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

Example 11 with ATNState

use of org.antlr.v4.runtime.atn.ATNState 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 12 with ATNState

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

the class LexerATNFactory method stringLiteral.

/**
 * For a lexer, a string is a sequence of char to match.  That is,
 *  "fog" is treated as 'f' 'o' 'g' not as a single transition in
 *  the DFA.  Machine== o-'f'->o-'o'->o-'g'->o and has n+1 states
 *  for n characters.
 */
@Override
public Handle stringLiteral(TerminalAST stringLiteralAST) {
    String chars = stringLiteralAST.getText();
    ATNState left = newState(stringLiteralAST);
    ATNState right;
    String s = CharSupport.getStringFromGrammarStringLiteral(chars);
    if (s == null) {
        // the lexer will already have given an error
        return new Handle(left, left);
    }
    int n = s.length();
    ATNState prev = left;
    right = null;
    for (int i = 0; i < n; ) {
        right = newState(stringLiteralAST);
        int codePoint = s.codePointAt(i);
        prev.addTransition(CodePointTransitions.createWithCodePoint(right, codePoint));
        prev = right;
        i += Character.charCount(codePoint);
    }
    stringLiteralAST.atnState = left;
    return new Handle(left, right);
}

Example 13 with ATNState

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

the class LexerATNFactory method charSetLiteral.

/**
 * [Aa\t \u1234a-z\]\p{Letter}\-] char sets
 */
@Override
public Handle charSetLiteral(GrammarAST charSetAST) {
    ATNState left = newState(charSetAST);
    ATNState right = newState(charSetAST);
    IntervalSet set = getSetFromCharSetLiteral(charSetAST);
    left.addTransition(new SetTransition(right, set));
    charSetAST.atnState = left;
    return new Handle(left, right);
}

Example 14 with ATNState

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

the class LexerATNFactory method tokenRef.

@Override
public Handle tokenRef(TerminalAST node) {
    // Ref to EOF in lexer yields char transition on -1
    if (node.getText().equals("EOF")) {
        ATNState left = newState(node);
        ATNState right = newState(node);
        left.addTransition(new AtomTransition(right, IntStream.EOF));
        return new Handle(left, right);
    }
    return _ruleRef(node);
}

Example 15 with ATNState

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

the class LexerATNFactory method range.

@Override
public Handle range(GrammarAST a, GrammarAST b) {
    ATNState left = newState(a);
    ATNState right = newState(b);
    int t1 = CharSupport.getCharValueFromGrammarCharLiteral(a.getText());
    int t2 = CharSupport.getCharValueFromGrammarCharLiteral(b.getText());
    checkRange(a, b, t1, t2);
    left.addTransition(CodePointTransitions.createWithCodePointRange(right, t1, t2));
    a.atnState = left;
    b.atnState = left;
    return new Handle(left, right);
}