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

Example 1 with Transition

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

the class TestAmbigParseTrees method testInterpAtSpecificAlt.

void testInterpAtSpecificAlt(LexerGrammar lg, Grammar g, String startRule, int startAlt, String input, String expectedParseTree) {
    LexerInterpreter lexEngine = lg.createLexerInterpreter(CharStreams.fromString(input));
    CommonTokenStream tokens = new CommonTokenStream(lexEngine);
    ParserInterpreter parser = g.createGrammarParserInterpreter(tokens);
    RuleStartState ruleStartState = g.atn.ruleToStartState[g.getRule(startRule).index];
    Transition tr = ruleStartState.transition(0);
    ATNState t2 = tr.target;
    if (!(t2 instanceof BasicBlockStartState)) {
        throw new IllegalArgumentException("rule has no decision: " + startRule);
    }
    parser.addDecisionOverride(((DecisionState) t2).decision, 0, startAlt);
    ParseTree t = parser.parse(g.rules.get(startRule).index);
    InterpreterTreeTextProvider nodeTextProvider = new InterpreterTreeTextProvider(g.getRuleNames());
    assertEquals(expectedParseTree, Trees.toStringTree(t, nodeTextProvider));
}

Example 2 with Transition

use of org.antlr.v4.runtime.atn.Transition 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 3 with Transition

use of org.antlr.v4.runtime.atn.Transition 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 4 with Transition

use of org.antlr.v4.runtime.atn.Transition 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 5 with Transition

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

the class LexerATNFactory method set.

@Override
public Handle set(GrammarAST associatedAST, List<GrammarAST> alts, boolean invert) {
    ATNState left = newState(associatedAST);
    ATNState right = newState(associatedAST);
    IntervalSet set = new IntervalSet();
    for (GrammarAST t : alts) {
        if (t.getType() == ANTLRParser.RANGE) {
            int a = CharSupport.getCharValueFromGrammarCharLiteral(t.getChild(0).getText());
            int b = CharSupport.getCharValueFromGrammarCharLiteral(t.getChild(1).getText());
            if (checkRange((GrammarAST) t.getChild(0), (GrammarAST) t.getChild(1), a, b)) {
                checkSetCollision(associatedAST, set, a, b);
                set.add(a, b);
            }
        } else if (t.getType() == ANTLRParser.LEXER_CHAR_SET) {
            set.addAll(getSetFromCharSetLiteral(t));
        } else if (t.getType() == ANTLRParser.STRING_LITERAL) {
            int c = CharSupport.getCharValueFromGrammarCharLiteral(t.getText());
            if (c != -1) {
                checkSetCollision(associatedAST, set, c);
                set.add(c);
            } else {
                g.tool.errMgr.grammarError(ErrorType.INVALID_LITERAL_IN_LEXER_SET, g.fileName, t.getToken(), t.getText());
            }
        } else if (t.getType() == ANTLRParser.TOKEN_REF) {
            g.tool.errMgr.grammarError(ErrorType.UNSUPPORTED_REFERENCE_IN_LEXER_SET, g.fileName, t.getToken(), t.getText());
        }
    }
    if (invert) {
        left.addTransition(new NotSetTransition(right, set));
    } else {
        Transition transition;
        if (set.getIntervals().size() == 1) {
            Interval interval = set.getIntervals().get(0);
            transition = CodePointTransitions.createWithCodePointRange(right, interval.a, interval.b);
        } else {
            transition = new SetTransition(right, set);
        }
        left.addTransition(transition);
    }
    associatedAST.atnState = left;
    return new Handle(left, right);
}