Examples with Alternatives org.eclipse.xtext.Alternatives used on opensource projects

Example 11 with Alternatives

use of org.eclipse.xtext.Alternatives in project xtext-core by eclipse.

the class XtextSemanticSequencer method sequence.

@Override
public void sequence(ISerializationContext context, EObject semanticObject) {
    EPackage epackage = semanticObject.eClass().getEPackage();
    ParserRule rule = context.getParserRule();
    Action action = context.getAssignedAction();
    Set<Parameter> parameters = context.getEnabledBooleanParameters();
    if (epackage == XtextPackage.eINSTANCE)
        switch(semanticObject.eClass().getClassifierID()) {
            case XtextPackage.ACTION:
                if (rule == grammarAccess.getAlternativesRule() || action == grammarAccess.getAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getConditionalBranchRule() || rule == grammarAccess.getUnorderedGroupRule() || action == grammarAccess.getUnorderedGroupAccess().getUnorderedGroupElementsAction_1_0() || rule == grammarAccess.getGroupRule() || action == grammarAccess.getGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getAbstractTokenRule() || rule == grammarAccess.getAbstractTokenWithCardinalityRule() || rule == grammarAccess.getAbstractTerminalRule() || rule == grammarAccess.getParenthesizedElementRule()) {
                    sequence_AbstractTokenWithCardinality_Action(context, (Action) semanticObject);
                    return;
                } else if (rule == grammarAccess.getActionRule()) {
                    sequence_Action(context, (Action) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.ALTERNATIVES:
                if (rule == grammarAccess.getAlternativesRule() || action == grammarAccess.getAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getConditionalBranchRule() || rule == grammarAccess.getUnorderedGroupRule() || action == grammarAccess.getUnorderedGroupAccess().getUnorderedGroupElementsAction_1_0() || rule == grammarAccess.getGroupRule() || action == grammarAccess.getGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getAbstractTokenRule() || rule == grammarAccess.getAbstractTokenWithCardinalityRule() || rule == grammarAccess.getAbstractTerminalRule() || rule == grammarAccess.getParenthesizedElementRule()) {
                    sequence_AbstractTokenWithCardinality_Alternatives(context, (Alternatives) semanticObject);
                    return;
                } else if (rule == grammarAccess.getAssignableTerminalRule() || rule == grammarAccess.getParenthesizedAssignableElementRule() || rule == grammarAccess.getAssignableAlternativesRule() || action == grammarAccess.getAssignableAlternativesAccess().getAlternativesElementsAction_1_0()) {
                    sequence_AssignableAlternatives(context, (Alternatives) semanticObject);
                    return;
                } else if (rule == grammarAccess.getEnumLiteralsRule()) {
                    sequence_EnumLiterals(context, (Alternatives) semanticObject);
                    return;
                } else if (rule == grammarAccess.getTerminalAlternativesRule() || action == grammarAccess.getTerminalAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getTerminalGroupRule() || action == grammarAccess.getTerminalGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getTerminalTokenRule() || rule == grammarAccess.getTerminalTokenElementRule() || rule == grammarAccess.getParenthesizedTerminalElementRule()) {
                    sequence_TerminalAlternatives_TerminalToken(context, (Alternatives) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.ANNOTATION:
                sequence_Annotation(context, (Annotation) semanticObject);
                return;
            case XtextPackage.ASSIGNMENT:
                if (rule == grammarAccess.getAlternativesRule() || action == grammarAccess.getAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getConditionalBranchRule() || rule == grammarAccess.getUnorderedGroupRule() || action == grammarAccess.getUnorderedGroupAccess().getUnorderedGroupElementsAction_1_0() || rule == grammarAccess.getGroupRule() || action == grammarAccess.getGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getAbstractTokenRule() || rule == grammarAccess.getAbstractTokenWithCardinalityRule() || rule == grammarAccess.getAbstractTerminalRule() || rule == grammarAccess.getParenthesizedElementRule()) {
                    sequence_AbstractTokenWithCardinality_Assignment(context, (Assignment) semanticObject);
                    return;
                } else if (rule == grammarAccess.getAssignmentRule()) {
                    sequence_Assignment(context, (Assignment) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.CHARACTER_RANGE:
                if (rule == grammarAccess.getCharacterRangeRule()) {
                    sequence_CharacterRange(context, (CharacterRange) semanticObject);
                    return;
                } else if (rule == grammarAccess.getTerminalAlternativesRule() || action == grammarAccess.getTerminalAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getTerminalGroupRule() || action == grammarAccess.getTerminalGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getTerminalTokenRule() || rule == grammarAccess.getTerminalTokenElementRule() || rule == grammarAccess.getParenthesizedTerminalElementRule()) {
                    sequence_CharacterRange_TerminalToken(context, (CharacterRange) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.CONJUNCTION:
                sequence_Conjunction(context, (Conjunction) semanticObject);
                return;
            case XtextPackage.CROSS_REFERENCE:
                sequence_CrossReference(context, (CrossReference) semanticObject);
                return;
            case XtextPackage.DISJUNCTION:
