Modifier and Type	Class and Description
protected static class	LexerATNSimulator.SimState When we hit an accept state in either the DFA or the ATN, we have to notify the character stream to start buffering characters via `IntStream#mark` and record the current state.

Modifier and Type	Field and Description
protected int	charPositionInLine The index of the character relative to the beginning of the line 0..n-1
public static final boolean	debug
public final DFA[]	decisionToDFA
public static final boolean	dfa_debug
protected int	line line number 1..n within the input
public static final int	MAX_DFA_EDGE
public static final int	MIN_DFA_EDGE
protected int	mode
protected final LexerATNSimulator.SimState	prevAccept Used during DFA/ATN exec to record the most recent accept configuration info
protected final Lexer	recog
protected int	startIndex The current token's starting index into the character stream.

Access	Constructor and Description
public	LexerATNSimulator(ATN atn, DFA[] decisionToDFA, PredictionContextCache sharedContextCache)
public	LexerATNSimulator(Lexer recog, ATN atn, DFA[] decisionToDFA, PredictionContextCache sharedContextCache)

Method Summary

Modifier and Type	Method and Description
protected void	accept(CharStream input, LexerActionExecutor lexerActionExecutor, int startIndex, int index, int line, int charPos)
protected DFAState	addDFAEdge(DFAState from, int t, ATNConfigSet q)
protected void	addDFAEdge(DFAState p, int t, DFAState q)
protected DFAState	addDFAState(ATNConfigSet configs) Add a new DFA state if there isn't one with this set of configurations already.
protected void	captureSimState(LexerATNSimulator.SimState settings, CharStream input, DFAState dfaState)
public void	clearDFA() Overrides org.antlr.v4.runtime.atn.ATNSimulator.clearDFA. Clear the DFA cache used by the current instance.
protected boolean	Returns: `true` if an accept state is reached, otherwise `false`. closure(CharStream input, LexerATNConfig config, ATNConfigSet configs, boolean currentAltReachedAcceptState, boolean speculative, boolean treatEofAsEpsilon) Since the alternatives within any lexer decision are ordered by preference, this method stops pursuing the closure as soon as an accept state is reached.
protected ATNConfigSet	computeStartState(CharStream input, ATNState p)
protected DFAState	Returns: The computed target DFA state for the given input symbol `t`. If `t` does not lead to a valid DFA state, this method returns `ERROR`. computeTargetState(CharStream The input stream input, DFAState The current DFA state s, int The next input symbol t) Compute a target state for an edge in the DFA, and attempt to add the computed state and corresponding edge to the DFA.
public void	consume(CharStream input)
public void	copyState(LexerATNSimulator simulator)
protected boolean	Returns: `true` if the specified predicate evaluates to `true`. evaluatePredicate(CharStream The input stream. input, int The rule containing the predicate. ruleIndex, int The index of the predicate within the rule. predIndex, boolean `true` if the current index in `input` is one character before the predicate's location. speculative) Evaluate a predicate specified in the lexer.
protected int	execATN(CharStream input, DFAState ds0)
protected int	failOrAccept(LexerATNSimulator.SimState prevAccept, CharStream input, ATNConfigSet reach, int t)
public int	getCharPositionInLine()
public final DFA	getDFA(int mode)
protected LexerATNConfig	getEpsilonTarget(CharStream input, LexerATNConfig config, Transition t, ATNConfigSet configs, boolean speculative, boolean treatEofAsEpsilon)
protected DFAState	Returns: The existing target DFA state for the given input symbol `t`, or `null` if the target state for this edge is not already cached getExistingTargetState(DFAState The current DFA state s, int The next input symbol t) Get an existing target state for an edge in the DFA.
public int	getLine()
protected void	getReachableConfigSet(CharStream input, ATNConfigSet closure, ATNConfigSet reach, int t) Given a starting configuration set, figure out all ATN configurations we can reach upon input `t`.
protected ATNState	getReachableTarget(Transition trans, int t)
public String	getText(CharStream input) Get the text matched so far for the current token.
public String	getTokenName(int t)
public int	match(CharStream input, int mode)
protected int	matchATN(CharStream input)
public void	reset() Implements abstract org.antlr.v4.runtime.atn.ATNSimulator.reset.
public void	setCharPositionInLine(int charPositionInLine)
public void	setLine(int line)

Inherited from org.antlr.v4.runtime.atn.ATNSimulator:: getCachedContext getSharedContextCache

Field Detail

charPositionInLine	back to summary
protected int charPositionInLine The index of the character relative to the beginning of the line 0..n-1

debug	back to summary
public static final boolean debug

decisionToDFA	back to summary
public final DFA[] decisionToDFA

dfa_debug	back to summary
public static final boolean dfa_debug

line	back to summary
protected int line line number 1..n within the input

MAX_DFA_EDGE	back to summary
public static final int MAX_DFA_EDGE

MIN_DFA_EDGE	back to summary
public static final int MIN_DFA_EDGE

mode	back to summary
protected int mode

prevAccept	back to summary
protected final LexerATNSimulator.SimState prevAccept Used during DFA/ATN exec to record the most recent accept configuration info

recog	back to summary
protected final Lexer recog

startIndex	back to summary
protected int startIndex The current token's starting index into the character stream. Shared across DFA to ATN simulation in case the ATN fails and the DFA did not have a previous accept state. In this case, we use the ATN-generated exception object.

