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

Example 56 with ATNState

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

the class ParserATNFactory method addRuleFollowLinks.

public void addRuleFollowLinks() {
    for (ATNState p : atn.states) {
        if (p != null && p.getStateType() == ATNState.BASIC && p.getNumberOfTransitions() == 1 && p.transition(0) instanceof RuleTransition) {
            RuleTransition rt = (RuleTransition) p.transition(0);
            addFollowLink(rt.ruleIndex, rt.followState);
        }
    }
}

Example 57 with ATNState

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

the class ParserATNFactory method newState.

public ATNState newState(GrammarAST node) {
    ATNState n = new BasicState();
    n.setRuleIndex(currentRule.index);
    atn.addState(n);
    return n;
}

Example 58 with ATNState

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

the class ParserATNFactory method addEOFTransitionToStartRules.

/**
 * Add an EOF transition to any rule end ATNState that points to nothing
 *  (i.e., for all those rules not invoked by another rule).  These
 *  are start symbols then.
 *
 *  Return the number of grammar entry points; i.e., how many rules are
 *  not invoked by another rule (they can only be invoked from outside).
 *  These are the start rules.
 */
public int addEOFTransitionToStartRules() {
    int n = 0;
    // one unique EOF target for all rules
    ATNState eofTarget = newState(null);
    for (Rule r : g.rules.values()) {
        ATNState stop = atn.ruleToStopState[r.index];
        if (stop.getNumberOfTransitions() > 0)
            continue;
        n++;
        Transition t = new AtomTransition(eofTarget, Token.EOF);
        stop.addTransition(t);
    }
    return n;
}

Example 59 with ATNState

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

the class ParserATNFactory method createATN.

@Override
public ATN createATN() {
    _createATN(g.rules.values());
    assert atn.maxTokenType == g.getMaxTokenType();
    addRuleFollowLinks();
    addEOFTransitionToStartRules();
    ATNOptimizer.optimize(g, atn);
    for (Triple<Rule, ATNState, ATNState> pair : preventEpsilonClosureBlocks) {
        LL1Analyzer analyzer = new LL1Analyzer(atn);
        ATNState blkStart = pair.b;
        ATNState blkStop = pair.c;
        IntervalSet lookahead = analyzer.LOOK(blkStart, blkStop, null);
        if (lookahead.contains(org.antlr.v4.runtime.Token.EPSILON)) {
            ErrorType errorType = pair.a instanceof LeftRecursiveRule ? ErrorType.EPSILON_LR_FOLLOW : ErrorType.EPSILON_CLOSURE;
            g.tool.errMgr.grammarError(errorType, g.fileName, ((GrammarAST) pair.a.ast.getChild(0)).getToken(), pair.a.name);
        }
    }
    optionalCheck: for (Triple<Rule, ATNState, ATNState> pair : preventEpsilonOptionalBlocks) {
        int bypassCount = 0;
        for (int i = 0; i < pair.b.getNumberOfTransitions(); i++) {
            ATNState startState = pair.b.transition(i).target;
            if (startState == pair.c) {
                bypassCount++;
                continue;
            }
            LL1Analyzer analyzer = new LL1Analyzer(atn);
            if (analyzer.LOOK(startState, pair.c, null).contains(org.antlr.v4.runtime.Token.EPSILON)) {
                g.tool.errMgr.grammarError(ErrorType.EPSILON_OPTIONAL, g.fileName, ((GrammarAST) pair.a.ast.getChild(0)).getToken(), pair.a.name);
                continue optionalCheck;
            }
        }
        if (bypassCount != 1) {
            throw new UnsupportedOperationException("Expected optional block with exactly 1 bypass alternative.");
        }
    }
    return atn;
}

Example 60 with ATNState

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

the class ParserATNFactory method set.

/**
 * From set build single edge graph {@code o->o-set->o}.  To conform to
 *  what an alt block looks like, must have extra state on left.
 *  This also handles {@code ~A}, converted to {@code ~{A}} set.
 */
@Override
public Handle set(GrammarAST associatedAST, List<GrammarAST> terminals, boolean invert) {
    ATNState left = newState(associatedAST);
    ATNState right = newState(associatedAST);
    IntervalSet set = new IntervalSet();
    for (GrammarAST t : terminals) {
        int ttype = g.getTokenType(t.getText());
        set.add(ttype);
    }
    if (invert) {
        left.addTransition(new NotSetTransition(right, set));
    } else {
        left.addTransition(new SetTransition(right, set));
    }
    associatedAST.atnState = left;
    return new Handle(left, right);
}