SqlConstantExpressionNode.cs

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// 
//  Copyright 2010-2015 Deveel
// 
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
// 
//        http://www.apache.org/licenses/LICENSE-2.0
// 
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
//

using System;

using Deveel.Data.Sql.Objects;

namespace Deveel.Data.Sql.Parser {
    class SqlConstantExpressionNode : SqlNode, IExpressionNode {
        internal SqlConstantExpressionNode() {
        }

        public ISqlObject Value { get; private set; }

        protected override ISqlNode OnChildNode(ISqlNode node) {
            if (node is SqlKeyNode) {
                var keyNode = (SqlKeyNode) node;
                if (String.Equals(keyNode.Text, "true", StringComparison.OrdinalIgnoreCase)) {
                    Value = SqlBoolean.True;
                } else if (String.Equals(keyNode.Text, "false", StringComparison.OrdinalIgnoreCase)) {
                    Value = SqlBoolean.False;
                } else if (String.Equals(keyNode.Text, "null", StringComparison.OrdinalIgnoreCase)) {
                    Value = SqlNull.Value;
                } else {
                    Value = new SqlString(((SqlKeyNode) node).Text.ToCharArray());
                }
            } else if (node is IntegerLiteralNode) {
                Value = new SqlNumber(((IntegerLiteralNode) node).BigValue);
            } else if (node is NumberLiteralNode) {
                Value = new SqlNumber(((NumberLiteralNode) node).BigValue);
            } else if (node is StringLiteralNode) {
                Value = new SqlString(((StringLiteralNode) node).Value.ToCharArray());
            }

            return base.OnChildNode(node);
        }
    }
}