Examples with ATNConfigSet org.antlr.v4.runtime.atn.ATNConfigSet used on opensource projects

Example 16 with ATNConfigSet

use of org.antlr.v4.runtime.atn.ATNConfigSet in project antlr4 by tunnelvisionlabs.

the class ParserATNSimulator method addDFAState.

/**
 * See comment on LexerInterpreter.addDFAState.
 */
@NotNull
protected DFAState addDFAState(@NotNull DFA dfa, @NotNull ATNConfigSet configs, PredictionContextCache contextCache) {
    final boolean enableDfa = enable_global_context_dfa || !configs.isOutermostConfigSet();
    if (enableDfa) {
        if (!configs.isReadOnly()) {
            configs.optimizeConfigs(this);
        }
        DFAState proposed = createDFAState(dfa, configs);
        DFAState existing = dfa.states.get(proposed);
        if (existing != null)
            return existing;
    }
    if (!configs.isReadOnly()) {
        if (configs.getConflictInfo() == null) {
            configs.setConflictInfo(isConflicted(configs, contextCache));
        }
    }
    DFAState newState = createDFAState(dfa, configs.clone(true));
    DecisionState decisionState = atn.getDecisionState(dfa.decision);
    int predictedAlt = getUniqueAlt(configs);
    if (predictedAlt != ATN.INVALID_ALT_NUMBER) {
        newState.setAcceptState(new AcceptStateInfo(predictedAlt));
    } else if (configs.getConflictingAlts() != null) {
        newState.setAcceptState(new AcceptStateInfo(newState.configs.getConflictingAlts().nextSetBit(0)));
    }
    if (newState.isAcceptState() && configs.hasSemanticContext()) {
        predicateDFAState(newState, configs, decisionState.getNumberOfTransitions());
    }
    if (!enableDfa) {
        return newState;
    }
    DFAState added = dfa.addState(newState);
    if (debug && added == newState)
        System.out.println("adding new DFA state: " + newState);
    return added;
}

Example 17 with ATNConfigSet

use of org.antlr.v4.runtime.atn.ATNConfigSet in project antlr4 by tunnelvisionlabs.

the class ParserATNSimulator method computeTargetState.

