org.antlr.v4.runtime.atn

Class LexerATNSimulator

java.lang.Object

org.antlr.v4.runtime.atn.ATNSimulator

org.antlr.v4.runtime.atn.LexerATNSimulator

public class LexerATNSimulator
extends ATNSimulator

"dup" of ParserInterpreter

Nested Class Summary

Nested Classes

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.

Field Summary

Fields

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

Fields inherited from class org.antlr.v4.runtime.atn.ATNSimulator

atn, ERROR, SERIALIZED_UUID, SERIALIZED_VERSION, sharedContextCache

Constructor Summary

Constructors

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

Method Summary

Methods

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)
void	clearDFA() Clear the DFA cache used by the current instance.
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.
protected ATNConfigSet	computeStartState(CharStream input, ATNState p)
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.
void	consume(CharStream input)
void	copyState(LexerATNSimulator simulator)
protected boolean	evaluatePredicate(CharStream input, int ruleIndex, int predIndex, boolean 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)
int	getCharPositionInLine()
DFA	getDFA(int mode)
protected LexerATNConfig	getEpsilonTarget(CharStream input, LexerATNConfig config, Transition t, ATNConfigSet configs, boolean speculative, boolean treatEofAsEpsilon)
protected DFAState	getExistingTargetState(DFAState s, int t) Get an existing target state for an edge in the DFA.
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)
String	getText(CharStream input) Get the text matched so far for the current token.
String	getTokenName(int t)
int	match(CharStream input, int mode)
protected int	matchATN(CharStream input)
void	reset()
void	setCharPositionInLine(int charPositionInLine)
void	setLine(int line)

Methods inherited from class org.antlr.v4.runtime.atn.ATNSimulator

checkCondition, checkCondition, deserialize, edgeFactory, getCachedContext, getSharedContextCache, stateFactory, toInt, toInt32, toLong, toUUID

Methods inherited from class java.lang.Object

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

Field Detail

debug

public static final boolean debug

See Also:

Constant Field Values

dfa_debug

public static final boolean dfa_debug

See Also:

Constant Field Values

MIN_DFA_EDGE

public static final int MIN_DFA_EDGE

See Also:

Constant Field Values

MAX_DFA_EDGE

public static final int MAX_DFA_EDGE

See Also:

Constant Field Values

recog

protected final Lexer recog

startIndex

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.

line

protected int line

line number 1..n within the input

charPositionInLine

protected int charPositionInLine

The index of the character relative to the beginning of the line 0..n-1

decisionToDFA

public final DFA[] decisionToDFA

mode

protected int mode

prevAccept

protected final LexerATNSimulator.SimState prevAccept

Used during DFA/ATN exec to record the most recent accept configuration info

Constructor Detail

LexerATNSimulator

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

LexerATNSimulator

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

Method Detail

copyState

public void copyState(LexerATNSimulator simulator)

match

public int match(CharStream input,
        int mode)

reset

public void reset()

Specified by:

reset in class ATNSimulator

clearDFA

public void clearDFA()

Description copied from class: ATNSimulator

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.

Overrides:

clearDFA in class ATNSimulator

matchATN

protected int matchATN(CharStream input)

execATN

protected int execATN(CharStream input,
          DFAState ds0)

getExistingTargetState

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 - The current DFA state

t - The next input symbol

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

computeTargetState

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 - The input stream

s - The current DFA state

t - The next input symbol

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 ATNSimulator.ERROR.

failOrAccept

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

getReachableConfigSet

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.

accept

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

getReachableTarget

protected ATNState getReachableTarget(Transition trans,
                          int t)

computeStartState

protected ATNConfigSet computeStartState(CharStream input,
                             ATNState p)

closure

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:

true if an accept state is reached, otherwise false.

getEpsilonTarget

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

evaluatePredicate

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(org.antlr.v4.runtime.CharStream) for the matched character. This method should call consume(org.antlr.v4.runtime.CharStream) 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(org.antlr.v4.runtime.CharStream).

Parameters:

input - The input stream.

ruleIndex - The rule containing the predicate.

predIndex - The index of the predicate within the rule.

speculative - true if the current index in input is one character before the predicate's location.

Returns:

true if the specified predicate evaluates to true.

captureSimState

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

addDFAEdge

protected DFAState addDFAEdge(DFAState from,
                  int t,
                  ATNConfigSet q)

addDFAEdge

protected void addDFAEdge(DFAState p,
              int t,
              DFAState q)

addDFAState

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.

getDFA

public final DFA getDFA(int mode)

getText

public String getText(CharStream input)

Get the text matched so far for the current token.

getLine

public int getLine()

setLine

public void setLine(int line)

getCharPositionInLine

public int getCharPositionInLine()

setCharPositionInLine

public void setCharPositionInLine(int charPositionInLine)

consume

public void consume(CharStream input)

getTokenName

public String getTokenName(int t)