                sequence_Disjunction(context, (Disjunction) semanticObject);
                return;
            case XtextPackage.EOF:
                if (rule == grammarAccess.getEOFRule()) {
                    sequence_EOF(context, (EOF) semanticObject);
                    return;
                } else if (rule == grammarAccess.getTerminalAlternativesRule() || action == grammarAccess.getTerminalAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getTerminalGroupRule() || action == grammarAccess.getTerminalGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getTerminalTokenRule() || rule == grammarAccess.getTerminalTokenElementRule() || rule == grammarAccess.getParenthesizedTerminalElementRule()) {
                    sequence_EOF_TerminalToken(context, (EOF) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.ENUM_LITERAL_DECLARATION:
                sequence_EnumLiteralDeclaration(context, (EnumLiteralDeclaration) semanticObject);
                return;
            case XtextPackage.ENUM_RULE:
                sequence_EnumRule(context, (EnumRule) semanticObject);
                return;
            case XtextPackage.GENERATED_METAMODEL:
                sequence_GeneratedMetamodel(context, (GeneratedMetamodel) semanticObject);
                return;
            case XtextPackage.GRAMMAR:
                sequence_Grammar(context, (Grammar) semanticObject);
                return;
            case XtextPackage.GROUP:
                if (rule == grammarAccess.getAlternativesRule() || action == grammarAccess.getAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getConditionalBranchRule() || rule == grammarAccess.getUnorderedGroupRule() || action == grammarAccess.getUnorderedGroupAccess().getUnorderedGroupElementsAction_1_0() || rule == grammarAccess.getGroupRule() || action == grammarAccess.getGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getAbstractTokenRule() || rule == grammarAccess.getAbstractTokenWithCardinalityRule() || rule == grammarAccess.getAbstractTerminalRule() || rule == grammarAccess.getParenthesizedElementRule()) {
                    sequence_AbstractTokenWithCardinality_ConditionalBranch_Group_PredicatedGroup(context, (Group) semanticObject);
                    return;
                } else if (rule == grammarAccess.getPredicatedGroupRule()) {
                    sequence_PredicatedGroup(context, (Group) semanticObject);
                    return;
                } else if (rule == grammarAccess.getTerminalAlternativesRule() || action == grammarAccess.getTerminalAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getTerminalGroupRule() || action == grammarAccess.getTerminalGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getTerminalTokenRule() || rule == grammarAccess.getTerminalTokenElementRule() || rule == grammarAccess.getParenthesizedTerminalElementRule()) {
                    sequence_TerminalGroup_TerminalToken(context, (Group) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.KEYWORD:
                if (rule == grammarAccess.getAlternativesRule() || action == grammarAccess.getAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getConditionalBranchRule() || rule == grammarAccess.getUnorderedGroupRule() || action == grammarAccess.getUnorderedGroupAccess().getUnorderedGroupElementsAction_1_0() || rule == grammarAccess.getGroupRule() || action == grammarAccess.getGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getAbstractTokenRule() || rule == grammarAccess.getAbstractTokenWithCardinalityRule() || rule == grammarAccess.getAbstractTerminalRule() || rule == grammarAccess.getParenthesizedElementRule()) {
                    sequence_AbstractTokenWithCardinality_Keyword_PredicatedKeyword(context, (Keyword) semanticObject);
                    return;
                } else if (rule == grammarAccess.getKeywordRule() || rule == grammarAccess.getAssignableTerminalRule() || rule == grammarAccess.getParenthesizedAssignableElementRule() || rule == grammarAccess.getAssignableAlternativesRule() || action == grammarAccess.getAssignableAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getCrossReferenceableTerminalRule() || rule == grammarAccess.getCharacterRangeRule() || action == grammarAccess.getCharacterRangeAccess().getCharacterRangeLeftAction_1_0()) {
                    sequence_Keyword(context, (Keyword) semanticObject);
                    return;
                } else if (rule == grammarAccess.getTerminalAlternativesRule() || action == grammarAccess.getTerminalAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getTerminalGroupRule() || action == grammarAccess.getTerminalGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getTerminalTokenRule() || rule == grammarAccess.getTerminalTokenElementRule() || rule == grammarAccess.getParenthesizedTerminalElementRule()) {
                    sequence_Keyword_TerminalToken(context, (Keyword) semanticObject);
                    return;
                } else if (rule == grammarAccess.getPredicatedKeywordRule()) {
                    sequence_PredicatedKeyword(context, (Keyword) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.LITERAL_CONDITION:
                sequence_LiteralCondition(context, (LiteralCondition) semanticObject);
                return;
            case XtextPackage.NAMED_ARGUMENT:
                sequence_NamedArgument(context, (NamedArgument) semanticObject);
                return;
            case XtextPackage.NEGATED_TOKEN:
                if (rule == grammarAccess.getAbstractNegatedTokenRule() || rule == grammarAccess.getNegatedTokenRule()) {
                    sequence_NegatedToken(context, (NegatedToken) semanticObject);
                    return;
