/// <summary>
 ///     Constructor
 /// </summary>
 /// <param name="element">The element for which this explanation part is created</param>
 /// <param name="leftPart">The left path to associate to this explanation</param>
 /// <param name="rightPart">The value associate to this left part</param>
 public ExplanationPart(ModelElement element, object leftPart, INamable rightPart = null)
 {
     Element = element;
     LeftPart = leftPart;
     RightPart = rightPart;
     SubExplanations = new List<ExplanationPart>();
 }

 /// <summary>
 ///     Constructor
 /// </summary>
 /// <param name="id"></param>
 /// <param name="instance"></param>
 /// <param name="priority"></param>
 public ModelEvent(string id, INamable instance, acceptor.RulePriority? priority)
 {
     Id = id;
     Message = id;
     Instance = instance;
     Priority = priority;
 }

        /// <summary>
        ///     Predicate which indicates whether the namable provided matches the expectation for the semantic analysis
        /// </summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public override bool AcceptableChoice(INamable value)
        {
            bool retVal = base.AcceptableChoice(value);

            if (!retVal)
            {
                retVal = IsCallable.Predicate(value);
            }

            return retVal;
        }

        /// <summary>
        ///     Predicate which indicates whether the namable provided matches the expectation for the semantic analysis
        /// </summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public override bool AcceptableChoice(INamable value)
        {
            bool retVal = base.AcceptableChoice(value);

            if (!retVal)
            {
                return value is Parameter;
            }

            return retVal;
        }

        /// <summary>
        ///     Performs the semantic analysis of the expression
        /// </summary>
        /// <param name="instance">the reference instance on which this element should analysed</param>
        /// <paraparam name="expectation">Indicates the kind of element we are looking for</paraparam>
        /// <returns>True if semantic analysis should be continued</returns>
        public override bool SemanticAnalysis(INamable instance, BaseFilter expectation)
        {
            bool retVal = base.SemanticAnalysis(instance, expectation);

            if (retVal)
            {
                // Iterator expression
                IteratorExpression.SemanticAnalysis(instance, AllMatches.INSTANCE);
                StaticUsage.AddUsages(IteratorExpression.StaticUsage, Usage.ModeEnum.Read);
            }

            return retVal;
        }

        public Rename( INamable Target, string Title, bool ReadOnly )
            : this()
        {
            NamingTarget = Target;
            NewName.Text = Target.Name;
            NewName.IsReadOnly = ReadOnly;

            NewName.SelectAll();

            if ( !string.IsNullOrEmpty( Title ) )
            {
                TitleBlock.Text = Title;
            }
        }

        /// <summary>
        ///     Provides the possible references types for this expression (used in semantic analysis)
        /// </summary>
        /// <param name="instance">the reference instance on which this element should analysed</param>
        /// <param name="expectation">Indicates the kind of element we are looking for</param>
        /// <param name="last">indicates that this is the last element in a dereference chain</param>
        /// <returns></returns>
        public override ReturnValue GetReferenceTypes(INamable instance, BaseFilter expectation, bool last)
        {
            ReturnValue retVal = ReturnValue.Empty;

            if (Term != null)
            {
                retVal = Term.GetReferenceTypes(instance, expectation, last);
            }
            else
            {
                if (Expression != null)
                {
                    retVal = Expression.GetReferenceTypes(instance, expectation, true);
                }
            }

            return retVal;
        }

        /// <summary>
        ///     Provides the textual representation of the namable provided
        /// </summary>
        /// <param name="namable"></param>
        /// <returns></returns>
        private string explainNamable(INamable namable)
        {
            string retVal = "";

            if (namable != null)
            {
                retVal = namable.Name;

                Function fonction = namable as Function;
                if (fonction != null)
                {
                    if (fonction.Graph != null)
                    {
                        retVal = fonction.Graph.ToString();
                    }
                    else if (fonction.Surface != null)
                    {
                        retVal = fonction.Surface.ToString();
                    }
                }
                else
                {
                    IValue value = namable as IValue;
                    if (value != null)
                    {
                        retVal = value.LiteralName;
                    }
                }
            }

            return retVal;
        }

        /// <summary>
        ///     Performs the semantic analysis of the statement
        /// </summary>
        /// <param name="instance">the reference instance on which this element should analysed</param>
        /// <returns>True if semantic analysis should be continued</returns>
        public override bool SemanticAnalysis(INamable instance = null)
        {
            bool retVal = base.SemanticAnalysis(instance);

            if (retVal)
            {
                // ListExpression
                if (ListExpression != null)
                {
                    ListExpression.SemanticAnalysis(instance);
                    StaticUsage.AddUsages(ListExpression.StaticUsage, Usage.ModeEnum.ReadAndWrite);

