// The Nova Project by Ken Beckett.
// Copyright (C) 2007-2012 Inevitable Software, all rights reserved.
// Released under the Common Development and Distribution License, CDDL-1.0: http://opensource.org/licenses/cddl1.php
using System;
using Nova.Parsing;
namespace Nova.CodeDOM
{
/// <summary>
/// The NotEqual operator checks if the left Expression is NOT equal to the right Expression.
/// </summary>
public class NotEqual : RelationalOperator
{
#region /* CONSTANTS */
/// <summary>
/// The internal name of the operator.
/// </summary>
public const string InternalName = NamePrefix + "Inequality";
#endregion
#region /* CONSTRUCTORS */
/// <summary>
/// Create a <see cref="NotEqual"/> operator.
/// </summary>
public NotEqual(Expression left, Expression right)
: base(left, right)
{ }
#endregion
#region /* PROPERTIES */
/// <summary>
/// The symbol associated with the operator.
/// </summary>
public override string Symbol
{
get { return ParseToken; }
}
#endregion
#region /* METHODS */
/// <summary>
/// The internal name of the <see cref="BinaryOperator"/>.
/// </summary>
public override string GetInternalName()
{
return InternalName;
}
#endregion
#region /* PARSING */
/// <summary>
/// The token used to parse the code object.
/// </summary>
public const string ParseToken = "!=";
/// <summary>
/// The precedence of the operator.
/// </summary>
public const int Precedence = 340;
/// <summary>
/// True if the operator is left-associative, or false if it's right-associative.
/// </summary>
public const bool LeftAssociative = true;
internal static new void AddParsePoints()
{
Parser.AddOperatorParsePoint(ParseToken, Precedence, LeftAssociative, false, Parse);
}
/// <summary>
/// Parse a <see cref="NotEqual"/> operator.
/// </summary>
public static NotEqual Parse(Parser parser, CodeObject parent, ParseFlags flags)
{
return new NotEqual(parser, parent);
}
protected NotEqual(Parser parser, CodeObject parent)
: base(parser, parent)
{ }
/// <summary>
/// Get the precedence of the operator.
/// </summary>
public override int GetPrecedence()
{
return Precedence;
}
#endregion
#region /* RESOLVING */
/// <summary>
/// Compare if the first constant object is not equal to the second.
/// Supported types are: string, bool, enum, decimal, double, float, ulong, long, uint, int, ushort, short, char, byte, sbyte.
/// </summary>
protected override object EvaluateConstants(object leftConstant, object rightConstant)
{
// Check for null constants
if (leftConstant == null || rightConstant == null)
{
if (leftConstant == null && rightConstant == null)
return false;
return null; // The operation is invalid
}
// Check for string, bool, or enum types
if (leftConstant is string || rightConstant is string)
{
if (leftConstant is string && rightConstant is string)
return ((string)leftConstant != (string)rightConstant);
return null; // The operation is invalid
}
if (leftConstant is bool || rightConstant is bool)
{
if (leftConstant is bool && rightConstant is bool)
return ((bool)leftConstant != (bool)rightConstant);
return null; // The operation is invalid
}
if (leftConstant is EnumConstant || rightConstant is EnumConstant)
{
if (leftConstant is EnumConstant && rightConstant is EnumConstant)
{
EnumConstant leftEnum = (EnumConstant)leftConstant;
EnumConstant rightEnum = (EnumConstant)rightConstant;
if (leftEnum.EnumTypeRef.IsSameRef(rightEnum.EnumTypeRef))
return EvaluateConstants(leftEnum.ConstantValue, rightEnum.ConstantValue);
}
return null; // The operation is invalid
}
// Do binary numeric promotions
if (leftConstant is decimal)
{
if (!(rightConstant is float || rightConstant is double))
return (decimal)leftConstant != Convert.ToDecimal(rightConstant);
return null; // The operation is invalid
}
if (rightConstant is decimal)
{
if (!(leftConstant is float || leftConstant is double))
return Convert.ToDecimal(leftConstant) != (decimal)rightConstant;
return null; // The operation is invalid
}
if (leftConstant is double)
return (double)leftConstant != Convert.ToDouble(rightConstant);
if (rightConstant is double)
return Convert.ToDouble(leftConstant) != (double)rightConstant;
if (leftConstant is float)
return (float)leftConstant != Convert.ToSingle(rightConstant);
if (rightConstant is float)
return Convert.ToSingle(leftConstant) != (float)rightConstant;
if (leftConstant is ulong)
{
if ((rightConstant is sbyte && (sbyte)rightConstant < 0) || (rightConstant is short && (short)rightConstant < 0)
|| (rightConstant is int && (int)rightConstant < 0) || (rightConstant is long && (long)rightConstant < 0))
return null; // The operation is invalid
return (ulong)leftConstant != Convert.ToUInt64(rightConstant);
}
if (rightConstant is ulong)
{
if ((leftConstant is sbyte && (sbyte)leftConstant < 0) || (leftConstant is short && (short)leftConstant < 0)
|| (leftConstant is int && (int)leftConstant < 0) || (leftConstant is long && (long)leftConstant < 0))
return null; // The operation is invalid
return Convert.ToUInt64(leftConstant) != (ulong)rightConstant;
}
if (leftConstant is long)
return (long)leftConstant != Convert.ToInt64(rightConstant);
if (rightConstant is long)
return Convert.ToInt64(leftConstant) != (long)rightConstant;
if (leftConstant is uint)
{
if ((rightConstant is sbyte && (sbyte)rightConstant < 0) || (rightConstant is short && (short)rightConstant < 0)
|| (rightConstant is int && (int)rightConstant < 0))
return Convert.ToInt64(leftConstant) != Convert.ToInt64(rightConstant);
return (uint)leftConstant != Convert.ToUInt32(rightConstant);
}
if (rightConstant is uint)
{
if ((leftConstant is sbyte && (sbyte)leftConstant < 0) || (leftConstant is short && (short)leftConstant < 0)
|| (leftConstant is int && (int)leftConstant < 0))
return Convert.ToInt64(leftConstant) != Convert.ToInt64(rightConstant);
return Convert.ToUInt32(leftConstant) != (uint)rightConstant;
}
// All other cases (with smaller integral types) get promoted to ints
return Convert.ToInt32(leftConstant) != Convert.ToInt32(rightConstant);
}
#endregion
}
}