Constructor Detail

LexerATNSimulator	back to summary
public LexerATNSimulator(ATN atn, DFA[] decisionToDFA, PredictionContextCache sharedContextCache)

LexerATNSimulator	back to summary
public LexerATNSimulator(Lexer recog, ATN atn, DFA[] decisionToDFA, PredictionContextCache sharedContextCache)

Method Detail

accept	back to summary
protected void accept(CharStream input, LexerActionExecutor lexerActionExecutor, int startIndex, int index, int line, int charPos)

addDFAEdge	back to summary
protected DFAState addDFAEdge(DFAState from, int t, ATNConfigSet q)

addDFAEdge	back to summary
protected void addDFAEdge(DFAState p, int t, DFAState q)

addDFAState	back to summary
protected DFAState addDFAState(ATNConfigSet configs) Add a new DFA state if there isn't one with this set of configurations already. This method also detects the first configuration containing an ATN rule stop state. Later, when traversing the DFA, we will know which rule to accept.

captureSimState	back to summary
protected void captureSimState(LexerATNSimulator.SimState settings, CharStream input, DFAState dfaState)

clearDFA	back to summary
public void clearDFA() Overrides org.antlr.v4.runtime.atn.ATNSimulator.clearDFA. Doc from org.antlr.v4.runtime.atn.ATNSimulator.clearDFA. Clear the DFA cache used by the current instance. Since the DFA cache may be shared by multiple ATN simulators, this method may affect the performance (but not accuracy) of other parsers which are being used concurrently. Annotations @Override

clearDFA

back to summary

public void clearDFA()

Overrides org.antlr.v4.runtime.atn.ATNSimulator.clearDFA.

Doc from org.antlr.v4.runtime.atn.ATNSimulator.clearDFA.

Clear the DFA cache used by the current instance. Since the DFA cache may be shared by multiple ATN simulators, this method may affect the performance (but not accuracy) of other parsers which are being used concurrently.

Annotations

@Override

closure back to summary

closure	back to summary
protected boolean closure(CharStream input, LexerATNConfig config, ATNConfigSet configs, boolean currentAltReachedAcceptState, boolean speculative, boolean treatEofAsEpsilon) Since the alternatives within any lexer decision are ordered by preference, this method stops pursuing the closure as soon as an accept state is reached. After the first accept state is reached by depth-first search from `config`, all other (potentially reachable) states for this rule would have a lower priority. Returns:boolean `true` if an accept state is reached, otherwise `false`.

protected boolean closure(CharStream input, LexerATNConfig config, ATNConfigSet configs, boolean currentAltReachedAcceptState, boolean speculative, boolean treatEofAsEpsilon)

Since the alternatives within any lexer decision are ordered by preference, this method stops pursuing the closure as soon as an accept state is reached. After the first accept state is reached by depth-first search from config, all other (potentially reachable) states for this rule would have a lower priority.

Returns:boolean: true if an accept state is reached, otherwise false.

computeStartState	back to summary
protected ATNConfigSet computeStartState(CharStream input, ATNState p)

computeTargetState back to summary

computeTargetState	back to summary
protected DFAState computeTargetState(CharStream input, DFAState s, int t) Compute a target state for an edge in the DFA, and attempt to add the computed state and corresponding edge to the DFA. Parameters input:CharStream The input stream s:DFAState The current DFA state t:int The next input symbol Returns:DFAState The computed target DFA state for the given input symbol `t`. If `t` does not lead to a valid DFA state, this method returns `ERROR`.

protected DFAState computeTargetState(CharStream input, DFAState s, int t)

Compute a target state for an edge in the DFA, and attempt to add the computed state and corresponding edge to the DFA.

Parameters

input:CharStream: The input stream
s:DFAState: The current DFA state
t:int: The next input symbol

Returns:DFAState

The computed target DFA state for the given input symbol t. If t does not lead to a valid DFA state, this method returns ERROR.

consume	back to summary
public void consume(CharStream input)

copyState	back to summary
public void copyState(LexerATNSimulator simulator)

evaluatePredicate back to summary

evaluatePredicate	back to summary
protected boolean evaluatePredicate(CharStream input, int ruleIndex, int predIndex, boolean speculative) Evaluate a predicate specified in the lexer. If `speculative` is `true`, this method was called before `consume` for the matched character. This method should call `consume` before evaluating the predicate to ensure position sensitive values, including `Lexer#getText`, `Lexer#getLine`, and `Lexer#getCharPositionInLine`, properly reflect the current lexer state. This method should restore `input` and the simulator to the original state before returning (i.e. undo the actions made by the call to `consume`. Parameters input:CharStream The input stream. ruleIndex:int The rule containing the predicate. predIndex:int The index of the predicate within the rule. speculative:boolean `true` if the current index in `input` is one character before the predicate's location. Returns:boolean `true` if the specified predicate evaluates to `true`.

protected boolean evaluatePredicate(CharStream input, int ruleIndex, int predIndex, boolean speculative)

Evaluate a predicate specified in the lexer.