/**
 * Compute a target state for an edge in the DFA, and attempt to add the
 * computed state and corresponding edge to the DFA.
 *
 * @param dfa
 * @param s The current DFA state
 * @param remainingGlobalContext
 * @param t The next input symbol
 * @param useContext
 * @param contextCache
 *
 * @return The computed target DFA state for the given input symbol
 * {@code t}. If {@code t} does not lead to a valid DFA state, this method
 * returns {@link #ERROR}.
 */
@NotNull
protected Tuple2<DFAState, ParserRuleContext> computeTargetState(@NotNull DFA dfa, @NotNull DFAState s, ParserRuleContext remainingGlobalContext, int t, boolean useContext, PredictionContextCache contextCache) {
    List<ATNConfig> closureConfigs = new ArrayList<ATNConfig>(s.configs);
    IntegerList contextElements = null;
    ATNConfigSet reach = new ATNConfigSet();
    boolean stepIntoGlobal;
    do {
        boolean hasMoreContext = !useContext || remainingGlobalContext != null;
        if (!hasMoreContext) {
            reach.setOutermostConfigSet(true);
        }
        ATNConfigSet reachIntermediate = new ATNConfigSet();
        /* Configurations already in a rule stop state indicate reaching the end
			 * of the decision rule (local context) or end of the start rule (full
			 * context). Once reached, these configurations are never updated by a
			 * closure operation, so they are handled separately for the performance
			 * advantage of having a smaller intermediate set when calling closure.
			 *
			 * For full-context reach operations, separate handling is required to
			 * ensure that the alternative matching the longest overall sequence is
			 * chosen when multiple such configurations can match the input.
			 */
        List<ATNConfig> skippedStopStates = null;
        for (ATNConfig c : closureConfigs) {
            if (debug)
                System.out.println("testing " + getTokenName(t) + " at " + c.toString());
            if (c.getState() instanceof RuleStopState) {
                assert c.getContext().isEmpty();
                if (useContext && !c.getReachesIntoOuterContext() || t == IntStream.EOF) {
                    if (skippedStopStates == null) {
                        skippedStopStates = new ArrayList<ATNConfig>();
                    }
                    skippedStopStates.add(c);
                }
                continue;
            }
            int n = c.getState().getNumberOfOptimizedTransitions();
            for (int ti = 0; ti < n; ti++) {
                // for each optimized transition
                Transition trans = c.getState().getOptimizedTransition(ti);
                ATNState target = getReachableTarget(c, trans, t);
                if (target != null) {
                    reachIntermediate.add(c.transform(target, false), contextCache);
                }
            }
        }
        /* This block optimizes the reach operation for intermediate sets which
			 * trivially indicate a termination state for the overall
			 * adaptivePredict operation.
			 *
			 * The conditions assume that intermediate
			 * contains all configurations relevant to the reach set, but this
			 * condition is not true when one or more configurations have been
			 * withheld in skippedStopStates, or when the current symbol is EOF.
			 */
        if (optimize_unique_closure && skippedStopStates == null && t != Token.EOF && reachIntermediate.getUniqueAlt() != ATN.INVALID_ALT_NUMBER) {
            reachIntermediate.setOutermostConfigSet(reach.isOutermostConfigSet());
            reach = reachIntermediate;
            break;
        }
        /* If the reach set could not be trivially determined, perform a closure
			 * operation on the intermediate set to compute its initial value.
			 */
        final boolean collectPredicates = false;
        boolean treatEofAsEpsilon = t == Token.EOF;
        closure(reachIntermediate, reach, collectPredicates, hasMoreContext, contextCache, treatEofAsEpsilon);
        stepIntoGlobal = reach.getDipsIntoOuterContext();
        if (t == IntStream.EOF) {
            /* After consuming EOF no additional input is possible, so we are
				 * only interested in configurations which reached the end of the
				 * decision rule (local context) or end of the start rule (full
				 * context). Update reach to contain only these configurations. This
				 * handles both explicit EOF transitions in the grammar and implicit
				 * EOF transitions following the end of the decision or start rule.
				 *
				 * This is handled before the configurations in skippedStopStates,
				 * because any configurations potentially added from that list are
				 * already guaranteed to meet this condition whether or not it's
				 * required.
				 */
            reach = removeAllConfigsNotInRuleStopState(reach, contextCache);
        }
        /* If skippedStopStates is not null, then it contains at least one
			 * configuration. For full-context reach operations, these
			 * configurations reached the end of the start rule, in which case we
			 * only add them back to reach if no configuration during the current
			 * closure operation reached such a state. This ensures adaptivePredict
			 * chooses an alternative matching the longest overall sequence when
			 * multiple alternatives are viable.
			 */
        if (skippedStopStates != null && (!useContext || !PredictionMode.hasConfigInRuleStopState(reach))) {
            assert !skippedStopStates.isEmpty();
            for (ATNConfig c : skippedStopStates) {
                reach.add(c, contextCache);
            }
        }
        if (useContext && stepIntoGlobal) {
            reach.clear();
            remainingGlobalContext = skipTailCalls(remainingGlobalContext);
            int nextContextElement = getReturnState(remainingGlobalContext);
            if (contextElements == null) {
                contextElements = new IntegerList();
            }
            if (remainingGlobalContext.isEmpty()) {
                remainingGlobalContext = null;
            } else {
                remainingGlobalContext = remainingGlobalContext.getParent();
            }
            contextElements.add(nextContextElement);
            if (nextContextElement != PredictionContext.EMPTY_FULL_STATE_KEY) {
                for (int i = 0; i < closureConfigs.size(); i++) {
                    closureConfigs.set(i, closureConfigs.get(i).appendContext(nextContextElement, contextCache));
                }
            }
        }
    } while (useContext && stepIntoGlobal);
    if (reach.isEmpty()) {
        addDFAEdge(s, t, ERROR);
        return Tuple.create(ERROR, remainingGlobalContext);
    }
    DFAState result = addDFAEdge(dfa, s, t, contextElements, reach, contextCache);
    return Tuple.create(result, remainingGlobalContext);
}

Example 18 with ATNConfigSet

use of org.antlr.v4.runtime.atn.ATNConfigSet in project antlr4 by tunnelvisionlabs.

the class ParserATNSimulator method reportAmbiguity.