                } else if (rule == grammarAccess.getTerminalAlternativesRule() || action == grammarAccess.getTerminalAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getTerminalGroupRule() || action == grammarAccess.getTerminalGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getTerminalTokenRule() || rule == grammarAccess.getTerminalTokenElementRule() || rule == grammarAccess.getParenthesizedTerminalElementRule()) {
                    sequence_NegatedToken_TerminalToken(context, (NegatedToken) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.NEGATION:
                sequence_Negation(context, (Negation) semanticObject);
                return;
            case XtextPackage.PARAMETER:
                sequence_Parameter(context, (Parameter) semanticObject);
                return;
            case XtextPackage.PARAMETER_REFERENCE:
                sequence_ParameterReference(context, (ParameterReference) semanticObject);
                return;
            case XtextPackage.PARSER_RULE:
                sequence_ParserRule_RuleNameAndParams(context, (ParserRule) semanticObject);
                return;
            case XtextPackage.REFERENCED_METAMODEL:
                sequence_ReferencedMetamodel(context, (ReferencedMetamodel) semanticObject);
                return;
            case XtextPackage.RULE_CALL:
                if (rule == grammarAccess.getAlternativesRule() || action == grammarAccess.getAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getConditionalBranchRule() || rule == grammarAccess.getUnorderedGroupRule() || action == grammarAccess.getUnorderedGroupAccess().getUnorderedGroupElementsAction_1_0() || rule == grammarAccess.getGroupRule() || action == grammarAccess.getGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getAbstractTokenRule() || rule == grammarAccess.getAbstractTokenWithCardinalityRule() || rule == grammarAccess.getAbstractTerminalRule() || rule == grammarAccess.getParenthesizedElementRule()) {
                    sequence_AbstractTokenWithCardinality_PredicatedRuleCall_RuleCall(context, (RuleCall) semanticObject);
                    return;
                } else if (rule == grammarAccess.getPredicatedRuleCallRule()) {
                    sequence_PredicatedRuleCall(context, (RuleCall) semanticObject);
                    return;
                } else if (rule == grammarAccess.getRuleCallRule() || rule == grammarAccess.getAssignableTerminalRule() || rule == grammarAccess.getParenthesizedAssignableElementRule() || rule == grammarAccess.getAssignableAlternativesRule() || action == grammarAccess.getAssignableAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getCrossReferenceableTerminalRule()) {
                    sequence_RuleCall(context, (RuleCall) semanticObject);
                    return;
                } else if (rule == grammarAccess.getTerminalRuleCallRule()) {
                    sequence_TerminalRuleCall(context, (RuleCall) semanticObject);
                    return;
                } else if (rule == grammarAccess.getTerminalAlternativesRule() || action == grammarAccess.getTerminalAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getTerminalGroupRule() || action == grammarAccess.getTerminalGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getTerminalTokenRule() || rule == grammarAccess.getTerminalTokenElementRule() || rule == grammarAccess.getParenthesizedTerminalElementRule()) {
                    sequence_TerminalRuleCall_TerminalToken(context, (RuleCall) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.TERMINAL_RULE:
                sequence_TerminalRule(context, (TerminalRule) semanticObject);
                return;
            case XtextPackage.TYPE_REF:
                sequence_TypeRef(context, (TypeRef) semanticObject);
                return;
            case XtextPackage.UNORDERED_GROUP:
                sequence_AbstractTokenWithCardinality_UnorderedGroup(context, (UnorderedGroup) semanticObject);
                return;
            case XtextPackage.UNTIL_TOKEN:
                if (rule == grammarAccess.getTerminalAlternativesRule() || action == grammarAccess.getTerminalAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getTerminalGroupRule() || action == grammarAccess.getTerminalGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getTerminalTokenRule() || rule == grammarAccess.getTerminalTokenElementRule() || rule == grammarAccess.getParenthesizedTerminalElementRule()) {
                    sequence_TerminalToken_UntilToken(context, (UntilToken) semanticObject);
                    return;
                } else if (rule == grammarAccess.getAbstractNegatedTokenRule() || rule == grammarAccess.getUntilTokenRule()) {
                    sequence_UntilToken(context, (UntilToken) semanticObject);
                    return;
                } else
                    break;
            case XtextPackage.WILDCARD:
                if (rule == grammarAccess.getTerminalAlternativesRule() || action == grammarAccess.getTerminalAlternativesAccess().getAlternativesElementsAction_1_0() || rule == grammarAccess.getTerminalGroupRule() || action == grammarAccess.getTerminalGroupAccess().getGroupElementsAction_1_0() || rule == grammarAccess.getTerminalTokenRule() || rule == grammarAccess.getTerminalTokenElementRule() || rule == grammarAccess.getParenthesizedTerminalElementRule()) {
                    sequence_TerminalToken_Wildcard(context, (Wildcard) semanticObject);
                    return;
                } else if (rule == grammarAccess.getWildcardRule()) {
                    sequence_Wildcard(context, (Wildcard) semanticObject);
                    return;
                } else
                    break;
        }
    if (errorAcceptor != null)
        errorAcceptor.accept(diagnosticProvider.createInvalidContextOrTypeDiagnostic(semanticObject, context));
}