                    Collection collectionType = ListExpression.GetExpressionType() as Collection;
                    if (collectionType != null)
                    {
                        IteratorVariable.Type = collectionType.Type;
                    }
                }
                else
                {
                    AddError("List expression not provided");
                }

                // Condition
                if (Condition != null)
                {
                    Condition.SemanticAnalysis(instance);
                    StaticUsage.AddUsages(Condition.StaticUsage, Usage.ModeEnum.Read);
                }
            }

            return retVal;
        }

        /// <summary>
        ///     Provides the enclosing sub declarator
        /// </summary>
        /// <param name="instance"></param>
        /// <returns></returns>
        private INamable EnclosingSubDeclarator(INamable instance)
        {
            INamable retVal = instance;

            do
            {
                retVal = enclosing(retVal);
            } while (retVal != null && !(retVal is ISubDeclarator));

            return retVal;
        }

        /// <summary>
        ///     Adds a reference which satisfies the provided expectation in the result set
        /// </summary>
        /// <param name="namable"></param>
        /// <param name="expectation"></param>
        /// <param name="asType">Indicates that we had to move from instance to type to perform the deferencing</param>
        /// <param name="resultSet"></param>
        private int addReference(INamable namable, BaseFilter expectation, bool asType, ReturnValue resultSet)
        {
            int retVal = 0;

            if (namable != null)
            {
                if (expectation.AcceptableChoice(namable))
                {
                    if (asType)
                    {
                        if (!(namable is IValue) && !(namable is Type))
                        {
                            resultSet.Add(namable);
                            retVal += 1;
                        }
                        else if (namable is State)
                        {
                            // TODO : Refactor model to avoid this
                            resultSet.Add(namable);
                            retVal += 1;
                        }
                    }
                    else
                    {
                        resultSet.Add(namable);
                        retVal += 1;
                    }
                }
            }

            return retVal;
        }

        /// <summary>
        ///     Provides the possible references for this designator (only available during semantic analysis)
        /// </summary>
        /// <param name="instance">the instance on which this element should be found.</param>
        /// <param name="expectation">the expectation on the element found</param>
        /// <param name="lastElement">Indicates that this element is the last one in a dereference chain</param>
        /// <returns></returns>
        public ReturnValue GetReferences(INamable instance, BaseFilter expectation, bool lastElement)
        {
            ReturnValue retVal = new ReturnValue(this);

            if (instance == null)
            {
                // Special handling for THIS or ENCLOSING
                if (Image == ThisKeyword || Image == EnclosingKeyword)
                {
                    INamable currentElem = Root;
                    while (currentElem != null)
                    {
                        Type type = currentElem as Type;
                        if (type != null)
                        {
                            StateMachine stateMachine = type as StateMachine;
                            while (stateMachine != null)
                            {
                                type = stateMachine;
                                stateMachine = stateMachine.EnclosingStateMachine;
                            }

                            // Enclosing does not references state machines.
                            if (!(Image == EnclosingKeyword && type is StateMachine))
                            {
                                retVal.Add(type);
                                return retVal;
                            }
                        }
                        currentElem = enclosing(currentElem);
                    }

                    return retVal;
                }

                // No enclosing instance. Try to first name of a . separated list of names
                //  . First in the enclosing expression
                InterpreterTreeNode current = this;
                while (current != null)
                {
                    ISubDeclarator subDeclarator = current as ISubDeclarator;
                    if (FillBySubdeclarator(subDeclarator, expectation, false, retVal) > 0)
                    {
                        // If this is the last element in the dereference chain, stop at first match
                        if (lastElement)
                        {
                            return retVal;
                        }
                        current = null;
                    }
                    else
                    {
                        current = current.Enclosing;
                    }
                }

                // . In the predefined elements
                addReference(EfsSystem.Instance.GetPredefinedItem(Image), expectation, false, retVal);
                if (lastElement && !retVal.IsEmpty)
                {
                    return retVal;
                }

