예제 #1
0
        public override AstNode Visit(AsExpression node)
        {
            // Begin the node.
            builder.BeginNode(node);

            // Get the target type and value.
            //Expression target = node.GetTarget();
            Expression value = node.GetValue();

            // Visit them.
            //target.Accept(this);
            value.Accept(this);

            // Get their types.
            IChelaType targetType = node.GetNodeType();
            IChelaType valueType = value.GetNodeType();
            if(targetType != valueType)
                Cast(node, value.GetNodeValue(), valueType, targetType, false);

            return builder.EndNode();
        }
예제 #2
0
        public override AstNode Visit(AsExpression node)
        {
            // Get the target type and value.
            Expression target = node.GetTarget();
            Expression value = node.GetValue();

            // Visit them.
            target.Accept(this);
            value.Accept(this);

            // The value must be a reference.
            IChelaType valueType = value.GetNodeType();
            node.SetCoercionType(valueType);
            if(!valueType.IsReference())
                Error(node, "expected reference value.");

            // De-ref the value.
            valueType = DeReferenceType(valueType);
            if(valueType.IsReference())
                node.SetCoercionType(valueType);

            // De-ref again.
            valueType = DeReferenceType(valueType);
            if(!valueType.IsPassedByReference())
                Error(node, "expeceted a reference value.");

            // Get the target type.
            IChelaType targetType = target.GetNodeType();
            targetType = ExtractActualType(target, targetType);
            if(!targetType.IsPassedByReference())
                Error(node, "as operator only can be used with reference types.");
            targetType = ReferenceType.Create(targetType);

            // TODO: Check if it is possible to perform the cast.

            // Set the node type.
            node.SetNodeType(targetType);

            return node;
        }