Example 12 with Alternatives

use of org.eclipse.xtext.Alternatives in project xtext-core by eclipse.

the class KeywordBasedValueConverter method setRule.

/**
 * @throws IllegalArgumentException if the rule is not a datatype rule or does not fulfill
 *   the pattern <pre>RuleName: 'keyword' | 'other';</pre>
 */
@Override
public void setRule(AbstractRule rule) {
    this.rule = rule;
    if (!GrammarUtil.isDatatypeRule(rule))
        throw new IllegalArgumentException(rule.getName() + " is not a data type rule");
    if (!(rule.getAlternatives() instanceof Alternatives) && !(rule.getAlternatives() instanceof Keyword)) {
        throw new IllegalArgumentException(rule.getName() + " is not a simple keyword nor an alternative");
    }
    if (rule.getAlternatives() instanceof Keyword) {
        keywords = ImmutableSet.of(keywordToString((Keyword) rule.getAlternatives()));
    } else {
        Alternatives alternatives = (Alternatives) rule.getAlternatives();
        ImmutableSet.Builder<String> builder = ImmutableSet.builder();
        for (AbstractElement element : alternatives.getElements()) {
            if (!(element instanceof Keyword)) {
                throw new IllegalArgumentException(rule.getName() + "'s body does not contain an alternative of keywords");
            }
            builder.add(keywordToString((Keyword) element));
        }
        keywords = builder.build();
    }
}

Example 13 with Alternatives

use of org.eclipse.xtext.Alternatives in project xtext-core by eclipse.

the class ConcreteSyntaxConstraintProvider method createSummarizedAssignments.