                // . In the enclosing items, except the enclosing dictionary since dictionaries are handled in a later step
                INamable currentNamable = Root;
                while (currentNamable != null)
                {
                    ISubDeclarator subDeclarator = currentNamable as ISubDeclarator;
                    if (subDeclarator != null && !(subDeclarator is Dictionary))
                    {
                        if (FillBySubdeclarator(subDeclarator, expectation, false, retVal) > 0 && lastElement)
                        {
                            return retVal;
                        }
                    }

                    currentNamable = EnclosingSubDeclarator(currentNamable);
                }

                // . In the dictionaries declared in the system
                foreach (Dictionary dictionary in EfsSystem.Instance.Dictionaries)
                {
                    if (FillBySubdeclarator(dictionary, expectation, false, retVal) > 0 && lastElement)
                    {
                        return retVal;
                    }

                    NameSpace defaultNameSpace = dictionary.FindNameSpace("Default");
                    if (defaultNameSpace != null)
                    {
                        if (FillBySubdeclarator(defaultNameSpace, expectation, false, retVal) > 0 && lastElement)
                        {
                            return retVal;
//.........这里部分代码省略.........

 /// <summary>
 ///     Predicate, so that the code can be reused
 /// </summary>
 /// <param name="value"></param>
 /// <returns></returns>
 public static bool Predicate(INamable value)
 {
     return value is Type;
 }

 /// <summary>
 ///     Predicate, so that the code can be reused
 /// </summary>
 /// <param name="value"></param>
 /// <returns></returns>
 public static bool Predicate(INamable value)
 {
     return (value is IValue);
 }

        /// <summary>
        ///     Performs the semantic analysis of the expression
        /// </summary>
        /// <param name="instance">the reference instance on which this element should analysed</param>
        /// <param name="expectation">Indicates the kind of element we are looking for</param>
        /// <returns>True if semantic analysis should be continued</returns>
        public override bool SemanticAnalysis(INamable instance, BaseFilter expectation)
        {
            bool retVal = base.SemanticAnalysis(instance, expectation);

            if (retVal)
            {
                // Accumulator
                if (AccumulatorVariable != null)
                {
                    AccumulatorVariable.Type = GetExpressionType();
                }

                if (DefinedAccumulator != null)
                {
                    DefinedAccumulator.SemanticAnalysis(instance, AllMatches.INSTANCE);
                }

                if (Accumulator != null)
                {
                    Accumulator.SemanticAnalysis(instance, AllMatches.INSTANCE);
                    StaticUsage.AddUsages(Accumulator.StaticUsage, Usage.ModeEnum.Read);
                }
            }

            return retVal;
        }

        /// <summary>
        ///     Performs the semantic analysis of the expression
        /// </summary>
        /// <param name="instance">the reference instance on which this element should analysed</param>
        /// <paraparam name="expectation">Indicates the kind of element we are looking for</paraparam>
        /// <returns>True if semantic analysis should be continued</returns>
        public override bool SemanticAnalysis(INamable instance, BaseFilter expectation)
        {
            bool retVal = base.SemanticAnalysis(instance, expectation);

            if (retVal)
            {
                Ref = null;

                ReturnValue tmp = getReferences(instance, expectation, false);

                if (tmp.IsUnique)
                {
                    // Unique element has been found. Reference it and perform the semantic analysis
                    // on all dereferenced expression, now that the context is known for each expression
                    Ref = tmp.Values[0].Value;
                    StaticUsage.AddUsage(Ref, Root, null);

                    References referenceFilter;
                    ReturnValueElement current = tmp.Values[0];
                    for (int i = Arguments.Count - 1; i > 0; i--)
                    {
                        referenceFilter = new References(current.Value);
                        current = current.PreviousElement;
                        Arguments[i].SemanticAnalysis(current.Value, referenceFilter);
                        StaticUsage.AddUsages(Arguments[i].StaticUsage, null);
                        StaticUsage.AddUsage(Arguments[i].Ref, Root, null);
                    }
                    referenceFilter = new References(current.Value);
                    Arguments[0].SemanticAnalysis(null, referenceFilter);
                    StaticUsage.AddUsages(Arguments[0].StaticUsage, null);
                    StaticUsage.AddUsage(Arguments[0].Ref, Root, null);
                }
                else if (tmp.IsAmbiguous)
                {
                    // Several possible interpretations for this deref expression, not allowed
                    AddError("Expression " + ToString() + " may have several interpretations " + tmp.ToString() +
                             ", please disambiguate");
                }
                else
                {
                    // No possible interpretation for this deref expression, not allowed
                    AddError("Expression " + ToString() + " has no interpretation");
                }
            }

            return retVal;
        }

        /// <summary>
        ///     Provides the possible references for this expression (only available during semantic analysis)
        /// </summary>
        /// <param name="instance">the instance on which this element should be found.</param>
        /// <param name="expectation">the expectation on the element found</param>
        /// <param name="last">indicates that this is the last element in a dereference chain</param>
        /// <returns></returns>
        public override ReturnValue getReferences(INamable instance, BaseFilter expectation, bool last)
        {
            ReturnValue retVal = Arguments[0].getReferences(instance, AllMatches.INSTANCE, false);

            if (retVal.IsEmpty)
            {
                retVal = Arguments[0].getReferenceTypes(instance, AllMatches.INSTANCE, false);
            }