/**
 * If context sensitive parsing, we know it's ambiguity not conflict
 */
protected void reportAmbiguity(@NotNull DFA dfa, // the DFA state from execATN() that had SLL conflicts
DFAState D, int startIndex, int stopIndex, boolean exact, @NotNull BitSet ambigAlts, // configs that LL not SLL considered conflicting
@NotNull ATNConfigSet configs) {
    if (debug || retry_debug) {
        Interval interval = Interval.of(startIndex, stopIndex);
        System.out.println("reportAmbiguity " + ambigAlts + ":" + configs + ", input=" + parser.getInputStream().getText(interval));
    }
    if (parser != null)
        parser.getErrorListenerDispatch().reportAmbiguity(parser, dfa, startIndex, stopIndex, exact, ambigAlts, configs);
}

Example 19 with ATNConfigSet

use of org.antlr.v4.runtime.atn.ATNConfigSet in project antlr4 by tunnelvisionlabs.

the class LexerATNSimulator method addDFAState.

/**
 * 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.
 */
@NotNull
protected DFAState addDFAState(@NotNull ATNConfigSet configs) {
    /* the lexer evaluates predicates on-the-fly; by this point configs
		 * should not contain any configurations with unevaluated predicates.
		 */
    assert !configs.hasSemanticContext();
    DFAState proposed = new DFAState(atn.modeToDFA[mode], configs);
    DFAState existing = atn.modeToDFA[mode].states.get(proposed);
    if (existing != null)
        return existing;
    configs.optimizeConfigs(this);
    DFAState newState = new DFAState(atn.modeToDFA[mode], configs.clone(true));
    ATNConfig firstConfigWithRuleStopState = null;
    for (ATNConfig c : configs) {
        if (c.getState() instanceof RuleStopState) {
            firstConfigWithRuleStopState = c;
            break;
        }
    }
    if (firstConfigWithRuleStopState != null) {
        int prediction = atn.ruleToTokenType[firstConfigWithRuleStopState.getState().ruleIndex];
        LexerActionExecutor lexerActionExecutor = firstConfigWithRuleStopState.getLexerActionExecutor();
        newState.setAcceptState(new AcceptStateInfo(prediction, lexerActionExecutor));
    }
    return atn.modeToDFA[mode].addState(newState);
}

Example 20 with ATNConfigSet

use of org.antlr.v4.runtime.atn.ATNConfigSet in project antlr4 by tunnelvisionlabs.

the class LexerATNSimulator method matchATN.

protected int matchATN(@NotNull CharStream input) {
    ATNState startState = atn.modeToStartState.get(mode);
    if (debug) {
        System.out.format(Locale.getDefault(), "matchATN mode %d start: %s\n", mode, startState);
    }
    int old_mode = mode;
    ATNConfigSet s0_closure = computeStartState(input, startState);
    boolean suppressEdge = s0_closure.hasSemanticContext();
    if (suppressEdge) {
        s0_closure.clearExplicitSemanticContext();
    }
    DFAState next = addDFAState(s0_closure);
    if (!suppressEdge) {
        if (!atn.modeToDFA[mode].s0.compareAndSet(null, next)) {
            next = atn.modeToDFA[mode].s0.get();
        }
    }
    int predict = execATN(input, next);
    if (debug) {
        System.out.format(Locale.getDefault(), "DFA after matchATN: %s\n", atn.modeToDFA[old_mode].toLexerString());
    }
    return predict;
}