Examples with org.antlr.v4.runtime.tree org.antlr.v4.runtime.tree used on opensource projects

Example 16 with org.antlr.v4.runtime.tree

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

the class ParserATNFactory method createATN.

@NotNull
@Override
public ATN createATN() {
    _createATN(g.rules.values());
    assert atn.maxTokenType == g.getMaxTokenType();
    addRuleFollowLinks();
    addEOFTransitionToStartRules();
    ATNOptimizer.optimize(g, atn);
    for (Tuple3<? extends Rule, ? extends ATNState, ? extends ATNState> pair : preventEpsilonClosureBlocks) {
        LL1Analyzer analyzer = new LL1Analyzer(atn);
        ATNState blkStart = pair.getItem2();
        ATNState blkStop = pair.getItem3();
        IntervalSet lookahead = analyzer.LOOK(blkStart, blkStop, PredictionContext.EMPTY_LOCAL);
        if (lookahead.contains(org.antlr.v4.runtime.Token.EPSILON)) {
            ErrorType errorType = pair.getItem1() instanceof LeftRecursiveRule ? ErrorType.EPSILON_LR_FOLLOW : ErrorType.EPSILON_CLOSURE;
            g.tool.errMgr.grammarError(errorType, g.fileName, ((GrammarAST) pair.getItem1().ast.getChild(0)).getToken(), pair.getItem1().name);
        }
    }
    optionalCheck: for (Tuple3<? extends Rule, ? extends ATNState, ? extends ATNState> pair : preventEpsilonOptionalBlocks) {
        int bypassCount = 0;
        for (int i = 0; i < pair.getItem2().getNumberOfTransitions(); i++) {
            ATNState startState = pair.getItem2().transition(i).target;
            if (startState == pair.getItem3()) {
                bypassCount++;
                continue;
            }
            LL1Analyzer analyzer = new LL1Analyzer(atn);
            if (analyzer.LOOK(startState, pair.getItem3(), PredictionContext.EMPTY_LOCAL).contains(org.antlr.v4.runtime.Token.EPSILON)) {
                g.tool.errMgr.grammarError(ErrorType.EPSILON_OPTIONAL, g.fileName, ((GrammarAST) pair.getItem1().ast.getChild(0)).getToken(), pair.getItem1().name);
                continue optionalCheck;
            }
        }
        if (bypassCount != 1) {
            throw new UnsupportedOperationException("Expected optional block with exactly 1 bypass alternative.");
        }
    }
    return atn;
}