            // When variables & parameters are found, only consider the first one
            // which is the one that is closer in the tree
            {
                ReturnValue tmp2 = retVal;
                retVal = new ReturnValue();

                ReturnValueElement variable = null;
                foreach (ReturnValueElement elem in tmp2.Values)
                {
                    if (elem.Value is Parameter || elem.Value is IVariable)
                    {
                        if (variable == null)
                        {
                            variable = elem;
                            retVal.Values.Add(elem);
                        }
                    }
                    else
                    {
                        retVal.Values.Add(elem);
                    }
                }
            }

            if (!retVal.IsEmpty)
            {
                for (int i = 1; i < Arguments.Count; i++)
                {
                    ReturnValue tmp2 = retVal;
                    retVal = new ReturnValue(Arguments[i]);

                    foreach (ReturnValueElement elem in tmp2.Values)
                    {
                        bool removed = false;
                        ModelElement model = elem.Value as ModelElement;
                        if (model != null)
                        {
                            removed = model.IsRemoved;
                        }

                        if (!removed)
                        {
                            retVal.Merge(elem,
                                Arguments[i].getReferences(elem.Value, AllMatches.INSTANCE, i == (Arguments.Count - 1)));
                        }
                    }

                    if (retVal.IsEmpty)
                    {
                        AddError("Cannot find " + Arguments[i].ToString() + " in " + Arguments[i - 1].ToString());
                    }
                }
            }
            else
            {
                AddError("Cannot evaluate " + Arguments[0].ToString());
            }

            retVal.filter(expectation);

            return retVal;
        }

        /// <summary>
        ///     Performs the semantic analysis of the expression
        /// </summary>
        /// <param name="instance">the reference instance on which this element should analysed</param>
        /// <param name="expectation">Indicates the kind of element we are looking for</param>
        /// <returns>True if semantic analysis should be continued</returns>
        public override bool SemanticAnalysis(INamable instance, BaseFilter expectation)
        {
            bool retVal = base.SemanticAnalysis(instance, expectation);

            if (retVal)
            {
                // Structure
                if (Structure != null)
                {
                    Structure.SemanticAnalysis(instance, IsStructure.INSTANCE);
                    StaticUsage.AddUsages(Structure.StaticUsage, Usage.ModeEnum.Type);

                    // Structure field Association
                    if (Associations != null)
                    {
                        Structure structureType = Structure.Ref as Structure;
                        foreach (KeyValuePair<Designator, Expression> pair in Associations)
                        {
                            if (structureType != null)
                            {
                                pair.Key.Ref = structureType.FindStructureElement(pair.Key.Image);
                                StaticUsage.AddUsage(pair.Key.Ref, Root, Usage.ModeEnum.Parameter);
                            }

                            pair.Value.SemanticAnalysis(instance, IsRightSide.INSTANCE);
                            StaticUsage.AddUsages(pair.Value.StaticUsage, Usage.ModeEnum.Read);
                        }
                    }
                }
            }

            return retVal;
        }

        /// <summary>
        ///     Performs the semantic analysis of the expression
        /// </summary>
        /// <param name="instance">the reference instance on which this element should analysed</param>
        /// <param name="expectation">Indicates the kind of element we are looking for</param>
        /// <returns>True if semantic analysis should be continued</returns>
        public override bool SemanticAnalysis(INamable instance, BaseFilter expectation)
        {
            bool retVal = base.SemanticAnalysis(instance, expectation);

            if (retVal)
            {
                if (Term != null)
                {
                    Term.SemanticAnalysis(instance, expectation, true);
                    StaticUsage = Term.StaticUsage;
                }
                else if (Expression != null)
                {
                    Expression.SemanticAnalysis(instance, expectation);
                    StaticUsage = Expression.StaticUsage;
                }
            }

            return retVal;
        }

 /// <summary>
 ///     Predicate which indicates whether the namable provided matches the expectation for the semantic analysis
 /// </summary>
 /// <param name="value"></param>
 /// <returns></returns>
 public override bool AcceptableChoice(INamable value)
 {
     return Predicate(value);
 }