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

Example 1 with BlockEndState

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

the class ATNOptimizer method optimizeSets.

private static void optimizeSets(Grammar g, ATN atn) {
    if (g.isParser()) {
        // parser codegen doesn't currently support SetTransition
        return;
    }
    int removedStates = 0;
    List<DecisionState> decisions = atn.decisionToState;
    for (DecisionState decision : decisions) {
        if (decision.ruleIndex >= 0) {
            Rule rule = g.getRule(decision.ruleIndex);
            if (Character.isLowerCase(rule.name.charAt(0))) {
                // parser codegen doesn't currently support SetTransition
                continue;
            }
        }
        IntervalSet setTransitions = new IntervalSet();
        for (int i = 0; i < decision.getNumberOfTransitions(); i++) {
            Transition epsTransition = decision.transition(i);
            if (!(epsTransition instanceof EpsilonTransition)) {
                continue;
            }
            if (epsTransition.target.getNumberOfTransitions() != 1) {
                continue;
            }
            Transition transition = epsTransition.target.transition(0);
            if (!(transition.target instanceof BlockEndState)) {
                continue;
            }
            if (transition instanceof NotSetTransition) {
                // TODO: not yet implemented
                continue;
            }
            if (transition instanceof AtomTransition || transition instanceof RangeTransition || transition instanceof SetTransition) {
                setTransitions.add(i);
            }
        }
        // due to min alt resolution policies, can only collapse sequential alts
        for (int i = setTransitions.getIntervals().size() - 1; i >= 0; i--) {
            Interval interval = setTransitions.getIntervals().get(i);
            if (interval.length() <= 1) {
                continue;
            }
            ATNState blockEndState = decision.transition(interval.a).target.transition(0).target;
            IntervalSet matchSet = new IntervalSet();
            for (int j = interval.a; j <= interval.b; j++) {
                Transition matchTransition = decision.transition(j).target.transition(0);
                if (matchTransition instanceof NotSetTransition) {
                    throw new UnsupportedOperationException("Not yet implemented.");
                }
                IntervalSet set = matchTransition.label();
                List<Interval> intervals = set.getIntervals();
                int n = intervals.size();
                for (int k = 0; k < n; k++) {
                    Interval setInterval = intervals.get(k);
                    int a = setInterval.a;
                    int b = setInterval.b;
                    if (a != -1 && b != -1) {
                        for (int v = a; v <= b; v++) {
                            if (matchSet.contains(v)) {
                                // TODO: Token is missing (i.e. position in source will not be displayed).
                                g.tool.errMgr.grammarError(ErrorType.CHARACTERS_COLLISION_IN_SET, g.fileName, null, CharSupport.getANTLRCharLiteralForChar(v), CharSupport.getIntervalSetEscapedString(matchSet));
                                break;
                            }
                        }
                    }
                }
                matchSet.addAll(set);
            }
            Transition newTransition;
            if (matchSet.getIntervals().size() == 1) {
                if (matchSet.size() == 1) {
                    newTransition = CodePointTransitions.createWithCodePoint(blockEndState, matchSet.getMinElement());
                } else {
                    Interval matchInterval = matchSet.getIntervals().get(0);
                    newTransition = CodePointTransitions.createWithCodePointRange(blockEndState, matchInterval.a, matchInterval.b);
                }
            } else {
                newTransition = new SetTransition(blockEndState, matchSet);
            }
            decision.transition(interval.a).target.setTransition(0, newTransition);
            for (int j = interval.a + 1; j <= interval.b; j++) {
                Transition removed = decision.removeTransition(interval.a + 1);
                atn.removeState(removed.target);
                removedStates++;
            }
        }
    }
// System.out.println("ATN optimizer removed " + removedStates + " states by collapsing sets.");
}

Example 2 with BlockEndState

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

the class LL1Analyzer method LOOK.

