org.antlr.v4.runtime.atn

Class DecisionEventInfo

java.lang.Object

org.antlr.v4.runtime.atn.DecisionEventInfo

Direct Known Subclasses:

AmbiguityInfo, ContextSensitivityInfo, ErrorInfo, LookaheadEventInfo, PredicateEvalInfo

public class DecisionEventInfo
extends Object

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 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

Field Summary

Fields

Modifier and Type	Field and Description
ATNConfigSet	configs The configuration set containing additional information relevant to the prediction state when the current event occurred, or null if no additional information is relevant or available.
int	decision The invoked decision number which this event is related to.
boolean	fullCtx true if the current event occurred during LL prediction; otherwise, false if the input occurred during SLL prediction.
TokenStream	input The input token stream which is being parsed.
int	startIndex The token index in the input stream at which the current prediction was originally invoked.
int	stopIndex The token index in the input stream at which the current event occurred.

Constructor Summary

Constructors

Constructor and Description
DecisionEventInfo(int decision, ATNConfigSet configs, TokenStream input, int startIndex, int stopIndex, boolean fullCtx)

Method Summary

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

decision

public final int decision

The invoked decision number which this event is related to.

See Also:

ATN.decisionToState

configs

public final ATNConfigSet configs

The configuration set containing additional information relevant to the prediction state when the current event occurred, or null if no additional information is relevant or available.

input

public final TokenStream input

The input token stream which is being parsed.

startIndex

public final int startIndex

The token index in the input stream at which the current prediction was originally invoked.

stopIndex

public final int stopIndex

The token index in the input stream at which the current event occurred.

fullCtx

public final boolean fullCtx

true if the current event occurred during LL prediction; otherwise, false if the input occurred during SLL prediction.

Constructor Detail

DecisionEventInfo

public DecisionEventInfo(int decision,
                 ATNConfigSet configs,
                 TokenStream input,
                 int startIndex,
                 int stopIndex,
                 boolean fullCtx)