LL1OptionalBlockSingleAlt.java 文件源码

public LL1OptionalBlockSingleAlt(OutputModelFactory factory,
                                     GrammarAST blkAST,
                                     List<CodeBlockForAlt> alts)
    {
        super(factory, blkAST, alts);
        this.decision = ((DecisionState)blkAST.atnState).decision;

        /** Lookahead for each alt 1..n */
//      IntervalSet[] altLookSets = LinearApproximator.getLL1LookaheadSets(dfa);
        IntervalSet[] altLookSets = factory.getGrammar().decisionLOOK.get(decision);
        altLook = getAltLookaheadAsStringLists(altLookSets);
        IntervalSet look = altLookSets[0];
        IntervalSet followLook = altLookSets[1];

        IntervalSet expecting = look.or(followLook);
        this.error = getThrowNoViableAlt(factory, blkAST, expecting);

        expr = addCodeForLookaheadTempVar(look);
        followExpr = factory.getLL1Test(followLook, blkAST);
    }