java类org.antlr.v4.runtime.atn.DecisionState的实例源码

protected String getStateLabel(ATNState s) {
    if ( s==null ) return "null";
    String stateLabel = "";

    if (s instanceof BlockStartState) {
        stateLabel += "→\\n";
    }
    else if (s instanceof BlockEndState) {
        stateLabel += "←\\n";
    }

    stateLabel += String.valueOf(s.stateNumber);

    if (s instanceof PlusBlockStartState || s instanceof PlusLoopbackState) {
        stateLabel += "+";
    }
    else if (s instanceof StarBlockStartState || s instanceof StarLoopEntryState || s instanceof StarLoopbackState) {
        stateLabel += "*";
    }

    if ( s instanceof DecisionState && ((DecisionState)s).decision>=0 ) {
        stateLabel = stateLabel+"\\nd="+((DecisionState)s).decision;
    }

    return stateLabel;
}

/** identify the ATN states where we need to set the outer alt number.
 *  For regular rules, that's the block at the target to rule start state.
 *  For left-recursive rules, we track the primary block, which looks just
 *  like a regular rule's outer block, and the star loop block (always
 *  there even if 1 alt).
 */
public BitSet findOuterMostDecisionStates() {
    BitSet track = new BitSet(atn.states.size());
    int numberOfDecisions = atn.getNumberOfDecisions();
    for (int i = 0; i < numberOfDecisions; i++) {
        DecisionState decisionState = atn.getDecisionState(i);
        RuleStartState startState = atn.ruleToStartState[decisionState.ruleIndex];
        // Look for StarLoopEntryState that is in any left recursive rule
        if ( decisionState instanceof StarLoopEntryState) {
            StarLoopEntryState loopEntry = (StarLoopEntryState)decisionState;
            if ( loopEntry.isPrecedenceDecision ) {
                // Recursive alts always result in a (...)* in the transformed
                // left recursive rule and that always has a BasicBlockStartState
                // even if just 1 recursive alt exists.
                ATNState blockStart = loopEntry.transition(0).target;
                // track the StarBlockStartState associated with the recursive alternatives
                track.set(blockStart.stateNumber);
            }
        }
        else if ( startState.transition(0).target == decisionState ) {
            // always track outermost block for any rule if it exists
            track.set(decisionState.stateNumber);
        }
    }
    return track;
}

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);
    }

@Override
public Choice getChoiceBlock(BlockAST blkAST, List<CodeBlockForAlt> alts, GrammarAST labelAST) {
    int decision = ((DecisionState)blkAST.atnState).decision;
    Choice c;
    if ( !g.tool.force_atn && AnalysisPipeline.disjoint(g.decisionLOOK.get(decision)) ) {
        c = getLL1ChoiceBlock(blkAST, alts);
    }
    else {
        c = getComplexChoiceBlock(blkAST, alts);
    }

    if ( labelAST!=null ) { // for x=(...), define x or x_list
        String label = labelAST.getText();
        Decl d = getTokenLabelDecl(label);
        c.label = d;
        getCurrentRuleFunction().addContextDecl(labelAST.getAltLabel(), d);
        if ( labelAST.parent.getType() == ANTLRParser.PLUS_ASSIGN  ) {
            String listLabel = gen.getTarget().getListLabel(label);
            TokenListDecl l = new TokenListDecl(this, listLabel);
            getCurrentRuleFunction().addContextDecl(labelAST.getAltLabel(), l);
        }
    }

    return c;
}

@Override
public Choice getEBNFBlock(GrammarAST ebnfRoot, List<CodeBlockForAlt> alts) {
    if (!g.tool.force_atn) {
        int decision;
        if ( ebnfRoot.getType()==ANTLRParser.POSITIVE_CLOSURE ) {
            decision = ((PlusLoopbackState)ebnfRoot.atnState).decision;
        }
        else if ( ebnfRoot.getType()==ANTLRParser.CLOSURE ) {
            decision = ((StarLoopEntryState)ebnfRoot.atnState).decision;
        }
        else {
            decision = ((DecisionState)ebnfRoot.atnState).decision;
        }

        if ( AnalysisPipeline.disjoint(g.decisionLOOK.get(decision)) ) {
            return getLL1EBNFBlock(ebnfRoot, alts);
        }
    }

    return getComplexEBNFBlock(ebnfRoot, alts);
}

/** Override this method so that we can record which alternative
     *  was taken at each decision point. For non-left recursive rules,
     *  it's simple. Set decisionStatesThatSetOuterAltNumInContext
     *  indicates which decision states should set the outer alternative number.
     *
     *  <p>Left recursive rules are much more complicated to deal with:
     *  there is typically a decision for the primary alternatives and a
     *  decision to choose between the recursive operator alternatives.
     *  For example, the following left recursive rule has two primary and 2
     *  recursive alternatives.</p>
     *
         e : e '*' e
           | '-' INT
           | e '+' e
           | ID
           ;