protected List<ISyntaxConstraint> createSummarizedAssignments(CompoundElement group, List<AbstractElement> candidates, EClass semanticType, boolean optional) {
    Multimap<String, Assignment> feature2ass = HashMultimap.create();
    Multimap<String, AbstractElement> feature2child = HashMultimap.create();
    for (AbstractElement c : candidates) {
        TreeIterator<EObject> i = EcoreUtil2.eAll(c);
        while (i.hasNext()) {
            EObject obj = i.next();
            if (obj instanceof RuleCall || obj instanceof Action || obj instanceof Alternatives)
                return Lists.newArrayList();
            else if (obj instanceof Group) {
                Set<String> names = Sets.newHashSet();
                for (Assignment ass : EcoreUtil2.getAllContentsOfType(obj, Assignment.class)) names.add(ass.getFeature());
                if (names.size() > 1)
                    i.prune();
            } else if (obj instanceof Assignment) {
                Assignment a = (Assignment) obj;
                feature2ass.put(a.getFeature(), a);
                feature2child.put(a.getFeature(), c);
                i.prune();
            }
        }
    }
    List<ISyntaxConstraint> result = Lists.newArrayList();
    for (Map.Entry<String, Collection<Assignment>> ent : feature2ass.asMap().entrySet()) {
        if (ent.getValue().size() < 2 || feature2child.get(ent.getKey()).size() < 2)
            continue;
        int required = 0, multiplies = 0;
        for (Assignment assignment : ent.getValue()) {
            AbstractElement e = assignment;
            while (e != group) if (isMultipleCardinality(e)) {
                multiplies++;
                break;
            } else
                e = (AbstractElement) e.eContainer();
            e = assignment;
            while (e != group) if (isOptionalCardinality(e))
                break;
            else
                e = (AbstractElement) e.eContainer();
            if (e == group)
                required++;
        }
        if (required > 1 || multiplies < 1)
            continue;
        candidates.removeAll(feature2child.get(ent.getKey()));
        optional = optional || required < 1;
        result.add(createElement(ConstraintType.ASSIGNMENT, ent.getValue().iterator().next(), semanticType, true, optional));
    }
    return result;
}

Example 14 with Alternatives

use of org.eclipse.xtext.Alternatives in project xtext-core by eclipse.

the class XtextValidator method checkCurrentMustBeUnassigned.

private void checkCurrentMustBeUnassigned(final AbstractElement element) {
    final ParserRule rule = GrammarUtil.containingParserRule(element);
    if (GrammarUtil.isDatatypeRule(rule))
        return;
    XtextSwitch<Boolean> visitor = new XtextSwitch<Boolean>() {

        private boolean isNull = !rule.isFragment();

        @Override
        public Boolean caseAbstractElement(AbstractElement object) {
            return isNull;
        }

        @Override
        public Boolean caseAlternatives(Alternatives object) {
            final boolean wasIsNull = isNull;
            boolean localIsNull = wasIsNull;
            for (AbstractElement element : object.getElements()) {
                isNull = wasIsNull;
                localIsNull &= doSwitch(element);
            }
            isNull = localIsNull;
            return isNull;
        }

        @Override
        public Boolean caseUnorderedGroup(UnorderedGroup object) {
            final boolean wasIsNull = isNull;
            boolean localIsNull = wasIsNull;
            for (AbstractElement element : object.getElements()) {
                isNull = wasIsNull;
                localIsNull |= doSwitch(element);
            }
            isNull = localIsNull;
            return isNull;
        }

        @Override
        public Boolean caseAssignment(Assignment object) {
            isNull = false;
            return isNull;
        }

        @Override
        public Boolean caseGroup(Group object) {
            for (AbstractElement element : object.getElements()) doSwitch(element);
            return isNull;
        }

        @Override
        public Boolean caseAction(Action object) {
            if (object == element) {
                if (!(isNull && !isMany(object))) {
                    error("An unassigned action is not allowed, when the 'current' was already created.", object, null);
                    checkDone();
                }
            }
            isNull = false;
            return isNull;
        }