/**
 * Compute set of tokens that can follow {@code s} in the ATN in the
 * specified {@code ctx}.
 *
 * <p>If {@code ctx} is {@code null} and the end of the rule containing
 * {@code s} is reached, {@link Token#EPSILON} is added to the result set.
 * If {@code ctx} is not {@code null} and the end of the outermost rule is
 * reached, {@link Token#EOF} is added to the result set.</p>
 *
 * @param s the ATN state
 * @param stopState the ATN state to stop at. This can be a
 * {@link BlockEndState} to detect epsilon paths through a closure.
 * @param ctx the complete parser context, or {@code null} if the context
 * should be ignored
 *
 * @return The set of tokens that can follow {@code s} in the ATN in the
 * specified {@code ctx}.
 */
public IntervalSet LOOK(ATNState s, ATNState stopState, RuleContext ctx) {
    IntervalSet r = new IntervalSet();
    // ignore preds; get all lookahead
    boolean seeThruPreds = true;
    PredictionContext lookContext = ctx != null ? PredictionContext.fromRuleContext(s.atn, ctx) : null;
    _LOOK(s, stopState, lookContext, r, new HashSet<ATNConfig>(), new BitSet(), seeThruPreds, true);
    return r;
}

Example 3 with BlockEndState

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

the class ATNOptimizer method optimizeSets.

private static void optimizeSets(Grammar g, ATN atn) {
    if (g.isParser()) {
        // parser codegen doesn't currently support SetTransition
        return;
    }
    int removedStates = 0;
    List<DecisionState> decisions = atn.decisionToState;
    for (DecisionState decision : decisions) {
        if (decision.ruleIndex >= 0) {
            Rule rule = g.getRule(decision.ruleIndex);
            if (Character.isLowerCase(rule.name.charAt(0))) {
                // parser codegen doesn't currently support SetTransition
                continue;
            }
        }
        IntervalSet setTransitions = new IntervalSet();
        for (int i = 0; i < decision.getNumberOfTransitions(); i++) {
            Transition epsTransition = decision.transition(i);
            if (!(epsTransition instanceof EpsilonTransition)) {
                continue;
            }
            if (epsTransition.target.getNumberOfTransitions() != 1) {
                continue;
            }
            Transition transition = epsTransition.target.transition(0);
            if (!(transition.target instanceof BlockEndState)) {
                continue;
            }
            if (transition instanceof NotSetTransition) {
                // TODO: not yet implemented
                continue;
            }
            if (transition instanceof AtomTransition || transition instanceof RangeTransition || transition instanceof SetTransition) {
                setTransitions.add(i);
            }
        }
        // due to min alt resolution policies, can only collapse sequential alts
        for (int i = setTransitions.getIntervals().size() - 1; i >= 0; i--) {
            Interval interval = setTransitions.getIntervals().get(i);
            if (interval.length() <= 1) {
                continue;
            }
            ATNState blockEndState = decision.transition(interval.a).target.transition(0).target;
            IntervalSet matchSet = new IntervalSet();
            for (int j = interval.a; j <= interval.b; j++) {
                Transition matchTransition = decision.transition(j).target.transition(0);
                if (matchTransition instanceof NotSetTransition) {
                    throw new UnsupportedOperationException("Not yet implemented.");
                }
                IntervalSet set = matchTransition.label();
                List<Interval> intervals = set.getIntervals();
                int n = intervals.size();
                for (int k = 0; k < n; k++) {
                    Interval setInterval = intervals.get(k);
                    int a = setInterval.a;
                    int b = setInterval.b;
                    if (a != -1 && b != -1) {
                        for (int v = a; v <= b; v++) {
                            if (matchSet.contains(v)) {
                                // TODO: Token is missing (i.e. position in source will not be displayed).
                                g.tool.errMgr.grammarError(ErrorType.CHARACTERS_COLLISION_IN_SET, g.fileName, null, CharSupport.getANTLRCharLiteralForChar(v), CharSupport.getIntervalSetEscapedString(matchSet));
                                break;
                            }
                        }
                    }
                }
                matchSet.addAll(set);
            }
            Transition newTransition;
            if (matchSet.getIntervals().size() == 1) {
                if (matchSet.size() == 1) {
                    newTransition = CodePointTransitions.createWithCodePoint(blockEndState, matchSet.getMinElement());
                } else {
                    Interval matchInterval = matchSet.getIntervals().get(0);
                    newTransition = CodePointTransitions.createWithCodePointRange(blockEndState, matchInterval.a, matchInterval.b);
                }
            } else {
                newTransition = new SetTransition(blockEndState, matchSet);
            }
            decision.transition(interval.a).target.setTransition(0, newTransition);
            for (int j = interval.a + 1; j <= interval.b; j++) {
                Transition removed = decision.removeTransition(interval.a + 1);
                atn.removeState(removed.target);
                removedStates++;
            }
        }
    }
// System.out.println("ATN optimizer removed " + removedStates + " states by collapsing sets.");
}

Example 4 with BlockEndState

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

the class ParserATNFactory method star.

/**
 * From {@code (blk)*} build {@code ( blk+ )?} with *two* decisions, one for
 * entry and one for choosing alts of {@code blk}.
 *
 * <pre>
 *   |-------------|
 *   v             |
 *   o--[o-blk-o]-&gt;o  o
 *   |                ^
 *   -----------------|
 * </pre>
 *
 * Note that the optional bypass must jump outside the loop as
 * {@code (A|B)*} is not the same thing as {@code (A|B|)+}.
 */
@Override
public Handle star(GrammarAST starAST, Handle elem) {
    StarBlockStartState blkStart = (StarBlockStartState) elem.left;
    BlockEndState blkEnd = (BlockEndState) elem.right;
    preventEpsilonClosureBlocks.add(new Triple<Rule, ATNState, ATNState>(currentRule, blkStart, blkEnd));
    StarLoopEntryState entry = newState(StarLoopEntryState.class, starAST);
    entry.nonGreedy = !((QuantifierAST) starAST).isGreedy();
    atn.defineDecisionState(entry);
    LoopEndState end = newState(LoopEndState.class, starAST);
    StarLoopbackState loop = newState(StarLoopbackState.class, starAST);
    entry.loopBackState = loop;
    end.loopBackState = loop;
    BlockAST blkAST = (BlockAST) starAST.getChild(0);
    if (((QuantifierAST) starAST).isGreedy()) {
        if (expectNonGreedy(blkAST)) {
            g.tool.errMgr.grammarError(ErrorType.EXPECTED_NON_GREEDY_WILDCARD_BLOCK, g.fileName, starAST.getToken(), starAST.getToken().getText());
        }
        // loop enter edge (alt 1)
        epsilon(entry, blkStart);
        // bypass loop edge (alt 2)
        epsilon(entry, end);
    } else {
        // if not greedy, priority to exit branch; make it first
        // bypass loop edge (alt 1)
        epsilon(entry, end);
        // loop enter edge (alt 2)
        epsilon(entry, blkStart);
    }
    // block end hits loop back
    epsilon(blkEnd, loop);
    // loop back to entry/exit decision
    epsilon(loop, entry);
    // decision is to enter/exit; blk is its own decision
    starAST.atnState = entry;
    return new Handle(entry, end);
}

Example 5 with BlockEndState

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

the class LL1Analyzer method LOOK.

/**
 * Compute set of tokens that can follow {@code s} in the ATN in the
 * specified {@code ctx}.
 *
 * <p>If {@code ctx} is {@code null} and the end of the rule containing
 * {@code s} is reached, {@link Token#EPSILON} is added to the result set.
 * If {@code ctx} is not {@code PredictionContext#EMPTY_LOCAL} and the end of the outermost rule is
 * reached, {@link Token#EOF} is added to the result set.</p>
 *
 * @param s the ATN state
 * @param stopState the ATN state to stop at. This can be a
 * {@link BlockEndState} to detect epsilon paths through a closure.
 * @param ctx the complete parser context, or {@code null} if the context
 * should be ignored
 *
 * @return The set of tokens that can follow {@code s} in the ATN in the
 * specified {@code ctx}.
 */
@NotNull
public IntervalSet LOOK(@NotNull ATNState s, @Nullable ATNState stopState, @NotNull PredictionContext ctx) {
    IntervalSet r = new IntervalSet();
    // ignore preds; get all lookahead
    final boolean seeThruPreds = true;
    final boolean addEOF = true;
    _LOOK(s, stopState, ctx, r, new HashSet<ATNConfig>(), new BitSet(), seeThruPreds, addEOF);
    return r;
}