     *  <p>ANTLR rewrites that rule to be</p>

         e[int precedence]
             : ('-' INT | ID)
             ( {...}? '*' e[5]
             | {...}? '+' e[3]
             )*
            ;

     *
     *  <p>So, there are two decisions associated with picking the outermost alt.
     *  This complicates our tracking significantly. The outermost alternative number
     *  is a function of the decision (ATN state) within a left recursive rule and the
     *  predicted alternative coming back from adaptivePredict().
     *
     *  We use stateToAltsMap as a cache to avoid expensive calls to
     *  getRecursiveOpAlts().
     */
    @Override
    protected int visitDecisionState(DecisionState p) {
        int predictedAlt = super.visitDecisionState(p);
        if( p.getNumberOfTransitions() > 1) {
//          System.out.println("decision "+p.decision+": "+predictedAlt);
            if( p.decision == this.overrideDecision &&
                this._input.index() == this.overrideDecisionInputIndex )
            {
                overrideDecisionRoot = (GrammarInterpreterRuleContext)getContext();
            }
        }

        GrammarInterpreterRuleContext ctx = (GrammarInterpreterRuleContext)_ctx;
        if ( decisionStatesThatSetOuterAltNumInContext.get(p.stateNumber) ) {
            ctx.outerAltNum = predictedAlt;
            Rule r = g.getRule(p.ruleIndex);
            if ( atn.ruleToStartState[r.index].isLeftRecursiveRule ) {
                int[] alts = stateToAltsMap[p.stateNumber];
                LeftRecursiveRule lr = (LeftRecursiveRule) g.getRule(p.ruleIndex);
                if (p.getStateType() == ATNState.BLOCK_START) {
                    if ( alts==null ) {
                        alts = lr.getPrimaryAlts();
                        stateToAltsMap[p.stateNumber] = alts; // cache it
                    }
                }
                else if ( p.getStateType() == ATNState.STAR_BLOCK_START ) {
                    if ( alts==null ) {
                        alts = lr.getRecursiveOpAlts();
                        stateToAltsMap[p.stateNumber] = alts; // cache it
                    }
                }
                ctx.outerAltNum = alts[predictedAlt];
            }
        }

        return predictedAlt;
    }

public LL1AltBlock(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 = factory.getGrammar().decisionLOOK.get(decision);
    altLook = getAltLookaheadAsStringLists(altLookSets);

    IntervalSet expecting = IntervalSet.or(altLookSets); // combine alt sets
    this.error = getThrowNoViableAlt(factory, blkAST, expecting);
}

public static int getQidDecision(@NonNull ATN atn) {
    ATNState decisionState = atn.ruleToStartState[GoParser.RULE_qualifiedIdentifier].transition(0).target;
    if (decisionState instanceof DecisionState) {
        return ((DecisionState)decisionState).decision;
    } else {
        return -1;
    }
}

@Override
    protected int visitDecisionState(DecisionState p) {
        int predictedAlt = super.visitDecisionState(p);
        if ( p.getNumberOfTransitions()>1 ) {
//          System.out.println("decision "+p.decision+": "+predictedAlt);
            if ( p.decision==this.overrideDecision &&
            this._input.index()==this.overrideDecisionInputIndex ) {
                ((PreviewInterpreterRuleContext)overrideDecisionRoot).isDecisionOverrideRoot = true;
            }
        }
        return predictedAlt;
    }

/** Return a list of parse trees, one for each alternative in a decision
 *  given the same input.
 *
 *  Very similar to {@link #getAllPossibleParseTrees} except
 *  that it re-parses the input for every alternative in a decision,
 *  not just the ambiguous ones (there is no alts parameter here).
 *  This method also tries to reduce the size of the parse trees
 *  by stripping away children of the tree that are completely out of range
 *  of startIndex..stopIndex. Also, because errors are expected, we
 *  use a specialized error handler that more or less bails out
 *  but that also consumes the first erroneous token at least. This
 *  ensures that an error node will be in the parse tree for display.
 *
 *  NOTES:
   // we must parse the entire input now with decision overrides
// we cannot parse a subset because it could be that a decision
// above our decision of interest needs to read way past
// lookaheadInfo.stopIndex. It seems like there is no escaping
// the use of a full and complete token stream if we are
// resetting to token index 0 and re-parsing from the start symbol.
// It's not easy to restart parsing somewhere in the middle like a
// continuation because our call stack does not match the
// tree stack because of left recursive rule rewriting. grrrr!
 *
 * @since 4.5.1
 */
public static List<ParserRuleContext> getLookaheadParseTrees(Grammar g,
                                                             ParserInterpreter originalParser,
                                                             TokenStream tokens,
                                                             int startRuleIndex,
                                                             int decision,
                                                             int startIndex,
                                                             int stopIndex)
{
    List<ParserRuleContext> trees = new ArrayList<ParserRuleContext>();
    // Create a new parser interpreter to parse the ambiguous subphrase
    ParserInterpreter parser = deriveTempParserInterpreter(g, originalParser, tokens);
    BailButConsumeErrorStrategy errorHandler = new BailButConsumeErrorStrategy();
    parser.setErrorHandler(errorHandler);

