ANTLR 4 Runtime 4.13.1 · org.antlr.v4.runtime.atn.ATN

Field Summary

Modifier and Type	Field and Description
public final List<DecisionState>	decisionToState Each subrule/rule is a decision point and we must track them so we can go back later and build DFA predictors for them.
public final ATNType	grammarType The type of the ATN.
public static final int	INVALID_ALT_NUMBER
public LexerAction[]	lexerActions For lexer ATNs, this is an array of `LexerAction` objects which may be referenced by action transitions in the ATN.
public final int	maxTokenType The maximum value for any symbol recognized by a transition in the ATN.
public final Map<String, TokensStartState>	modeNameToStartState
public final List<TokensStartState>	modeToStartState
public RuleStartState[]	ruleToStartState Maps from rule index to starting state number.
public RuleStopState[]	ruleToStopState Maps from rule index to stop state number.
public int[]	ruleToTokenType For lexer ATNs, this maps the rule index to the resulting token type.
public final List<ATNState>	states

Constructor Summary

Access	Constructor and Description
public	ATN(ATNType grammarType, int maxTokenType) Used for runtime deserialization of ATNs from strings

Method Summary

Modifier and Type	Method and Description
public void	addState(ATNState state)
public int	defineDecisionState(DecisionState s)
public DecisionState	getDecisionState(int decision)
public IntervalSet	Returns: The set of potentially valid input symbols which could follow the specified state in the specified context. getExpectedTokens(int the ATN state number stateNumber, RuleContext the full parse context context) Computes the set of input symbols which could follow ATN state number `stateNumber` in the specified full `context`.
public int	getNumberOfDecisions()
public IntervalSet	nextTokens(ATNState s, RuleContext ctx) Compute the set of valid tokens that can occur starting in state `s`.
public IntervalSet	nextTokens(ATNState s) Compute the set of valid tokens that can occur starting in `s` and staying in same rule.
public void	removeState(ATNState state)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

decisionToState	back to summary
public final List<DecisionState> decisionToState Each subrule/rule is a decision point and we must track them so we can go back later and build DFA predictors for them. This includes all the rules, subrules, optional blocks, ()+, ()* etc...

grammarType	back to summary
public final ATNType grammarType The type of the ATN.

INVALID_ALT_NUMBER	back to summary
public static final int INVALID_ALT_NUMBER

lexerActions	back to summary
public LexerAction[] lexerActions For lexer ATNs, this is an array of `LexerAction` objects which may be referenced by action transitions in the ATN.

maxTokenType	back to summary
public final int maxTokenType The maximum value for any symbol recognized by a transition in the ATN.

modeNameToStartState	back to summary
public final Map<String, TokensStartState> modeNameToStartState

modeToStartState	back to summary
public final List<TokensStartState> modeToStartState

ruleToStartState	back to summary
public RuleStartState[] ruleToStartState Maps from rule index to starting state number.

ruleToStopState	back to summary
public RuleStopState[] ruleToStopState Maps from rule index to stop state number.

ruleToTokenType	back to summary
public int[] ruleToTokenType For lexer ATNs, this maps the rule index to the resulting token type. For parser ATNs, this maps the rule index to the generated bypass token type if the `ATNDeserializationOptions#isGenerateRuleBypassTransitions` deserialization option was specified; otherwise, this is `null`.

states	back to summary
public final List<ATNState> states

Constructor Detail

ATN	back to summary
public ATN(ATNType grammarType, int maxTokenType) Used for runtime deserialization of ATNs from strings

Method Detail

addState	back to summary
public void addState(ATNState state)

defineDecisionState	back to summary
public int defineDecisionState(DecisionState s)

getDecisionState	back to summary
public DecisionState getDecisionState(int decision)

getExpectedTokens back to summary

getExpectedTokens	back to summary
public IntervalSet getExpectedTokens(int stateNumber, RuleContext context) Computes the set of input symbols which could follow ATN state number `stateNumber` in the specified full `context`. This method considers the complete parser context, but does not evaluate semantic predicates (i.e. all predicates encountered during the calculation are assumed true). If a path in the ATN exists from the starting state to the `RuleStopState` of the outermost context without matching any symbols, `Token#EOF` is added to the returned set. If `context` is `null`, it is treated as `ParserRuleContext#EMPTY`. Note that this does NOT give you the set of all tokens that could appear at a given token position in the input phrase. In other words, it does not answer: "Given a specific partial input phrase, return the set of all tokens that can follow the last token in the input phrase." The big difference is that with just the input, the parser could land right in the middle of a lookahead decision. Getting all possible tokens given a partial input stream is a separate computation. See https://github.com/antlr/antlr4/issues/1428 For this function, we are specifying an ATN state and call stack to compute what token(s) can come next and specifically: outside of a lookahead decision. That is what you want for error reporting and recovery upon parse error. Parameters stateNumber:int the ATN state number context:RuleContext the full parse context Returns:IntervalSet The set of potentially valid input symbols which could follow the specified state in the specified context. Exceptions IllegalArgumentException: if the ATN does not contain a state with number `stateNumber`

public IntervalSet getExpectedTokens(int stateNumber, RuleContext context)

Computes the set of input symbols which could follow ATN state number stateNumber in the specified full context. This method considers the complete parser context, but does not evaluate semantic predicates (i.e. all predicates encountered during the calculation are assumed true). If a path in the ATN exists from the starting state to the RuleStopState of the outermost context without matching any symbols, Token#EOF is added to the returned set.

If context is null, it is treated as ParserRuleContext#EMPTY.

Note that this does NOT give you the set of all tokens that could appear at a given token position in the input phrase. In other words, it does not answer: "Given a specific partial input phrase, return the set of all tokens that can follow the last token in the input phrase." The big difference is that with just the input, the parser could land right in the middle of a lookahead decision. Getting all *possible* tokens given a partial input stream is a separate computation. See https://github.com/antlr/antlr4/issues/1428 For this function, we are specifying an ATN state and call stack to compute what token(s) can come next and specifically: outside of a lookahead decision. That is what you want for error reporting and recovery upon parse error.

Parameters

stateNumber:int: the ATN state number
context:RuleContext: the full parse context

Returns:IntervalSet

The set of potentially valid input symbols which could follow the specified state in the specified context.

Exceptions

IllegalArgumentException:: if the ATN does not contain a state with number stateNumber

getNumberOfDecisions	back to summary
public int getNumberOfDecisions()

nextTokens	back to summary
public IntervalSet nextTokens(ATNState s, RuleContext ctx) Compute the set of valid tokens that can occur starting in state `s`. If `ctx` is null, the set of tokens will not include what can follow the rule surrounding `s`. In other words, the set will be restricted to tokens reachable staying within `s`'s rule.

nextTokens	back to summary
public IntervalSet nextTokens(ATNState s) Compute the set of valid tokens that can occur starting in `s` and staying in same rule. `Token#EPSILON` is in set if we reach end of rule.

removeState	back to summary
public void removeState(ATNState state)