Ejemplo n.º 1
0
        /// <summary>
        /// Attempts to coerce the operand types on a binary operation for some special type and value cases as treated by JsonValue:
        /// "true" and "false" can be converted to boolean.
        /// Guid, DateTime and other types can be converted to string.
        /// </summary>
        /// <param name="thisOperand">The first operand.</param>
        /// <param name="otherOperand">The second operand</param>
        /// <param name="coercedType">On success, this parameter contains the coerced type.</param>
        /// <returns>true if the coercion is performed, false otherwise.</returns>
        private static bool TryCoerceSpecialTypes(DynamicMetaObject thisOperand, DynamicMetaObject otherOperand, out Type coercedType)
        {
            JsonValue thisValue  = thisOperand.Value as JsonValue;
            JsonValue otherValue = otherOperand.Value as JsonValue;

            if (thisValue is JsonPrimitive)
            {
                Type thisType = thisValue.Read().GetType();

                if (thisType != otherOperand.LimitType)
                {
                    if (otherOperand.LimitType == typeof(string) || (thisType == typeof(string) && otherValue == null))
                    {
                        object value;
                        if (thisValue.TryReadAs(otherOperand.LimitType, out value))
                        {
                            coercedType = otherOperand.LimitType;
                            return(true);
                        }
                    }
                }
            }

            coercedType = default(Type);
            return(false);
        }
Ejemplo n.º 2
0
        /// <summary>
        /// Updates the <see cref="Expression"/> tree for the operands of the specified operation.
        /// </summary>
        /// <param name="operation">The operation to evalutes.</param>
        /// <param name="thisOperand">The first operand.</param>
        /// <param name="otherOperand">The second operand.</param>
        /// <param name="thisExpression">The <see cref="Expression"/> for the first operand.</param>
        /// <param name="otherExpression">The <see cref="Expression"/> for the second operand.</param>
        private static void GetBinaryOperandExpressions(ExpressionType operation, DynamicMetaObject thisOperand, DynamicMetaObject otherOperand, ref Expression thisExpression, ref Expression otherExpression)
        {
            JsonValue thisValue  = thisOperand.Value as JsonValue;
            JsonValue otherValue = otherOperand.Value as JsonValue;

            Type thisType  = thisValue.Read().GetType();
            Type otherType = otherValue != null?otherValue.Read().GetType() : otherOperand.Value.GetType();

            Type coercedType;

            if (JsonValueDynamicMetaObject.TryCoerceType(operation, thisType, otherType, out coercedType))
            {
                thisType = otherType = coercedType;
            }
            else if (JsonValueDynamicMetaObject.TryCoerceSpecialTypes(thisOperand, otherOperand, out coercedType))
            {
                thisType = otherType = coercedType;
            }

            thisExpression = Expression.Convert(thisExpression, thisOperand.LimitType);
            thisExpression = Expression.Convert(Expression.Call(thisExpression, ReadAsMethodInfo, new Expression[] { Expression.Constant(thisType) }), thisType);

            otherExpression = Expression.Convert(otherExpression, otherOperand.LimitType);
            if (otherValue != null)
            {
                otherExpression = Expression.Convert(Expression.Call(otherExpression, ReadAsMethodInfo, new Expression[] { Expression.Constant(otherType) }), otherType);
            }
            else if (otherOperand.LimitType != otherType)
            {
                otherExpression = Expression.Convert(otherExpression, otherType);
            }
        }
Ejemplo n.º 3
0
        /// <summary>
        /// Gets the return type for unary operations.
        /// </summary>
        /// <param name="binder">The unary operation binder.</param>
        /// <returns>The type representing the operation return type.</returns>
        private Type GetUnaryOperationReturnType(UnaryOperationBinder binder)
        {
            JsonValue thisValue = this.Value as JsonValue;

            Type returnType = binder.ReturnType == typeof(object) ? thisValue.Read().GetType() : binder.ReturnType;

            //// The DLR sets the binder.ReturnType for the unary 'Not' operation as 'object' as opposed to 'bool',
            //// we need to detect this case and fix up the type to enable boolean conversions from strings.

            if (returnType == typeof(string) && binder.Operation == ExpressionType.Not)
            {
                bool boolVal;
                if (thisValue.TryReadAs <bool>(out boolVal))
                {
                    returnType = typeof(bool);
                }
            }

            return(returnType);
        }