private static IComponentFactory GetComponentJson(IExceptionContext ectx, Type signatureType, string name, JObject settings, ModuleCatalog catalog)
        {
            Contracts.AssertValue(ectx);
            ectx.AssertValue(signatureType);
            ectx.AssertNonEmpty(name);
            ectx.AssertValueOrNull(settings);
            ectx.AssertValue(catalog);

            if (!catalog.TryGetComponentKind(signatureType, out string kind))
            {
                throw ectx.Except($"Component type '{signatureType}' is not a valid signature type.");
            }

            if (!catalog.TryFindComponent(kind, name, out ModuleCatalog.ComponentInfo component))
            {
                var available = catalog.GetAllComponents(kind).Select(x => $"'{x.Name}'");
                throw ectx.Except($"Component '{name}' of kind '{kind}' is not found. Available components are: {string.Join(", ", available)}");
            }

            var inputBuilder = new InputBuilder(ectx, component.ArgumentType, catalog);

            if (settings != null)
            {
                foreach (var pair in settings)
                {
                    if (!inputBuilder.TrySetValueJson(pair.Key, pair.Value))
                    {
                        throw ectx.Except($"Unexpected value for component '{name}', field '{pair.Key}': '{pair.Value}'");
                    }
                }
            }

            var missing = inputBuilder.GetMissingValues().ToArray();

            if (missing.Length > 0)
            {
                throw ectx.Except($"The following required inputs were not provided for component '{name}': {string.Join(", ", missing)}");
            }
            return(inputBuilder.GetInstance() as IComponentFactory);
        }
        private static object ParseJsonValue(IExceptionContext ectx, Type type, Attributes attributes, JToken value, ModuleCatalog catalog)
        {
            Contracts.AssertValue(ectx);
            ectx.AssertValue(type);
            ectx.AssertValueOrNull(value);
            ectx.AssertValue(catalog);

            if (value == null)
            {
                return(null);
            }

            if (value is JValue val && val.Value == null)
            {
                return(null);
            }

            if (type.IsGenericType && (type.GetGenericTypeDefinition() == typeof(Optional <>) || type.GetGenericTypeDefinition() == typeof(Nullable <>)))
            {
                type = type.GetGenericArguments()[0];
            }

            if (type.IsGenericType && (type.GetGenericTypeDefinition() == typeof(Var <>)))
            {
                string varName = value.Value <string>();
                ectx.Check(VariableBinding.IsBindingToken(value), "Variable name expected.");
                var variable   = Activator.CreateInstance(type) as IVarSerializationHelper;
                var varBinding = VariableBinding.Create(ectx, varName);
                variable.VarName = varBinding.VariableName;
                return(variable);
            }

            if (type == typeof(JArray) && value is JArray)
            {
                return(value);
            }

            TlcModule.DataKind dt = TlcModule.GetDataType(type);

            try
            {
                switch (dt)
                {
                case TlcModule.DataKind.Bool:
                    return(value.Value <bool>());

                case TlcModule.DataKind.String:
                    return(value.Value <string>());

                case TlcModule.DataKind.Char:
                    return(value.Value <char>());

                case TlcModule.DataKind.Enum:
                    if (!Enum.IsDefined(type, value.Value <string>()))
                    {
                        throw ectx.Except($"Requested value '{value.Value<string>()}' is not a member of the Enum type '{type.Name}'");
                    }
                    return(Enum.Parse(type, value.Value <string>()));

                case TlcModule.DataKind.Float:
                    if (type == typeof(double))
                    {
                        return(value.Value <double>());
                    }
                    else if (type == typeof(float))
                    {
                        return(value.Value <float>());
                    }
                    else
                    {
                        ectx.Assert(false);
                        throw ectx.ExceptNotSupp();
                    }

                case TlcModule.DataKind.Array:
                    var ja = value as JArray;
                    ectx.Check(ja != null, "Expected array value");
                    Func <IExceptionContext, JArray, Attributes, ModuleCatalog, object> makeArray = MakeArray <int>;
                    return(Utils.MarshalInvoke(makeArray, type.GetElementType(), ectx, ja, attributes, catalog));

                case TlcModule.DataKind.Int:
                    if (type == typeof(long))
                    {
                        return(value.Value <long>());
                    }
                    if (type == typeof(int))
                    {
                        return(value.Value <int>());
                    }
                    ectx.Assert(false);
                    throw ectx.ExceptNotSupp();

                case TlcModule.DataKind.UInt:
                    if (type == typeof(ulong))
                    {
                        return(value.Value <ulong>());
                    }
                    if (type == typeof(uint))
                    {
                        return(value.Value <uint>());
                    }
                    ectx.Assert(false);
                    throw ectx.ExceptNotSupp();

                case TlcModule.DataKind.Dictionary:
                    ectx.Check(value is JObject, "Expected object value");
                    Func <IExceptionContext, JObject, Attributes, ModuleCatalog, object> makeDict = MakeDictionary <int>;
                    return(Utils.MarshalInvoke(makeDict, type.GetGenericArguments()[1], ectx, (JObject)value, attributes, catalog));

                case TlcModule.DataKind.Component:
                    var jo = value as JObject;
                    ectx.Check(jo != null, "Expected object value");
                    // REVIEW: consider accepting strings alone.
                    var jName = jo[FieldNames.Name];
                    ectx.Check(jName != null, "Field '" + FieldNames.Name + "' is required for component.");
                    ectx.Check(jName is JValue, "Expected '" + FieldNames.Name + "' field to be a string.");
                    var name = jName.Value <string>();
                    ectx.Check(jo[FieldNames.Settings] == null || jo[FieldNames.Settings] is JObject,
                               "Expected '" + FieldNames.Settings + "' field to be an object");
                    return(GetComponentJson(ectx, type, name, jo[FieldNames.Settings] as JObject, catalog));

                default:
                    var settings = value as JObject;
                    ectx.Check(settings != null, "Expected object value");
                    var inputBuilder = new InputBuilder(ectx, type, catalog);

                    if (inputBuilder._fields.Length == 0)
                    {
                        throw ectx.Except($"Unsupported input type: {dt}");
                    }

                    if (settings != null)
                    {
                        foreach (var pair in settings)
                        {
                            if (!inputBuilder.TrySetValueJson(pair.Key, pair.Value))
                            {
                                throw ectx.Except($"Unexpected value for component '{type}', field '{pair.Key}': '{pair.Value}'");
                            }
                        }
                    }

                    var missing = inputBuilder.GetMissingValues().ToArray();
                    if (missing.Length > 0)
                    {
                        throw ectx.Except($"The following required inputs were not provided for component '{type}': {string.Join(", ", missing)}");
                    }
                    return(inputBuilder.GetInstance());
                }
            }
            catch (FormatException ex)
            {
                if (ex.IsMarked())
                {
                    throw;
                }
                throw ectx.Except(ex, $"Failed to parse JSON value '{value}' as {type}");
            }
        }