If speculative is true, this method was called before consume for the matched character. This method should call consume before evaluating the predicate to ensure position sensitive values, including Lexer#getText, Lexer#getLine, and Lexer#getCharPositionInLine, properly reflect the current lexer state. This method should restore input and the simulator to the original state before returning (i.e. undo the actions made by the call to consume.

Parameters

input:CharStream: The input stream.
ruleIndex:int: The rule containing the predicate.
predIndex:int: The index of the predicate within the rule.
speculative:boolean: true if the current index in input is one character before the predicate's location.

Returns:boolean

true if the specified predicate evaluates to true.

execATN	back to summary
protected int execATN(CharStream input, DFAState ds0)

failOrAccept	back to summary
protected int failOrAccept(LexerATNSimulator.SimState prevAccept, CharStream input, ATNConfigSet reach, int t)

getCharPositionInLine	back to summary
public int getCharPositionInLine()

getDFA	back to summary
public final DFA getDFA(int mode)

getEpsilonTarget	back to summary
protected LexerATNConfig getEpsilonTarget(CharStream input, LexerATNConfig config, Transition t, ATNConfigSet configs, boolean speculative, boolean treatEofAsEpsilon)

getExistingTargetState back to summary

getExistingTargetState	back to summary
protected DFAState getExistingTargetState(DFAState s, int t) Get an existing target state for an edge in the DFA. If the target state for the edge has not yet been computed or is otherwise not available, this method returns `null`. Parameters s:DFAState The current DFA state t:int The next input symbol Returns:DFAState The existing target DFA state for the given input symbol `t`, or `null` if the target state for this edge is not already cached

protected DFAState getExistingTargetState(DFAState s, int t)

Get an existing target state for an edge in the DFA. If the target state for the edge has not yet been computed or is otherwise not available, this method returns null.

Parameters

s:DFAState: The current DFA state
t:int: The next input symbol

Returns:DFAState

The existing target DFA state for the given input symbol t, or null if the target state for this edge is not already cached

getLine	back to summary
public int getLine()

getReachableConfigSet	back to summary
protected void getReachableConfigSet(CharStream input, ATNConfigSet closure, ATNConfigSet reach, int t) Given a starting configuration set, figure out all ATN configurations we can reach upon input `t`. Parameter `reach` is a return parameter.

getReachableTarget	back to summary
protected ATNState getReachableTarget(Transition trans, int t)

getText	back to summary
public String getText(CharStream input) Get the text matched so far for the current token.

getTokenName	back to summary
public String getTokenName(int t)

match	back to summary
public int match(CharStream input, int mode)

matchATN	back to summary
protected int matchATN(CharStream input)

reset	back to summary
public void reset() Implements abstract org.antlr.v4.runtime.atn.ATNSimulator.reset. Annotations @Override

reset

back to summary

public void reset()

Implements abstract org.antlr.v4.runtime.atn.ATNSimulator.reset.

Annotations

@Override

setCharPositionInLine	back to summary
public void setCharPositionInLine(int charPositionInLine)

setLine	back to summary
public void setLine(int line)

org.antlr.v4.runtime.atn back to summary

protected Class LexerATNSimulator.SimState

Class Inheritance

extends Object

java.lang.Object
org.antlr.v4.runtime.atn.LexerATNSimulator.SimState

When we hit an accept state in either the DFA or the ATN, we have to notify the character stream to start buffering characters via IntStream#mark and record the current state. The current sim state includes the current index into the input, the current line, and current character position in that line. Note that the Lexer is tracking the starting line and characterization of the token. These variables track the "state" of the simulator when it hits an accept state.

We track these variables separately for the DFA and ATN simulation because the DFA simulation often has to fail over to the ATN simulation. If the ATN simulation fails, we need the DFA to fall back to its previously accepted state, if any. If the ATN succeeds, then the ATN does the accept and the DFA simulator that invoked it can simply return the predicted token type.

Field Summary

Modifier and Type	Field and Description
protected int	charPos
protected DFAState	dfaState
protected int	index
protected int	line

Constructor Summary

Access	Constructor and Description
protected	SimState()

Method Summary

Modifier and Type	Method and Description
protected void	reset()

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

Field Detail

charPos	back to summary
protected int charPos

dfaState	back to summary
protected DFAState dfaState

index	back to summary
protected int index

line	back to summary
protected int line

Constructor Detail

SimState	back to summary
protected SimState()

Method Detail

reset	back to summary
protected void reset()

public Class LexerATNSimulator

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

protected Class LexerATNSimulator.SimState

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail