source: branches/2893_BNLR/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/Resolver/CSharpOperators.cs

// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
// 
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// software and associated documentation files (the "Software"), to deal in the Software
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// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ICSharpCode.NRefactory.TypeSystem;
using ICSharpCode.NRefactory.TypeSystem.Implementation;
using ICSharpCode.NRefactory.Utils;

namespace ICSharpCode.NRefactory.CSharp.Resolver
{
  sealed class CSharpOperators
  {
    readonly ICompilation compilation;
    
    private CSharpOperators(ICompilation compilation)
    {
      this.compilation = compilation;
      InitParameterArrays();
    }
    
    /// <summary>
    /// Gets the CSharpOperators instance for the specified <see cref="ICompilation"/>.
    /// This will make use of the context's cache manager (if available) to reuse the CSharpOperators instance.
    /// </summary>
    public static CSharpOperators Get(ICompilation compilation)
    {
      CacheManager cache = compilation.CacheManager;
      CSharpOperators operators = (CSharpOperators)cache.GetShared(typeof(CSharpOperators));
      if (operators == null) {
        operators = (CSharpOperators)cache.GetOrAddShared(typeof(CSharpOperators), new CSharpOperators(compilation));
      }
      return operators;
    }
    
    #region class OperatorMethod
    OperatorMethod[] Lift(params OperatorMethod[] methods)
    {
      List<OperatorMethod> result = new List<OperatorMethod>(methods);
      foreach (OperatorMethod method in methods) {
        OperatorMethod lifted = method.Lift(this);
        if (lifted != null)
          result.Add(lifted);
      }
      return result.ToArray();
    }
    
    IParameter[] normalParameters = new IParameter[(int)(TypeCode.String + 1 - TypeCode.Object)];
    IParameter[] nullableParameters = new IParameter[(int)(TypeCode.Decimal + 1 - TypeCode.Boolean)];
    
    void InitParameterArrays()
    {
      for (TypeCode i = TypeCode.Object; i <= TypeCode.String; i++) {
        normalParameters[i - TypeCode.Object] = new DefaultParameter(compilation.FindType(i), string.Empty);
      }
      for (TypeCode i = TypeCode.Boolean; i <= TypeCode.Decimal; i++) {
        IType type = NullableType.Create(compilation, compilation.FindType(i));
        nullableParameters[i - TypeCode.Boolean] = new DefaultParameter(type, string.Empty);
      }
    }
    
    IParameter MakeParameter(TypeCode code)
    {
      return normalParameters[code - TypeCode.Object];
    }
    
    IParameter MakeNullableParameter(IParameter normalParameter)
    {
      for (TypeCode i = TypeCode.Boolean; i <= TypeCode.Decimal; i++) {
        if (normalParameter == normalParameters[i - TypeCode.Object])
          return nullableParameters[i - TypeCode.Boolean];
      }
      throw new ArgumentException();
    }
    
    internal class OperatorMethod : IParameterizedMember
    {
      readonly ICompilation compilation;
      readonly IList<IParameter> parameters = new List<IParameter>();
      
      protected OperatorMethod(ICompilation compilation)
      {
        this.compilation = compilation;
      }
      
      public IList<IParameter> Parameters {
        get { return parameters; }
      }
      
      public IType ReturnType { get; internal set; }
      
      public ICompilation Compilation {
        get { return compilation; }
      }
      
      public virtual OperatorMethod Lift(CSharpOperators operators)
      {
        return null;
      }
      
      ITypeDefinition IEntity.DeclaringTypeDefinition {
        get { return null; }
      }
      
      IType IEntity.DeclaringType {
        get { return SpecialType.UnknownType; }
      }
      
      IMember IMember.MemberDefinition {
        get { return this; }
      }
      
      IUnresolvedMember IMember.UnresolvedMember {
        get { return null; }
      }
      
      IList<IMember> IMember.ImplementedInterfaceMembers {
        get { return EmptyList<IMember>.Instance; }
      }
      
      bool IMember.IsVirtual {
        get { return false; }
      }
      
      bool IMember.IsOverride {
        get { return false; }
      }
      
      bool IMember.IsOverridable {
        get { return false; }
      }
      
      SymbolKind ISymbol.SymbolKind {
        get { return SymbolKind.Operator; }
      }
      
      [Obsolete("Use the SymbolKind property instead.")]
      EntityType IEntity.EntityType {
        get { return EntityType.Operator; }
      }
      
      DomRegion IEntity.Region {
        get { return DomRegion.Empty; }
      }
      
      DomRegion IEntity.BodyRegion {
        get { return DomRegion.Empty; }
      }
      
      IList<IAttribute> IEntity.Attributes {
        get { return EmptyList<IAttribute>.Instance; }
      }
      
      Documentation.DocumentationComment IEntity.Documentation {
        get { return null; }
      }
      
      Accessibility IHasAccessibility.Accessibility {
        get { return Accessibility.Public; }
      }
      
      bool IEntity.IsStatic {
        get { return true; }
      }
      
      bool IEntity.IsAbstract {
        get { return false; }
      }
      
      bool IEntity.IsSealed {
        get { return false; }
      }
      
      bool IEntity.IsShadowing {
        get { return false; }
      }
      
      bool IEntity.IsSynthetic {
        get { return true; }
      }
      
      bool IHasAccessibility.IsPrivate {
        get { return false; }
      }
      
      bool IHasAccessibility.IsPublic {
        get { return true; }
      }
      
      bool IHasAccessibility.IsProtected {
        get { return false; }
      }
      
      bool IHasAccessibility.IsInternal {
        get { return false; }
      }
      
      bool IHasAccessibility.IsProtectedOrInternal {
        get { return false; }
      }
      
      bool IHasAccessibility.IsProtectedAndInternal {
        get { return false; }
      }
      
      bool IMember.IsExplicitInterfaceImplementation {
        get { return false; }
      }
      
      IAssembly IEntity.ParentAssembly {
        get { return compilation.MainAssembly; }
      }
      
      IMemberReference IMember.ToMemberReference()
      {
        throw new NotSupportedException();
      }
      
      ISymbolReference ISymbol.ToReference()
      {
        throw new NotSupportedException();
      }
      
      IMemberReference IMember.ToReference()
      {
        throw new NotSupportedException();
      }

      TypeParameterSubstitution IMember.Substitution {
        get {
          return TypeParameterSubstitution.Identity;
        }
      }

      IMember IMember.Specialize(TypeParameterSubstitution substitution)
      {
        if (TypeParameterSubstitution.Identity.Equals(substitution))
          return this;
        throw new NotSupportedException();
      }

      string INamedElement.FullName {
        get { return "operator"; }
      }
      
      public string Name {
        get { return "operator"; }
      }
      
      string INamedElement.Namespace {
        get { return string.Empty; }
      }
      
      string INamedElement.ReflectionName {
        get { return "operator"; }
      }
      
      public override string ToString()
      {
        StringBuilder b = new StringBuilder();
        b.Append(ReturnType + " operator(");
        for (int i = 0; i < parameters.Count; i++) {
          if (i > 0)
            b.Append(", ");
          b.Append(parameters[i].Type);
        }
        b.Append(')');
        return b.ToString();
      }
    }
    #endregion
    
    #region Unary operator class definitions
    internal class UnaryOperatorMethod : OperatorMethod
    {
      public virtual bool CanEvaluateAtCompileTime { get { return false; } }
      
      public virtual object Invoke(CSharpResolver resolver, object input)
      {
        throw new NotSupportedException();
      }
      
      public UnaryOperatorMethod(ICompilation compilaton) : base(compilaton)
      {
      }
    }
    
    sealed class LambdaUnaryOperatorMethod<T> : UnaryOperatorMethod
    {
      readonly Func<T, T> func;
      
      public LambdaUnaryOperatorMethod(CSharpOperators operators, Func<T, T> func)
        : base(operators.compilation)
      {
        TypeCode typeCode = Type.GetTypeCode(typeof(T));
        this.ReturnType = operators.compilation.FindType(typeCode);
        this.Parameters.Add(operators.MakeParameter(typeCode));
        this.func = func;
      }
      
      public override bool CanEvaluateAtCompileTime {
        get { return true; }
      }
      
      public override object Invoke(CSharpResolver resolver, object input)
      {
        if (input == null)
          return null;
        return func((T)resolver.CSharpPrimitiveCast(Type.GetTypeCode(typeof(T)), input));
      }
      
      public override OperatorMethod Lift(CSharpOperators operators)
      {
        return new LiftedUnaryOperatorMethod(operators, this);
      }
    }
    
    sealed class LiftedUnaryOperatorMethod : UnaryOperatorMethod, OverloadResolution.ILiftedOperator
    {
      UnaryOperatorMethod baseMethod;
      
      public LiftedUnaryOperatorMethod(CSharpOperators operators, UnaryOperatorMethod baseMethod) : base(operators.compilation)
      {
        this.baseMethod = baseMethod;
        this.ReturnType = NullableType.Create(baseMethod.Compilation, baseMethod.ReturnType);
        this.Parameters.Add(operators.MakeNullableParameter(baseMethod.Parameters[0]));
      }
      
      public IList<IParameter> NonLiftedParameters {
        get { return baseMethod.Parameters; }
      }
    }
    #endregion
    
    #region Unary operator definitions
    // C# 4.0 spec: §7.7.1 Unary plus operator
    OperatorMethod[] unaryPlusOperators;
    
    public OperatorMethod[] UnaryPlusOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref unaryPlusOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref unaryPlusOperators, Lift(
            new LambdaUnaryOperatorMethod<int>    (this, i => +i),
            new LambdaUnaryOperatorMethod<uint>   (this, i => +i),
            new LambdaUnaryOperatorMethod<long>   (this, i => +i),
            new LambdaUnaryOperatorMethod<ulong>  (this, i => +i),
            new LambdaUnaryOperatorMethod<float>  (this, i => +i),
            new LambdaUnaryOperatorMethod<double> (this, i => +i),
            new LambdaUnaryOperatorMethod<decimal>(this, i => +i)
          ));
        }
      }
    }
    
    // C# 4.0 spec: §7.7.2 Unary minus operator
    OperatorMethod[] uncheckedUnaryMinusOperators;
    
    public OperatorMethod[] UncheckedUnaryMinusOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref uncheckedUnaryMinusOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref uncheckedUnaryMinusOperators, Lift(
            new LambdaUnaryOperatorMethod<int>    (this, i => unchecked(-i)),
            new LambdaUnaryOperatorMethod<long>   (this, i => unchecked(-i)),
            new LambdaUnaryOperatorMethod<float>  (this, i => unchecked(-i)),
            new LambdaUnaryOperatorMethod<double> (this, i => unchecked(-i)),
            new LambdaUnaryOperatorMethod<decimal>(this, i => unchecked(-i))
          ));
        }
      }
    }
    
    OperatorMethod[] checkedUnaryMinusOperators;
    
    public OperatorMethod[] CheckedUnaryMinusOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref checkedUnaryMinusOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref checkedUnaryMinusOperators, Lift(
            new LambdaUnaryOperatorMethod<int>    (this, i => checked(-i)),
            new LambdaUnaryOperatorMethod<long>   (this, i => checked(-i)),
            new LambdaUnaryOperatorMethod<float>  (this, i => checked(-i)),
            new LambdaUnaryOperatorMethod<double> (this, i => checked(-i)),
            new LambdaUnaryOperatorMethod<decimal>(this, i => checked(-i))
          ));
        }
      }
    }
    
    // C# 4.0 spec: §7.7.3 Logical negation operator
    OperatorMethod[] logicalNegationOperators;
    
    public OperatorMethod[] LogicalNegationOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref logicalNegationOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref logicalNegationOperators, Lift(
            new LambdaUnaryOperatorMethod<bool>(this, b => !b)
          ));
        }
      }
    }
    
    // C# 4.0 spec: §7.7.4 Bitwise complement operator
    OperatorMethod[] bitwiseComplementOperators;
    
    public OperatorMethod[] BitwiseComplementOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref bitwiseComplementOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref bitwiseComplementOperators, Lift(
            new LambdaUnaryOperatorMethod<int>  (this, i => ~i),
            new LambdaUnaryOperatorMethod<uint> (this, i => ~i),
            new LambdaUnaryOperatorMethod<long> (this, i => ~i),
            new LambdaUnaryOperatorMethod<ulong>(this, i => ~i)
          ));
        }
      }
    }
    #endregion
    
    #region Binary operator class definitions
    internal class BinaryOperatorMethod : OperatorMethod
    {
      public virtual bool CanEvaluateAtCompileTime { get { return false; } }
      public virtual object Invoke(CSharpResolver resolver, object lhs, object rhs) {
        throw new NotSupportedException();
      }
      
      public BinaryOperatorMethod(ICompilation compilation) : base(compilation) {}
    }
    
    sealed class LambdaBinaryOperatorMethod<T1, T2> : BinaryOperatorMethod
    {
      readonly Func<T1, T2, T1> checkedFunc;
      readonly Func<T1, T2, T1> uncheckedFunc;
      
      public LambdaBinaryOperatorMethod(CSharpOperators operators, Func<T1, T2, T1> func)
        : this(operators, func, func)
      {
      }
      
      public LambdaBinaryOperatorMethod(CSharpOperators operators, Func<T1, T2, T1> checkedFunc, Func<T1, T2, T1> uncheckedFunc)
        : base(operators.compilation)
      {
        TypeCode t1 = Type.GetTypeCode(typeof(T1));
        this.ReturnType = operators.compilation.FindType(t1);
        this.Parameters.Add(operators.MakeParameter(t1));
        this.Parameters.Add(operators.MakeParameter(Type.GetTypeCode(typeof(T2))));
        this.checkedFunc = checkedFunc;
        this.uncheckedFunc = uncheckedFunc;
      }
      
      public override bool CanEvaluateAtCompileTime {
        get { return true; }
      }
      
      public override object Invoke(CSharpResolver resolver, object lhs, object rhs)
      {
        if (lhs == null || rhs == null)
          return null;
        Func<T1, T2, T1> func = resolver.CheckForOverflow ? checkedFunc : uncheckedFunc;
        return func((T1)resolver.CSharpPrimitiveCast(Type.GetTypeCode(typeof(T1)), lhs),
                    (T2)resolver.CSharpPrimitiveCast(Type.GetTypeCode(typeof(T2)), rhs));
      }
      
      public override OperatorMethod Lift(CSharpOperators operators)
      {
        return new LiftedBinaryOperatorMethod(operators, this);
      }
    }
    
    sealed class LiftedBinaryOperatorMethod : BinaryOperatorMethod, OverloadResolution.ILiftedOperator
    {
      readonly BinaryOperatorMethod baseMethod;
      
      public LiftedBinaryOperatorMethod(CSharpOperators operators, BinaryOperatorMethod baseMethod)
        : base(operators.compilation)
      {
        this.baseMethod = baseMethod;
        this.ReturnType = NullableType.Create(operators.compilation, baseMethod.ReturnType);
        this.Parameters.Add(operators.MakeNullableParameter(baseMethod.Parameters[0]));
        this.Parameters.Add(operators.MakeNullableParameter(baseMethod.Parameters[1]));
      }
      
      public IList<IParameter> NonLiftedParameters {
        get { return baseMethod.Parameters; }
      }
    }
    #endregion
    
    #region Arithmetic operators
    // C# 4.0 spec: §7.8.1 Multiplication operator
    
    OperatorMethod[] multiplicationOperators;
    
    public OperatorMethod[] MultiplicationOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref multiplicationOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref multiplicationOperators, Lift(
            new LambdaBinaryOperatorMethod<int,     int>    (this, (a, b) => checked(a * b), (a, b) => unchecked(a * b)),
            new LambdaBinaryOperatorMethod<uint,    uint>   (this, (a, b) => checked(a * b), (a, b) => unchecked(a * b)),
            new LambdaBinaryOperatorMethod<long,    long>   (this, (a, b) => checked(a * b), (a, b) => unchecked(a * b)),
            new LambdaBinaryOperatorMethod<ulong,   ulong>  (this, (a, b) => checked(a * b), (a, b) => unchecked(a * b)),
            new LambdaBinaryOperatorMethod<float,   float>  (this, (a, b) => checked(a * b), (a, b) => unchecked(a * b)),
            new LambdaBinaryOperatorMethod<double,  double> (this, (a, b) => checked(a * b), (a, b) => unchecked(a * b)),
            new LambdaBinaryOperatorMethod<decimal, decimal>(this, (a, b) => checked(a * b), (a, b) => unchecked(a * b))
          ));
        }
      }
    }
    
    // C# 4.0 spec: §7.8.2 Division operator
    OperatorMethod[] divisionOperators;
    
    public OperatorMethod[] DivisionOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref divisionOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref divisionOperators, Lift(
            new LambdaBinaryOperatorMethod<int,     int>    (this, (a, b) => checked(a / b), (a, b) => unchecked(a / b)),
            new LambdaBinaryOperatorMethod<uint,    uint>   (this, (a, b) => checked(a / b), (a, b) => unchecked(a / b)),
            new LambdaBinaryOperatorMethod<long,    long>   (this, (a, b) => checked(a / b), (a, b) => unchecked(a / b)),
            new LambdaBinaryOperatorMethod<ulong,   ulong>  (this, (a, b) => checked(a / b), (a, b) => unchecked(a / b)),
            new LambdaBinaryOperatorMethod<float,   float>  (this, (a, b) => checked(a / b), (a, b) => unchecked(a / b)),
            new LambdaBinaryOperatorMethod<double,  double> (this, (a, b) => checked(a / b), (a, b) => unchecked(a / b)),
            new LambdaBinaryOperatorMethod<decimal, decimal>(this, (a, b) => checked(a / b), (a, b) => unchecked(a / b))
          ));
        }
      }
    }
    
    // C# 4.0 spec: §7.8.3 Remainder operator
    OperatorMethod[] remainderOperators;
    
    public OperatorMethod[] RemainderOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref remainderOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref remainderOperators, Lift(
            new LambdaBinaryOperatorMethod<int,     int>    (this, (a, b) => checked(a % b), (a, b) => unchecked(a % b)),
            new LambdaBinaryOperatorMethod<uint,    uint>   (this, (a, b) => checked(a % b), (a, b) => unchecked(a % b)),
            new LambdaBinaryOperatorMethod<long,    long>   (this, (a, b) => checked(a % b), (a, b) => unchecked(a % b)),
            new LambdaBinaryOperatorMethod<ulong,   ulong>  (this, (a, b) => checked(a % b), (a, b) => unchecked(a % b)),
            new LambdaBinaryOperatorMethod<float,   float>  (this, (a, b) => checked(a % b), (a, b) => unchecked(a % b)),
            new LambdaBinaryOperatorMethod<double,  double> (this, (a, b) => checked(a % b), (a, b) => unchecked(a % b)),
            new LambdaBinaryOperatorMethod<decimal, decimal>(this, (a, b) => checked(a % b), (a, b) => unchecked(a % b))
          ));
        }
      }
    }
    
    // C# 4.0 spec: §7.8.3 Addition operator
    OperatorMethod[] additionOperators;
    
    public OperatorMethod[] AdditionOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref additionOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref additionOperators, Lift(
            new LambdaBinaryOperatorMethod<int,     int>    (this, (a, b) => checked(a + b), (a, b) => unchecked(a + b)),
            new LambdaBinaryOperatorMethod<uint,    uint>   (this, (a, b) => checked(a + b), (a, b) => unchecked(a + b)),
            new LambdaBinaryOperatorMethod<long,    long>   (this, (a, b) => checked(a + b), (a, b) => unchecked(a + b)),
            new LambdaBinaryOperatorMethod<ulong,   ulong>  (this, (a, b) => checked(a + b), (a, b) => unchecked(a + b)),
            new LambdaBinaryOperatorMethod<float,   float>  (this, (a, b) => checked(a + b), (a, b) => unchecked(a + b)),
            new LambdaBinaryOperatorMethod<double,  double> (this, (a, b) => checked(a + b), (a, b) => unchecked(a + b)),
            new LambdaBinaryOperatorMethod<decimal, decimal>(this, (a, b) => checked(a + b), (a, b) => unchecked(a + b)),
            new StringConcatenation(this, TypeCode.String, TypeCode.String),
            new StringConcatenation(this, TypeCode.String, TypeCode.Object),
            new StringConcatenation(this, TypeCode.Object, TypeCode.String)
          ));
        }
      }
    }
    
    // not in this list, but handled manually: enum addition, delegate combination
    sealed class StringConcatenation : BinaryOperatorMethod
    {
      bool canEvaluateAtCompileTime;
      
      public StringConcatenation(CSharpOperators operators, TypeCode p1, TypeCode p2)
        : base(operators.compilation)
      {
        this.canEvaluateAtCompileTime = p1 == TypeCode.String && p2 == TypeCode.String;
        this.ReturnType = operators.compilation.FindType(KnownTypeCode.String);
        this.Parameters.Add(operators.MakeParameter(p1));
        this.Parameters.Add(operators.MakeParameter(p2));
      }
      
      public override bool CanEvaluateAtCompileTime {
        get { return canEvaluateAtCompileTime; }
      }
      
      public override object Invoke(CSharpResolver resolver, object lhs, object rhs)
      {
        return string.Concat(lhs, rhs);
      }
    }
    
    // C# 4.0 spec: §7.8.4 Subtraction operator
    OperatorMethod[] subtractionOperators;
    
    public OperatorMethod[] SubtractionOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref subtractionOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref subtractionOperators, Lift(
            new LambdaBinaryOperatorMethod<int,     int>    (this, (a, b) => checked(a - b), (a, b) => unchecked(a - b)),
            new LambdaBinaryOperatorMethod<uint,    uint>   (this, (a, b) => checked(a - b), (a, b) => unchecked(a - b)),
            new LambdaBinaryOperatorMethod<long,    long>   (this, (a, b) => checked(a - b), (a, b) => unchecked(a - b)),
            new LambdaBinaryOperatorMethod<ulong,   ulong>  (this, (a, b) => checked(a - b), (a, b) => unchecked(a - b)),
            new LambdaBinaryOperatorMethod<float,   float>  (this, (a, b) => checked(a - b), (a, b) => unchecked(a - b)),
            new LambdaBinaryOperatorMethod<double,  double> (this, (a, b) => checked(a - b), (a, b) => unchecked(a - b)),
            new LambdaBinaryOperatorMethod<decimal, decimal>(this, (a, b) => checked(a - b), (a, b) => unchecked(a - b))
          ));
        }
      }
    }
    
    // C# 4.0 spec: §7.8.5 Shift operators
    OperatorMethod[] shiftLeftOperators;
    
    public OperatorMethod[] ShiftLeftOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref shiftLeftOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref shiftLeftOperators, Lift(
            new LambdaBinaryOperatorMethod<int,   int>(this, (a, b) => a << b),
            new LambdaBinaryOperatorMethod<uint,  int>(this, (a, b) => a << b),
            new LambdaBinaryOperatorMethod<long,  int>(this, (a, b) => a << b),
            new LambdaBinaryOperatorMethod<ulong, int>(this, (a, b) => a << b)
          ));
        }
      }
    }
    
    OperatorMethod[] shiftRightOperators;
    
    public OperatorMethod[] ShiftRightOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref shiftRightOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref shiftRightOperators, Lift(
            new LambdaBinaryOperatorMethod<int,   int>(this, (a, b) => a >> b),
            new LambdaBinaryOperatorMethod<uint,  int>(this, (a, b) => a >> b),
            new LambdaBinaryOperatorMethod<long,  int>(this, (a, b) => a >> b),
            new LambdaBinaryOperatorMethod<ulong, int>(this, (a, b) => a >> b)
          ));
        }
      }
    }
    #endregion
    
    #region Equality operators
    sealed class EqualityOperatorMethod : BinaryOperatorMethod
    {
      public readonly TypeCode Type;
      public readonly bool Negate;
      
      public EqualityOperatorMethod(CSharpOperators operators, TypeCode type, bool negate)
        : base(operators.compilation)
      {
        this.Negate = negate;
        this.Type = type;
        this.ReturnType = operators.compilation.FindType(KnownTypeCode.Boolean);
        this.Parameters.Add(operators.MakeParameter(type));
        this.Parameters.Add(operators.MakeParameter(type));
      }
      
      public override bool CanEvaluateAtCompileTime {
        get { return Type != TypeCode.Object; }
      }
      
      public override object Invoke(CSharpResolver resolver, object lhs, object rhs)
      {
        if (lhs == null && rhs == null)
          return !Negate; // ==: true; !=: false
        if (lhs == null || rhs == null)
          return Negate; // ==: false; !=: true
        lhs = resolver.CSharpPrimitiveCast(Type, lhs);
        rhs = resolver.CSharpPrimitiveCast(Type, rhs);
        bool equal;
        if (Type == TypeCode.Single) {
          equal = (float)lhs == (float)rhs;
        } else if (Type == TypeCode.Double) {
          equal = (double)lhs == (double)rhs;
        } else {
          equal = object.Equals(lhs, rhs);
        }
        return equal ^ Negate;
      }
      
      public override OperatorMethod Lift(CSharpOperators operators)
      {
        if (Type == TypeCode.Object || Type == TypeCode.String)
          return null;
        else
          return new LiftedEqualityOperatorMethod(operators, this);
      }
    }
    
    sealed class LiftedEqualityOperatorMethod : BinaryOperatorMethod, OverloadResolution.ILiftedOperator
    {
      readonly EqualityOperatorMethod baseMethod;
      
      public LiftedEqualityOperatorMethod(CSharpOperators operators, EqualityOperatorMethod baseMethod)
        : base(operators.compilation)
      {
        this.baseMethod = baseMethod;
        this.ReturnType = baseMethod.ReturnType;
        IParameter p = operators.MakeNullableParameter(baseMethod.Parameters[0]);
        this.Parameters.Add(p);
        this.Parameters.Add(p);
      }
      
      public override bool CanEvaluateAtCompileTime {
        get { return baseMethod.CanEvaluateAtCompileTime; }
      }
      
      public override object Invoke(CSharpResolver resolver, object lhs, object rhs)
      {
        return baseMethod.Invoke(resolver, lhs, rhs);
      }
      
      public IList<IParameter> NonLiftedParameters {
        get { return baseMethod.Parameters; }
      }
    }
    
    // C# 4.0 spec: §7.10 Relational and type-testing operators
    static readonly TypeCode[] valueEqualityOperatorsFor = {
      TypeCode.Int32, TypeCode.UInt32,
      TypeCode.Int64, TypeCode.UInt64,
      TypeCode.Single, TypeCode.Double,
      TypeCode.Decimal,
      TypeCode.Boolean
    };
    
    OperatorMethod[] valueEqualityOperators;
    
    public OperatorMethod[] ValueEqualityOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref valueEqualityOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref valueEqualityOperators, Lift(
            valueEqualityOperatorsFor.Select(c => new EqualityOperatorMethod(this, c, false)).ToArray()
          ));
        }
      }
    }
    
    OperatorMethod[] valueInequalityOperators;
    
    public OperatorMethod[] ValueInequalityOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref valueInequalityOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref valueInequalityOperators, Lift(
            valueEqualityOperatorsFor.Select(c => new EqualityOperatorMethod(this, c, true)).ToArray()
          ));
        }
      }
    }
    
    OperatorMethod[] referenceEqualityOperators;
    
    public OperatorMethod[] ReferenceEqualityOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref referenceEqualityOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref referenceEqualityOperators, Lift(
            new EqualityOperatorMethod(this, TypeCode.Object, false),
            new EqualityOperatorMethod(this, TypeCode.String, false)
          ));
        }
      }
    }
    
    OperatorMethod[] referenceInequalityOperators;
    
    public OperatorMethod[] ReferenceInequalityOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref referenceInequalityOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref referenceInequalityOperators, Lift(
            new EqualityOperatorMethod(this, TypeCode.Object, true),
            new EqualityOperatorMethod(this, TypeCode.String, true)
          ));
        }
      }
    }
    #endregion
    
    #region Relational Operators
    sealed class RelationalOperatorMethod<T1, T2> : BinaryOperatorMethod
    {
      readonly Func<T1, T2, bool> func;
      
      public RelationalOperatorMethod(CSharpOperators operators, Func<T1, T2, bool> func)
        : base(operators.compilation)
      {
        this.ReturnType = operators.compilation.FindType(KnownTypeCode.Boolean);
        this.Parameters.Add(operators.MakeParameter(Type.GetTypeCode(typeof(T1))));
        this.Parameters.Add(operators.MakeParameter(Type.GetTypeCode(typeof(T2))));
        this.func = func;
      }
      
      public override bool CanEvaluateAtCompileTime {
        get { return true; }
      }
      
      public override object Invoke(CSharpResolver resolver, object lhs, object rhs)
      {
        if (lhs == null || rhs == null)
          return null;
        return func((T1)resolver.CSharpPrimitiveCast(Type.GetTypeCode(typeof(T1)), lhs),
                    (T2)resolver.CSharpPrimitiveCast(Type.GetTypeCode(typeof(T2)), rhs));
      }
      
      public override OperatorMethod Lift(CSharpOperators operators)
      {
        var lifted = new LiftedBinaryOperatorMethod(operators, this);
        lifted.ReturnType = this.ReturnType; // don't lift the return type for relational operators
        return lifted;
      }
    }
    
    OperatorMethod[] lessThanOperators;
    
    public OperatorMethod[] LessThanOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref lessThanOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref lessThanOperators, Lift(
            new RelationalOperatorMethod<int, int>        (this, (a, b) => a < b),
            new RelationalOperatorMethod<uint, uint>      (this, (a, b) => a < b),
            new RelationalOperatorMethod<long, long>      (this, (a, b) => a < b),
            new RelationalOperatorMethod<ulong, ulong>    (this, (a, b) => a < b),
            new RelationalOperatorMethod<float, float>    (this, (a, b) => a < b),
            new RelationalOperatorMethod<double, double>  (this, (a, b) => a < b),
            new RelationalOperatorMethod<decimal, decimal>(this, (a, b) => a < b)
          ));
        }
      }
    }
    
    OperatorMethod[] lessThanOrEqualOperators;
    
    public OperatorMethod[] LessThanOrEqualOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref lessThanOrEqualOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref lessThanOrEqualOperators, Lift(
            new RelationalOperatorMethod<int, int>        (this, (a, b) => a <= b),
            new RelationalOperatorMethod<uint, uint>      (this, (a, b) => a <= b),
            new RelationalOperatorMethod<long, long>      (this, (a, b) => a <= b),
            new RelationalOperatorMethod<ulong, ulong>    (this, (a, b) => a <= b),
            new RelationalOperatorMethod<float, float>    (this, (a, b) => a <= b),
            new RelationalOperatorMethod<double, double>  (this, (a, b) => a <= b),
            new RelationalOperatorMethod<decimal, decimal>(this, (a, b) => a <= b)
          ));
        }
      }
    }
    
    OperatorMethod[] greaterThanOperators;
    
    public OperatorMethod[] GreaterThanOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref greaterThanOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref greaterThanOperators, Lift(
            new RelationalOperatorMethod<int, int>        (this, (a, b) => a > b),
            new RelationalOperatorMethod<uint, uint>      (this, (a, b) => a > b),
            new RelationalOperatorMethod<long, long>      (this, (a, b) => a > b),
            new RelationalOperatorMethod<ulong, ulong>    (this, (a, b) => a > b),
            new RelationalOperatorMethod<float, float>    (this, (a, b) => a > b),
            new RelationalOperatorMethod<double, double>  (this, (a, b) => a > b),
            new RelationalOperatorMethod<decimal, decimal>(this, (a, b) => a > b)
          ));
        }
      }
    }
    
    OperatorMethod[] greaterThanOrEqualOperators;
    
    public OperatorMethod[] GreaterThanOrEqualOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref greaterThanOrEqualOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref greaterThanOrEqualOperators, Lift(
            new RelationalOperatorMethod<int, int>        (this, (a, b) => a >= b),
            new RelationalOperatorMethod<uint, uint>      (this, (a, b) => a >= b),
            new RelationalOperatorMethod<long, long>      (this, (a, b) => a >= b),
            new RelationalOperatorMethod<ulong, ulong>    (this, (a, b) => a >= b),
            new RelationalOperatorMethod<float, float>    (this, (a, b) => a >= b),
            new RelationalOperatorMethod<double, double>  (this, (a, b) => a >= b),
            new RelationalOperatorMethod<decimal, decimal>(this, (a, b) => a >= b)
          ));
        }
      }
    }
    #endregion
    
    #region Bitwise operators
    OperatorMethod[] logicalAndOperators;
    
    public OperatorMethod[] LogicalAndOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref logicalAndOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref logicalAndOperators, new OperatorMethod[] {
                                    new LambdaBinaryOperatorMethod<bool, bool>(this, (a, b) => a & b)
                                   });
        }
      }
    }
    
    
    OperatorMethod[] bitwiseAndOperators;
    
    public OperatorMethod[] BitwiseAndOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref bitwiseAndOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref bitwiseAndOperators, Lift(
            new LambdaBinaryOperatorMethod<int, int>    (this, (a, b) => a & b),
            new LambdaBinaryOperatorMethod<uint, uint>  (this, (a, b) => a & b),
            new LambdaBinaryOperatorMethod<long, long>  (this, (a, b) => a & b),
            new LambdaBinaryOperatorMethod<ulong, ulong>(this, (a, b) => a & b),
            this.LogicalAndOperators[0]
          ));
        }
      }
    }
    
    
    OperatorMethod[] logicalOrOperators;
    
    public OperatorMethod[] LogicalOrOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref logicalOrOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref logicalOrOperators, new OperatorMethod[] {
                                    new LambdaBinaryOperatorMethod<bool, bool>(this, (a, b) => a | b)
                                   });
        }
      }
    }
    
    OperatorMethod[] bitwiseOrOperators;
    
    public OperatorMethod[] BitwiseOrOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref bitwiseOrOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref bitwiseOrOperators, Lift(
            new LambdaBinaryOperatorMethod<int, int>    (this, (a, b) => a | b),
            new LambdaBinaryOperatorMethod<uint, uint>  (this, (a, b) => a | b),
            new LambdaBinaryOperatorMethod<long, long>  (this, (a, b) => a | b),
            new LambdaBinaryOperatorMethod<ulong, ulong>(this, (a, b) => a | b),
            this.LogicalOrOperators[0]
          ));
        }
      }
    }
    
    // Note: the logic for the lifted bool? bitwise operators is wrong;
    // we produce "true | null" = "null" when it should be true. However, this is irrelevant
    // because bool? cannot be a compile-time type.
    
    OperatorMethod[] bitwiseXorOperators;

    public OperatorMethod[] BitwiseXorOperators {
      get {
        OperatorMethod[] ops = LazyInit.VolatileRead(ref bitwiseXorOperators);
        if (ops != null) {
          return ops;
        } else {
          return LazyInit.GetOrSet(ref bitwiseXorOperators, Lift(
            new LambdaBinaryOperatorMethod<int, int>    (this, (a, b) => a ^ b),
            new LambdaBinaryOperatorMethod<uint, uint>  (this, (a, b) => a ^ b),
            new LambdaBinaryOperatorMethod<long, long>  (this, (a, b) => a ^ b),
            new LambdaBinaryOperatorMethod<ulong, ulong>(this, (a, b) => a ^ b),
            new LambdaBinaryOperatorMethod<bool, bool>  (this, (a, b) => a ^ b)
          ));
        }
      }
    }
    #endregion
  }
}