
* configurations provide the return states for the rule invocations.
* From there you can get the enclosing rule.
*
* @since 4.3
*/
public class DecisionEventInfo {
/**
* The invoked decision number which this event is related to.
*
* @see ATN#decisionToState
*/
public final int decision;
/**
* The configuration set containing additional information relevant to the
* prediction state when the current event occurred, or {@code null} if no
* additional information is relevant or available.
*/
public final ATNConfigSet configs;
/**
* The input token stream which is being parsed.
*/
public final TokenStream input;
/**
* The token index in the input stream at which the current prediction was
* originally invoked.
*/
public final int startIndex;
/**
* The token index in the input stream at which the current event occurred.
*/
public final int stopIndex;
/**
* {@code true} if the current event occurred during LL prediction;
* otherwise, {@code false} if the input occurred during SLL prediction.
*/
public final boolean fullCtx;
public DecisionEventInfo(int decision,
ATNConfigSet configs,
TokenStream input, int startIndex, int stopIndex,
boolean fullCtx)
{
this.decision = decision;
this.fullCtx = fullCtx;
this.stopIndex = stopIndex;
this.input = input;
this.startIndex = startIndex;
this.configs = configs;
}
}