    DecisionState decisionState = originalParser.getATN().decisionToState.get(decision);

    for (int alt=1; alt<=decisionState.getTransitions().length; alt++) {
        // re-parse entire input for all ambiguous alternatives
        // (don't have to do first as it's been parsed, but do again for simplicity
        //  using this temp parser.)
        parser.reset();
        parser.addDecisionOverride(decision, startIndex, alt);
        ParserRuleContext tt = parser.parse(startRuleIndex);
        int stopTreeAt = stopIndex;
        if ( errorHandler.firstErrorTokenIndex>=0 ) {
            stopTreeAt = errorHandler.firstErrorTokenIndex; // cut off rest at first error
        }
        ParserRuleContext subtree =
            Trees.getRootOfSubtreeEnclosingRegion(tt,
                                                  startIndex,
                                                  stopTreeAt);
        // Use higher of overridden decision tree or tree enclosing all tokens
        if ( Trees.isAncestorOf(parser.getOverrideDecisionRoot(), subtree) ) {
            subtree = parser.getOverrideDecisionRoot();
        }
        Trees.stripChildrenOutOfRange(subtree, parser.getOverrideDecisionRoot(), startIndex, stopTreeAt);
        trees.add(subtree);
    }

    return trees;
}

public DFA(@NotNull DecisionState atnStartState) {
    this(atnStartState, 0);
}

public DFA(@NotNull DecisionState atnStartState, int decision) {
    this.atnStartState = atnStartState;
    this.decision = decision;
}

public void selectDecisionInGrammar(PreviewState previewState, int decision) {
        final ANTLRv4PluginController controller = ANTLRv4PluginController.getInstance(previewState.project);
        if ( controller==null ) return;
        final Editor grammarEditor = controller.getEditor(previewState.grammarFile);
        if ( grammarEditor==null ) return;

        DecisionState decisionState = previewState.g.atn.getDecisionState(decision);
        Interval region = previewState.g.getStateToGrammarRegion(decisionState.stateNumber);
        if ( region==null ) {
            System.err.println("decision "+decision+" has state "+decisionState.stateNumber+" but no region");
            return;
        }

        InputPanel.removeHighlighters(grammarEditor, ProfilerPanel.DECISION_INFO_KEY);

        org.antlr.runtime.TokenStream tokens = previewState.g.tokenStream;
        if ( region.a>=tokens.size() || region.b>=tokens.size() ) {
//          System.out.println("out of range: " + region + " tokens.size()=" + tokens.size());
            return;
        }
        CommonToken startToken = (CommonToken) tokens.get(region.a);
        CommonToken stopToken = (CommonToken) tokens.get(region.b);
        JBColor effectColor = JBColor.darkGray;
        DecisionInfo decisionInfo = previewState.parsingResult.parser.getParseInfo().getDecisionInfo()[decision];
        if ( decisionInfo.predicateEvals.size()>0 ) {
            effectColor = new JBColor(PREDEVAL_COLOR, AMBIGUITY_COLOR);
        }
        if ( decisionInfo.contextSensitivities.size()>0 ) {
            effectColor = new JBColor(FULLCTX_COLOR, AMBIGUITY_COLOR);
        }
        if ( decisionInfo.ambiguities.size()>0 ) {
            effectColor = new JBColor(AMBIGUITY_COLOR, AMBIGUITY_COLOR);
        }

        TextAttributes attr =
            new TextAttributes(JBColor.BLACK, JBColor.WHITE, effectColor,
                               EffectType.ROUNDED_BOX, Font.PLAIN);
        MarkupModel markupModel = grammarEditor.getMarkupModel();
        final RangeHighlighter rangeHighlighter = markupModel.addRangeHighlighter(
            startToken.getStartIndex(),
            stopToken.getStopIndex()+1,
            HighlighterLayer.SELECTION, // layer
            attr,
            HighlighterTargetArea.EXACT_RANGE
                                                                                 );
        rangeHighlighter.putUserData(DECISION_INFO_KEY, decisionInfo);

//      System.out.println("dec " + decision + " from " + startToken + " to " + stopToken);

        ScrollingModel scrollingModel = grammarEditor.getScrollingModel();
        CaretModel caretModel = grammarEditor.getCaretModel();
        caretModel.moveToOffset(startToken.getStartIndex());
        scrollingModel.scrollToCaret(ScrollType.MAKE_VISIBLE);
    }