        @Override
        public Boolean caseRuleCall(RuleCall object) {
            if (object == element) {
                AbstractRule calledRule = object.getRule();
                if (calledRule instanceof ParserRule && ((ParserRule) calledRule).isFragment()) {
                    isNull = false;
                    return isNull;
                }
                if (!(isNull && !isMany(object))) {
                    error("An unassigned rule call is not allowed, when the 'current' was already created.", object, null);
                    checkDone();
                }
            }
            return doSwitch(object.getRule());
        }

        @Override
        public Boolean caseParserRule(ParserRule object) {
            isNull = GrammarUtil.isDatatypeRule(object);
            return isNull;
        }

        @Override
        public Boolean caseTerminalRule(TerminalRule object) {
            isNull = true;
            return isNull;
        }

        public boolean isMany(AbstractElement element) {
            return GrammarUtil.isMultipleCardinality(element) || ((element.eContainer() instanceof AbstractElement) && isMany((AbstractElement) element.eContainer()));
        }
    };
    visitor.doSwitch(rule.getAlternatives());
}

Example 15 with Alternatives

use of org.eclipse.xtext.Alternatives in project xtext-core by eclipse.

the class XtextValidator method checkAssignedActionAfterAssignment.

@Check
public void checkAssignedActionAfterAssignment(final Action action) {
    if (action.getFeature() != null) {
        ParserRule rule = GrammarUtil.containingParserRule(action);
        if (rule.isFragment() && !rule.isWildcard()) {
            error("An action is not allowed in fragments.", action, null);
            return;
        }
        XtextSwitch<Boolean> visitor = new XtextSwitch<Boolean>() {

            private boolean assignedActionAllowed = false;

            @Override
            public Boolean caseAbstractElement(AbstractElement object) {
                return assignedActionAllowed;
            }

            @Override
            public Boolean caseAlternatives(Alternatives object) {
                boolean wasActionAllowed = assignedActionAllowed;
                boolean localActionAllowed = true;
                for (AbstractElement element : object.getElements()) {
                    assignedActionAllowed = wasActionAllowed;
                    localActionAllowed &= doSwitch(element);
                }
                assignedActionAllowed = wasActionAllowed || (localActionAllowed && !GrammarUtil.isOptionalCardinality(object));
                return assignedActionAllowed;
            }

            @Override
            public Boolean caseUnorderedGroup(UnorderedGroup object) {
                boolean wasActionAllowed = assignedActionAllowed;
                boolean localActionAllowed = false;
                for (AbstractElement element : object.getElements()) {
                    assignedActionAllowed = wasActionAllowed;
                    localActionAllowed |= doSwitch(element);
                }
                assignedActionAllowed = wasActionAllowed || (localActionAllowed && !GrammarUtil.isOptionalCardinality(object));
                return assignedActionAllowed;
            }

            @Override
            public Boolean caseAssignment(Assignment object) {
                assignedActionAllowed = assignedActionAllowed || !GrammarUtil.isOptionalCardinality(object);
                return assignedActionAllowed;
            }

            @Override
            public Boolean caseGroup(Group object) {
                boolean wasAssignedActionAllowed = assignedActionAllowed;
                for (AbstractElement element : object.getElements()) doSwitch(element);
                assignedActionAllowed = wasAssignedActionAllowed || (assignedActionAllowed && !GrammarUtil.isOptionalCardinality(object));
                return assignedActionAllowed;
            }

            @Override
            public Boolean caseAction(Action object) {
                if (object == action) {
                    if (!assignedActionAllowed) {
                        error("An action is not allowed in fragments and when the current may still be unassigned.", null);
                        checkDone();
                    }
                }
                assignedActionAllowed = true;
                return assignedActionAllowed;
            }

            @Override
            public Boolean caseRuleCall(RuleCall object) {
                if (object.getRule() == null)
                    return assignedActionAllowed;
                assignedActionAllowed = assignedActionAllowed || doSwitch(object.getRule()) && !GrammarUtil.isOptionalCardinality(object);
                return assignedActionAllowed;
            }

            @Override
            public Boolean caseParserRule(ParserRule object) {
                assignedActionAllowed = !GrammarUtil.isDatatypeRule(object) && !object.isFragment();
                return assignedActionAllowed;
            }

            @Override
            public Boolean caseTerminalRule(TerminalRule object) {
                return assignedActionAllowed;
            }
        };
        visitor.doSwitch(rule.getAlternatives());
    }
}